FitSugar

Your Contact Lenses Could Make You Blind

FitSugar — Thu, 23 Oct 2008 03:00:00 -0700

Many of you rely on your contact lenses in order to help you see, but your lenses could end up taking away your vision. What an ugly irony. The problem starts with a simple single cell microorganism - acanthamoeba.

Acanthamoeba is one of the most common types of protozoan that live in soil and fresh water. They can be found in city tap water, so if you rinse your lens case in water from the sink, this amoeba can be transferred to your contact lenses and then to your eye. These protozoan can live and multiply in both your contact case and your eyes, and can go back and forth between the two because commercial contact lens solution can't kill them. Once they're in your eyes, they can cause a painful infection known as amoebic keratitis, which can lead to blindness. The prevalence of this infection has increased because so many people wear contact lenses now.

The lenses that you wear for a year or two were found to contain the most pathogenic (disease-causing) strains of acanthamoeba. The ones that you keep for a month or two weeks contained fewer, and the daily lenses contained no acanthamoeba. Talk to your eye doctor about the kinds of contact lenses you wear to see which would be the healthiest for your eyes. Scientists are on the move trying to develop a contact lens solution that can kill this nasty amoeba, but for now, it's recommended that you don't rinse your lens case in tap water.

Source

Color blindness

admin — Wed, 03 Sep 2008 17:53:42 -0700

HEALTH GUIDE REFERENCE FROM A.D.A.M

Definition

Color blindness is the inability to see certain colors in the usual way.

Alternative Names

Color deficiency; Blindness - color

Causes, incidence, and risk factors

Color blindness occurs when there is a problem with the color-sensing materials (pigments) in certain nerve cells of the eye. These cells are called cones. They are found in the retina, the light-sensitive layer of tissue at the back of the inner eye.

If you are missing just one pigment, you might have trouble telling the difference between red and green. This is the most common type of color blindness. Other times, people have trouble seeing blue-yellow colors. People with blue-yellow color blindness almost always have problems identify reds and greens, too.

The most severe form of color blindness is achromatopsia. A person with this rare condition cannot see any color. Achromatopsia is often associated with lazy eye, nystagmus (small, jerky eye movements), severe light sensitivity, and extremely poor vision.

Most color blindness is due to a genetic problem. (See: X-linked recessive) About 1 in 10 men have some form of color blindness. Very few women are color blind.

The drug hydroxychloroquine (Plaquenil) can also cause color blindness. It is used to treat rheumatoid arthritis, among other conditions.

Symptoms

Symptoms vary from person to person, but may include:

Trouble seeing colors and the brightness of colors in the usual way
Inability to tell the difference between shades of the same or similar colors

Often, the symptoms may be so mild that some persons do not know they are color blind. A parent may notice signs of color blindness when a child is learning his or her colors.

Rapid, side-to-side eye movements and other symptoms may occur in severe cases.

Signs and tests

Your doctor or eye specialist can check your color vision in several ways. Testing for color blindness is commonly done during an eye exam.

Treatment

There is no known treatment.

Expectations (prognosis)

Color blindness is a life-long condition. Most persons are able to adjust without difficulty or disability.

Complications

Those who are colorblind may not be able to get a job that requires color vision. For example, a pilot needs to be able to see colors.

Calling your health care provider

Make an appointment with your health care provider or ophthalmologist if you think you (or your child) have color blindness.

References

Yanoff M, Duker JS, Augsburger JJ, et al. Ophthalmology. 2nd ed. St. Louis, Mo: Mosby; 2004:34.

Goldman L, Ausiello D. Cecil Textbook of Medicine, 22nd ed. Philadelphia, Pa: WB Saunders; 2004:2410.

Review Date: 2/22/2007

Reviewed By: Manju Subramanian, MD, Assistant Professor in Ophthalmology, Vitreoretinal Disease and Surgery, Boston University Eye Associates, Boston, MA. Review provided by VeriMed Healthcare Network.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

A.D.A.M. Copyright

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-2009 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

adam.com

Source Doc: 1_001002

Blindness

admin — Thu, 04 Sep 2008 19:04:12 -0700

Overview

Definition
Alternative Names
Common Causes
Home Care
Call your health care provider if
What to expect at your health care provider's office

Illustrations

Neurofibromatosis I, enlarged optic foramen

HEALTH GUIDE REFERENCE FROM A.D.A.M

Definition

Blindness is a lack of vision. It may also refer to a loss of vision that cannot be corrected with glasses or contact lenses.

Partial blindness means you have very limited vision.
Complete blindness means you cannot see anything and do not see light.

People with vision worse than 20/200 are considered legally blind in most states in the United States.

Alternative Names

Loss of vision

Common Causes

Blindness has many causes. In the United States, the leading causes are diabetes, glaucoma, macular degeneration, and accidents (such as chemical burns or sports injuries).

Worldwide, the leading causes of blindness are cataracts, onchocerciasis (river blindness), trachoma, leprosy, and vitamin A deficiency.

Other causes include:

Blocked blood vessels
Complications of premature birth (retrolental fibroplasia)
Complications of eye surgery
Lazy eye
Optic neuritis
Stroke
Tay-Sachs disease
Retinitis pigmentosa
Retinoblastoma
Lead poisoning
Optic glioma

Home Care

It is important for a blind person to be able to dress, eat, function independently, and stay safe. Many services are available that provide the training and support that allow blind people to function independently.

Call your health care provider if

Sudden vision loss is always an emergency, even you have not completely lost all vision. You should never ignore loss of vision, thinking it will get better.

Contact an ophthalmologist or go to the emergency room immediately. Most serious forms of vision loss are painless, and the absence of pain in no way diminishes the urgent need to get medical care. Many forms of vision loss only give you a short amount of time to be successfully treated.

What to expect at your health care provider's office

A complete and thorough eye examination will be performed. The treatment plan will depend on the cause.

A.D.A.M. Copyright

adam.com

Source Doc: 1_003040

Vision - night blindness

admin — Thu, 04 Sep 2008 19:04:11 -0700

Overview

Definition
Alternative Names
Considerations
Common Causes
Home Care
Call your health care provider if
What to expect at your health care provider's office

Illustrations

External and internal eye anatomy

HEALTH GUIDE REFERENCE FROM A.D.A.M

Definition

Night blindness is poor vision at night or in dim light.

Alternative Names

Nyctanopia; Nyctalopia; Night blindness

Considerations

Night blindness may cause problems with driving in the evening or at night. People with night blindness often have trouble seeing the stars on a clear night.

Common Causes

Cataracts
Retinitis pigmentosa
Vitamin A deficiency
Certain drugs
Birth defects

In some cases, the eyes may simply have trouble adapting to darkness. The problem may not be due to another medical condition. However, it is often linked to myopia (nearsightedness).

Home Care

Take safety measures to prevent accidents in the areas of low light. Avoid driving a car at night.

Vitamin A supplements may be helpful.

Call your health care provider if

It is important to have a complete eye exam to determine the cause, which may be treatable. Call your eye doctor if symptoms of night blindness persist or significantly affect your life.

What to expect at your health care provider's office

Your health care provider will examine you and your eyes. The goal of the medical exam is to determine if the problem can be corrected (for example, with new glasses or cataract removal), or if the problem is due to something more serious.

The doctor may ask you questions, including:

When did the night blindness begin?
Did it occur suddenly or gradually?
Does it happen all the time or just sometimes?
How severe is the night blindness?
Are you nearsighted?
Do you have other vision changes?
What other symptoms do you have?
Do you have unusual stress, anxiety, or a fear of the dark?
Does use of corrective lenses improve night vision?
What medications do you use?
How is your diet?
Have you recently injured your eyes or head?
Do you have a family history of diabetes?

A slit lamp examination may be done.

A.D.A.M. Copyright

adam.com

Source Doc: 1_003039

Blind loop syndrome

admin — Wed, 03 Sep 2008 17:54:48 -0700

Overview

Definition
Alternative Names
Causes, incidence, and risk factors
Symptoms
Signs and tests
Treatment
Expectations (prognosis)
Complications
Calling your health care provider
References

Illustrations

Digestive system

Stomach and small intestine

HEALTH GUIDE REFERENCE FROM A.D.A.M

Definition

Blind loop syndrome occurs when part of the intestine becomes blocked, so that digested food slows or stops moving through the intestines. This causes bacteria to overgrow in the intestines and causes problems in absorbing nutrients.

Alternative Names

Stasis syndrome; Stagnant loop syndrome

Causes, incidence, and risk factors

The name of this condition refers to the "blind loop" formed by the blocked intestine. This blind loop does not allow the normal flow of digested food through the intestinal tract.

When a section of the intestine is blocked by blind loop syndrome, bile salts needed to digest fats become ineffective, resulting in fatty stools and poor absorption of fat and fat-soluble vitamins. Vitamin B12 deficiency may occur because the extra bacteria that develop in this situation use up all of the vitamin.

Blind loop syndrome is a complication that occurs after many operations, including subtotal gastrectomy (surgical removal of part of the stomach), operations for extreme obesity, or as a complication of inflammatory bowel disease or scleroderma.

Symptoms

Signs and tests

During a physical examination, the doctor may notice a mass in, or swelling of, the abdomen. Possible tests include:

Abdominal CT scan
Abdominal x-ray
Contrast enema study

Treatment

The initial treatment generally involves antibiotics for the bacterial overgrowth, along with vitamin B12 supplementation. If antibiotics don't work, surgery to help the flow of food through the intestine may be considered.

Expectations (prognosis)

Many patients get better with antibiotics. If surgical repair is required, the outcome is typically very good.

Complications

Complete intestinal obstruction
Intestinal infarction (death of intestine)
Perforation (hole) of intestine

Calling your health care provider

Call your health care provider if you have symptoms of blind loop syndrome.

References

Townsend CM, Beauchamp RD, Evers BM, Mattox KL. Sabiston Textbook of Surgery, 18th ed. Philadelphia, Pa: Saunders Elsevier; 2008.

Review Date: 3/8/2008

Reviewed By: Christian Stone, MD, Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M. Copyright

adam.com

Source Doc: 1_001146

Blindness - resources

admin — Thu, 04 Sep 2008 18:52:46 -0700

Overview

Alternative Names
Information

Illustrations

Support group counselors

HEALTH GUIDE REFERENCE FROM A.D.A.M

Alternative Names

Resources - blindness

Information

The following organizations are good resources for information on blindness:

American Foundation for the Blind - www.afb.org
American Council of the Blind - www.acb.org
National Library Service for the Blind and Physically Handicapped - www.loc.gov/nls

Review Date: 10/13/2006

Reviewed By: A.D.A.M. Editorial Team: Greg Juhn, M.T.P.W., David R. Eltz, Kelli A. Stacy.

A.D.A.M. Copyright

adam.com

Source Doc: 1_002186

Color blindness tests

admin — Thu, 04 Sep 2008 19:42:19 -0700

Back

HEALTH GUIDE REFERENCE FROM A.D.A.M

Color blindness is the inability to distinguish the differences between certain colors. The most common type is red-green color blindness, where red and green are seen as the same color. Usually Isihara (pseudoisochromatic) plates are used to test color vision. They are made of dot patterns composed of primary colors. These dot patterns represent a symbol that is superimposed on a background of randomly mixed colors. The test can determine certain abnormalities in a person's color vision.

A.D.A.M. Copyright

adam.com

Source Doc: 2_9962

Wed, 31 Dec 1969 16:00:00 -0800

Glaucoma

FitSugar — Wed, 08 Oct 2008 17:35:34 -0700

In This Report

Highlights
Introduction
Causes
Symptoms
Outlook
Risk Factors
Diagnosis
Treatment
Medications
Surgery
Lifestyle Changes
Resources
References

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

Drug Approval

Bimatoprost (Lumigan) has been approved as a first-line treatment for open-angle glaucoma.

Glaucoma Cases Increasing Worldwide

About 60 million people worldwide will have glaucoma by 2010, and the number will increase to nearly 80 million by 2010, according to a recent study in the British Journal of Ophthalmology.

Weightlifting May Increase Glaucoma Risk

Weightlifting can cause a temporary increase in intraocular eye pressure (IOP), and holding your breath while lifting weights further increases IOP, suggests a 2006 study in the Archives of Ophthalmology. Doctors should ask patients with normal-tension glaucoma if they engage in weightlifting exercise.

IOP and Posture

IOP increases in some people when they are lying prone during sleep, yet glaucoma exams measure IOP in patients while they are sitting upright and awake, notes a 2006 study in the Archives of Ophthalmology. The researchers caution that posture may affect the interpretation of IOP readings.

Pregnancy and Glaucoma

The course of glaucoma is unpredictable during pregnancy -- IOP may remain stable in some women and increase in others, indicates a 2006 study. Although glaucoma eye drops can increase the risk of some pregnancy problems, especially during the first trimester, some pregnant women may need to continue to take glaucoma medication. Be sure your ophthalmologist carefully evaluates your individual case and explains the risks and benefits of taking medication during pregnancy.

Diabetes and Glaucoma

Type 2 diabetes increases the risk for open-angle glaucoma (the most common type of glaucoma). People with type 2 diabetes need to get regular glaucoma screenings.

Glaucoma Surgery

Tube shunts may work better than trabulectomy surgery for some patients with glaucoma, suggests a 2007 study.
Phacoviscocanalostomy, a surgery procedure that combines phacoemulsification (used for cataract surgery) and viscocanalostomy (used for glaucoma surgery), is safe and effective for patients who have both glaucoma and cataracts, indicates a 2006 study.

Introduction

Glaucoma is defined as a disease of the optic nerve, in which the nerve cells in the front of the optic nerve (the ganglion cells) die. The process is irreversible. Previously, it was believed that glaucoma was almost always due to increased intraocular pressure. However, glaucoma has been observed in many patients with normal and even low eye pressure, so the definition now rests on the damage to the optic nerve.

The Aqueous Humor. In understanding of glaucoma, it is important to first consider aqueous humor, the clear, watery fluid that circulates continuously through the front (anterior) chamber of the healthy eye and is a primary focus of glaucoma research. (This fluid is not related to tears, nor is it the dense jelly-like substance called vitreous humor that is contained in the rear chamber.) It serves two important functions in the eye:

It nourishes the area around the colored iris and behind the cornea.
It exerts pressure to help maintain the eye’s shape.

Draining the Fluid and Intraocular Pressure. The aqueous fluid is continuously produced within the front of the eye, causing pressure known as intraocular pressure (IOP). To offset the in-flowing fluid and to maintain normal IOP, the fluid drains out between the iris and cornea (an area known as the drainage angle). It does so through two channels within this angle:

The trabecular meshwork, a sponge-like, porous network, and its connecting passageways are referred to as the "conventional" outflow pathway. Most of the eye fluid outflow occurs in this region and flows from the trabecular meshwork to a group of vessels encircling the anterior chamber, called Schlemm's canal. From here, the fluid enters collection chambers and then flows out into the general blood circulatory system of the body.
The uveoscleral pathway is located behind the trabecular meshwork and is called the "unconventional" pathway. Up to 30% of the fluid flows out through this channel.

Intraocular Eye Pressure. Previously, it was believed that glaucoma was almost always due to an abnormal rise in intraocular pressure.

Glaucoma is a condition of increased fluid pressure inside the eye. The increased pressure causes compression of the retina and the optic nerve which can eventually lead to nerve damage. Glaucoma can cause partial vision loss, with blindness as a possible eventual outcome.

Increased IOP is, indeed, present in most cases of glaucoma, but some patients have normal IOP, which is usually maintained at measurements of 10 - 20 mm Hg. Measurements above this, however, do not necessarily predict glaucoma. For example, only about 10% of people with IOP levels between 21 - 30 mm Hg will actually develop glaucoma. This still puts such individuals at considerable risk for glaucoma, however.

Most people with glaucoma have the form called primary-open-angle glaucoma (also called chronic open-angle glaucoma). Open-angle glaucoma is essentially a plumbing problem.

The disease process may occur as follows:

The drainage angle remains open, but tiny drainage channels in the trabecular meshwork pathway become clogged. This pathway is responsible for most aqueous humor fluid outflow. An imbalance then occurs as fluid continues to be produced but does not drain out efficiently. Experts have still not definitely determined the precise area in the pathway where the blockage is most likely to occur. (In rare instances the pressure is high because the eye produces too much aqueous humor.)
The fluid in the eye’s anterior chamber builds up and increases pressure within the eye. This is called intraocular pressure (IOP).
The intraocular pressure exerts force on the optic nerve at the back of the eye.
Over time, the persistent pressure or other factors irreversibly damages the delicate long fibers of the optic nerve, called axons, which convey images to the brain.
As these axons die, the small cup-like head of the optic nerve may eventually collapse into an enlarged irregular shape.

Optic nerve damage is the basic glaucoma condition. If it is untreated, eventually the nerve deteriorates until a person loses sight, first in the peripheral vision (the vision in the "corner of the eyes"). If it becomes severe, the person loses central vision (in the middle of the eyes), and may eventually become blind. (Blindness is fortunately nearly always preventable with early treatment.)

Primary open-angle glaucoma tends to start in one eye but eventually involves both. In about half of patients the damage in the eye is diffuse, that is the nerve damage is generalized. In the other half the disease is localized, causing wedge-shaped abnormalities in the nerve fiber layers of the retina.

Intraocular eye pressure is normal (between 12 - 22 mmHg) in about 25 - 30% of U.S. glaucoma cases, a condition known as normal-tension glaucoma. (In Japan, the rates may be as high as 70%.) Other factors are present that cause optic nerve damage but do not affect IOP.

Closed-angle glaucoma (also called angle-closure glaucoma) is responsible for 15% of all cases. It is less common than open-angle glaucoma in the U.S., but it constitutes about half of the world's glaucoma cases because of its higher prevalence among Asians. The iris is pushed against the lens, sometimes sticking to it, closing off the drainage angle. This can occur very suddenly, resulting in an immediate rise in pressure. It often occurs in genetically susceptible people when the pupil shrinks suddenly. Closed-angle glaucoma can also be chronic and gradual, a less common condition.

Congenital glaucoma, in which the eye's drainage canals fail to develop correctly, is present from birth. It is very rare, occurring in about 1 in 10,000 newborns. This may be an inherited condition and often can be corrected with microsurgery.

The Light-Processing Parts. To understand sight, one begins with light and its passage through the eye's sensitive camera-like structures:

Light first passes through the cornea, a clear tissue at the front of the eye.
Behind the cornea, the iris (the colored tissues of the eye) opens and closes like a camera shutter to regulate the passage of light.
The lens, located behind the iris, focuses the light, which then hits the retina.
The retina is an electric fragile membrane of nerve cells called photoreceptors that receive light and translate it into signals.
A layer of cells, called the retinal ganglia, receive signals from the retina. These nerve cells are the front ends of the optic nerve cable, which, in turn, receive the signals.
The optic nerve is actually a cable of about 1.2 million nerve fibers called axons. It carries the signals to the brain, which interprets them as images.
They exit the eye through the optic disc, located in the back of the eye.

The Supportive Chambers. To help support and protect these sensitive structures, the eye contains two fluid-filled chambers:

The posterior (rear) chamber is the large area behind the iris.
Fluid passes from the posterior into the anterior (forward) chamber located in the bulging area between the iris and the front of the eye.

Causes

No single factor has been identified as a cause of primary open-angle glaucoma. A number of conditions, alone or in combination, are needed to trigger the processes leading to pressure in the first place and then to the nerve damage that destroys sight. The damage done to the optic nerve in glaucoma is triggered in most cases by the excessive pressure on the optic nerve that, over time, causes damage. Because optic nerve damage occurs in patients with normal as well as high intraocular pressure, however, researchers are investigating several other abnormal events that occur and can damage the optic nerve.

A number of genes have now been identified as possible factors in many cases of glaucoma. A gene called MYOC is of particular interest. Defects in this gene occur in between 3 - 6% of patients with adult-onset and juvenile open-angle glaucoma. They appear to overproduce a sticky protein called myocilin, which clogs the trabecular meshwork. The genes WDR36 and OPTN may cause primary open-angle glaucoma. Researchers hope that identification of genes will help improve screening of high-risk patients.

Specific syndromes have been identified with glaucoma. Many have an inherited component, although in most cases other factors must be present to activate the disease process.

Pseudoexfoliation Syndrome. Pseudoexfoliation (PEX) syndrome (also known as exfoliation syndrome) is the most common identifiable condition associated with glaucoma. In one study, 9% of patients with open-angle glaucoma had the syndrome. PEX occurs when dandruff-like matter flakes off the outer layer of the lens and collects in the drainage angle. The substance is composed of proteins produced by the lens, iris, and other parts of the eye. People can have this condition and not develop glaucoma, but they are at high risk. In one Australian study, 14% of the people with this condition had glaucoma compared to 2% of those without exfoliation. PEX has a strong genetic component but other factors (possibly sunlight, an autoimmune response, or slow virus) may be needed to trigger the disease.

Pigment Glaucoma. Pigment glaucoma starts with a condition called pigment dispersion syndrome, an inherited condition in which granules of pigment (the substance that colors the iris) flakes off into the intraocular fluid. In about 30% of cases, these fragments clog the trabecular meshwork and pressure builds up, causing glaucoma. In one study, 2% of patients had this form of glaucoma.

Irido Corneal Endothelia Syndrome. In irido corneal endothelial syndrome (ICE), cells on the back surface of the cornea spread to the drainage angle, sometimes forming scars that connect the iris to the cornea.

Neovascular Glaucoma. Neovascular glaucoma is always associated with other disorders, usually diabetes, that result in abnormal formation of new blood vessels on the iris and in the drainage system.

Aniridia. Aniridia is a rare inherited disorder (in which the iris is abnormal and increases the risk for glaucoma) that is difficult to treat. (A surgical approach called goniosurgery may help prevent glaucoma in young people with aniridia.)

Congenital Glaucoma. When an infant is born with glaucoma (congenital glaucoma), it is usually caused by an inherited abnormality in the drainage canal. Researchers have identified the gene responsible for 85% of these cases.

A natural process called apoptosis (cellular self-destruction) may contribute to damage in the retinal ganglion nerve cells, the nerve cells that are the front line of the optic nerve. Cell death can occur with or without elevated eye pressure. It is not clear what triggers apoptosis and cell death in such cases, but there are a number of suspects.

Excess Glutamate. Researchers have observed abnormally high levels of glutamate in people and animals with glaucoma. Glutamate is an amino acid that excites nerve cells. In the eye this occurs during vision. Some experts theorize that in glaucoma, either reduced blood flow or increased pressure on nerve cells triggers the release of excess glutamate. In large amounts, glutamate causes the nerve cells to fire intensively, which eventually destroys them.

Reduced Blood Flow. Researchers have observed reduced blood flow to the optic nerve in patients with glaucoma associated with both high and normal IOP. Less blood flow suggests oxygen loss, which may play a role in the destructive process. Some studies suggest that the greatest risk factor for nerve damage in patients is when blood pressure to the eye drops during the night. Ocular pressure at this time is highest, so the risk for nerve damage becomes intensified. Of interest in this regard are reports finding a significant reduction in eye blood pressure at night in patients with normal-tension glaucoma.

Excess Nitric Oxide. Elevated levels of nitric oxide, another nerve-stimulating compound, also plays a role in the nerve-damaging process. Nitric oxide is critical for nerve function and flexible blood vessels, but excess amounts may be toxic to nerves.

Glaucoma and Alzheimer's Disease. Some research has pointed out similarities in the process leading to cell death in glaucoma and Alzheimer's disease. Specifically, in both diseases activation of certain enzymes called caspases occurs and leads to accumulation of fragments of beta amyloid, an insoluble protein that forms sticky patches.

Autoimmunity. Some experts are studying the possibility that normal tension glaucoma may be an autoimmune disease; that is, factors in the immune system, including antibodies, attack cells in the person's own body as if they were foreign substances. In the case of glaucoma, such antibodies would damage parts of the optic nerve.

H. pylori Infection. Some research indicates that glaucoma is associated with Helicobacter (H.) pylori, the bacterium implicated as a major cause of peptic ulcers. Studies have reported over 87% of patients with glaucoma are infected with this bacterium.

People with acute closed-angle glaucoma often have a structural defect that causes a narrow angle between the iris and cornea where the aqueous humor circulates. Conditions that suddenly dilate the pupils may cause this shallow angle to close and precipitate attacks of acute glaucoma in susceptible people. Such conditions may include:

Certain drugs such as antihistamines, tricyclic antidepressants, some asthma medications (nebulized ipratropium), some anti-seizure drugs (topiramate)
Darkness
Emotional stress

When intraocular pressure leading to glaucoma is caused by other diseases or conditions, it is known as secondary glaucoma. Secondary glaucoma may be chronic or acute, mild or severe.

Medical Conditions. A number of diseases can contribute to the development of intraocular pressure leading to glaucoma:

Diseases that affect blood flow to the optic nerve (diabetes, high blood pressure, migraine; people with type 2 diabetes should be regularly screened for glaucoma.)
Hypothyroidism
Sleep apnea
Physical injury in the eye
Extreme nearsightedness (myopia)
Previous eye surgery
Other disorders, including leukemia, sickle cell anemia, and some forms of arthritis

Corticosteroids. Corticosteroids, commonly called steroids, have multiple effects on the trabecular meshwork and may even cause genetic changes. In fact, studying the effects of steroids on the eye is helping researchers understand the glaucoma disease process. Steroids pose a higher or lower risk depending on the form:

Taking topical steroid treatments in the eye poses the highest risk. It must be monitored carefully since, in some cases, damage may be permanent.
Taking oral corticosteroids, particularly in high doses or for long periods, increases the chance of glaucoma. In such cases, the eye disorder typically develops almost immediately and reverses within 2 weeks after the drug has been withdrawn.
Inhaled steroids were not thought to cause glaucoma, but there is some risk in people with a family history of glaucoma and other risk factors.

Symptoms

Chronic glaucoma is insidious. If the pressure increases slowly, it will not produce any symptoms until it has done irreversible damage. In such cases, people may notice visual problems at first only when light is dim. Patients are often sensitive to glare. Eventually they may lose contrast sensitivity; that is, they might have trouble differentiating between varying shades and brightness.

In acute closed-angle glaucoma, the pressure inside the eye increases quickly, and the symptoms are dramatic. Intense pain in the eyebrow area and blurred vision develop usually in one eye, and the patient often feels like the eye will burst (although it won't). The eye usually reddens. A person may see rainbow-like halos around lights. Sometimes nausea and vomiting occur. These symptoms may occur on and off and not appear as a full attack. In either case, they indicate a medical emergency. In chronic closed-angle glaucoma, the process is gradual and painless.

Although congenital glaucoma is usually present at birth, symptoms generally don’t develop in the infant for a few months. If parents notice that an infant’s eyes are enlarging, becoming cloudy, often watering, or tending to close in the presence of light, they should have an ophthalmologist examine the child’s eyes. Port-wine stains on an infant’s face could indicate the Sturge-Weber syndrome, a disorder that occasionally causes glaucoma.

Outlook

Worldwide, glaucoma ranks as one of the leading causes of blindness. Even if people with glaucoma do not become blind, vision can be impaired. In developed countries, most people get treatment in time to preserve their vision. Even so, glaucoma causes between 3 - 6% of blindness cases in Caucasians, and even more cases in African Americans.

In a 20-year study of Caucasian patients with glaucoma, blindness in at least one eye occurred in 27% of patients and blindness in both eyes occurred in 9% of patients. The blindness rates in African Americans are most likely higher. In fact, glaucoma is the leading cause of blindness in African Americans. Despite this higher prevalence, this ethnic group receives surgical treatment at half the rate of Caucasians.

The Process Leading to Vision Loss. Chronic glaucoma is often called “the silent thief of sight," because the afflicted person has no warning sign, no hint that anything is wrong. Untreated, the destruction develops slowly over time:

Over years or decades, the increased pressure compresses nerves at the back of the eyes.
Glaucoma gradually destroys first the outer fibers of the optic nerve, which reduces peripheral vision (the top, sides, and bottom areas of vision), but not central vision.
By the time a person notices that peripheral vision has been lost, permanent damage has already occurred.
If the eye pressure remains high, the destruction can progress until tunnel vision develops, and the person is only able to see objects that are straight ahead.
The last nerve fibers destroyed are those responsible for central vision; if this occurs, the glaucoma victim becomes totally blind.

Although there is no cure for open-angle glaucoma, a number of treatments are available that lower intraocular pressure and slow progression of vision loss.

Risk Factors for Vision Loss. Estimates of progression rates in vision deterioration range from 9 - 30% over a 2 - 7 year period.

According to a study on patients with elevated IOP, for every 1-mm Hg increase in IOP, there is a 10% higher risk of disease progression. A very elevated IOP (above 30 mm Hg) is certainly hazardous. An elevated IOP that is below 30 mm Hg, however, is not necessarily the most important factor in determining the risk for disease progression. Some evidence suggests that frequent and large daily fluctuations in intraocular pressure, not simply high IOP, are associated with the greatest risk for loss of vision. Having normal-tension glaucoma with optic nerve damage also carries a high risk for progression, even if eye pressure is reduced.

In any case, factors other than IOP play a role in increasing the chances for progression and vision loss in patients with slightly elevated IOP and normal tension glaucoma:

Both eyes affected
Pseudoexfoliation (PEX) syndrome. PEX occurs when proteins produced in the eye flake off the outer layer of the lens and collects in the drainage angle.
Bleeding in a specific region called the peripapillary nerve fiber layer
Thin corneas. (People who have thick corneas and elevated IOP may only need to be monitored if they have no other risk factor for vision loss.)
Larger cup-to-optic disc ratio. (The cup of the optic disc is the center portion, which enlarges as nerve damage progresses.)

Non-eye related factors associated with disease progression include being elderly, African American, female, or having a history of migraines.

Acute closed-angle glaucoma is a medical emergency; if the high pressure is not reduced within hours, it may permanently damage vision. Anyone who experiences its symptoms should immediately contact an ophthalmologist or go to a hospital emergency room.

Risk Factors

About 2 million Americans have open-angle glaucoma, but an exact count is unclear. Experts estimate that by 2010, over 60 million people worldwide will have glaucoma, with 74% of these cases due to open-angle glaucoma. Half of people with glaucoma are unaware of this problem because the condition causes no symptoms.

Elevated intraocular pressure in the eye occurs in 5 - 10 million Americans, but only about 10% of such people develop glaucoma because of this pressure. And, in 15% of actual glaucoma cases, IOP is normal. Major studies are helping to clarify the people who are at highest risk for glaucoma and optic nerve damage, including those with normal tension glaucoma.

Elderly. The prevalence of chronic glaucoma increases with age. In a major study, 0.6% of people age 60 - 64 had primary open-angle glaucoma. Among people who were 10 years older, the prevalence had more than doubled to 1.3%, and among those who were age 80 - 84, it had more than doubled again to 3%.

People of African Descent. Across all age groups, according to a 2000 report, the prevalence of glaucoma in African Americans is about 3.5% compared to about 1% in Caucasians. In addition, U.S. studies suggest that glaucoma develops earlier in African American population groups (starting at age 45 instead of age 60 in Caucasians). And, their risk for blindness once they have glaucoma is 14 - 17 times that of Caucasians with glaucoma. African American men are at higher risk than women. African American children who are extremely near-sighted and have relatives with glaucoma should begin regular eye examinations for glaucoma as early as possible.

In a major glaucoma study in Barbados, where most people are of African descent, over 10% of those age 50 and older had open angle glaucoma, and over 15% were afflicted after age 70. About half of the cases had normal or lower eye pressure. An interesting 2001 study suggested that African Americans tend to have significantly thinner central corneas than Caucasians. This could lead to misleadingly lower pressure scores in African American patients who actually may have high IOPs.

Family History. Glaucoma tends to run in families. Brothers and sisters of patients with open angle glaucoma are 5 times more likely to develop glaucoma by the time they are 70 years old than people whose siblings do not have the disease. Previous studies have also found that people with family histories of glaucoma are more likely to already have some vision loss when they are first diagnosed with glaucoma.

Effects of Blood Pressure. The association between a person's blood pressure and intraocular pressure in the eye is not entirely clear. A number of studies have found a higher risk for glaucoma in people with high blood pressure. A 2002 study suggested, however, that people with blood pressure that is low relative to their intraocular pressure may be at higher risk for glaucoma. The same study found no higher risk for glaucoma in people with hypertension, and in fact, high blood pressure was associated with a lower risk.

Having Certain Medical Disorders. Individuals with certain medical or physical conditions, including diabetes, migraine, nearsightedness, and sleep apnea, appear to have a higher risk. Conditions that require the use of any oral or inhaled steroid, particularly high doses for prolonged periods of time, can cause glaucoma. Previous eye surgery also puts people at risk.

Weightlifting. According to a 2006 study, holding your breath while weightlifting can increase the risk for developing normal-tension glaucoma. Weightlifting causes temporary increases in eye pressure; holding your breath during this exercise leads to even greater intraocular pressure.

Risk Factors for Closed-Angle Glaucoma. Chronic closed-angle glaucoma tends to be more common in people of Asian and African descent. Those who have this condition are often extremely farsighted. Acute closed-angle glaucoma occurs much more frequently in women than in men.

Risk Factors for Normal Tension Glaucoma. Risk factors for normal tension glaucoma include Japanese ancestry and a family history of the disease. It is more common in women than in men. A family history of cardiovascular disease also increases the risk.

Risk Factors for Pigmentary Glaucoma. Pigmentary glaucoma occurs three times more often in men then in women and at a younger age.

Risk Factors for Irido Corneal Endothelial Syndrome. This condition occurs more often in light-skinned women.

Diagnosis

A diagnosis of glaucoma no longer simply relies on the presence of pressure within the eye. It requires that there be optic nerve damage or a strong suggestion of damage, which can be clearly seen during a dilated eye examination of the optic nerve. In general, the hallmark sign of this condition is a loss of peripheral vision. With peripheral vision loss, a person can see in front of him- or herself but has lost the vision to the side.

The optic nerve carries the information of vision from the eye to the brain.

Because chronic glaucoma has no warning symptoms, half of its victims are unaware that they have the condition. Early diagnosis, however, is the key to successful treatment of glaucoma. One study reported that the more years since the last visit to an eye professional, the greater the risk for having visual loss.

Everyone over age 65 and African Americans over 40 years old should have periodic eye exams, including tests for glaucoma, every other year.
African Americans between ages 20 - 39 should have eye examinations every 3 - 5 years.
Other people at higher risk (people with diabetes, history of eye injuries, a family history of glaucoma, or those taking corticosteroid medications) should have eye examinations every year after age 35.
People with known glaucoma should have frequent examinations to check peripheral vision and to be sure treatment is maintaining a safe eye pressure. After such examinations, the ophthalmologist will assess current treatment and make necessary adjustments.

Doctors determine the intraocular pressure (IOP) of the aqueous humor inside the eye using tonometry, which measures the force necessary to make an indentation in the eye. There are several methods:

In the Schiotz method, the doctor first anesthetizes the eye with drops, then presses very lightly against it with tonometer, a tiny smooth instrument that is used to measure the pressure.
In the applanation method, the doctor touches a strip of orange-dyed paper to the side of the eye. The stain helps with the examination and rinses out with tearing. The doctor uses a slit-lamp, which is moved forward toward the patient's face until the tonometer touches the eye.
The noncontact approach applies a puff of air and measures the force needed to indent the eye.

Attempting to close the eyelids during the test can increase eye pressure and produce errors in the results.

In general, normal IOP is usually maintained at measurements of 10 - 20 mm Hg. Glaucoma pressure over 21 mm Hg indicates a potential problem. The test is not completely accurate, however. Only about 10% of people with IOP levels between 21 - 30 mm Hg will actually develop glaucoma and optic nerve damage. On the other hand, many people with glaucoma have normal pressure, at least for part of the time.

Changes in posture may also affect IOP. A 2006 study indicated that IOP increases during sleep or when a person is lying down. As IOP tests are generally given in a doctor’s office when a patient is sitting up, they may not provide a completely accurate evaluation of eye pressure.

The cornea thickness may be an important indicator of disease progression in patients with elevated IOP. According to some research, patients with thinner corneas have a significant risk for developing damage from glaucoma, while those with thicker corneas have a low risk.

In order to determine early damage in the optic nerve, a number of diagnostic instruments have been developed to assess the nerve fiber layers at the back of the eye (the fundus) and to check for optic disk cupping. (The cup of the optic disc is the center portion, which enlarges as nerve damage progresses.) The two most common procedures for identifying nerve damage are ophthalmoscopy and fundus photography. Other instruments have been developed, including those that use laser technology and computers, but none have proved to be infallible. No test has proven to be completely accurate, however, and none is routinely performed by all eye professionals.

In order to be accurate, the tests require a skilled professional and there are certain common factors:

The pupils must also be widely dilated using eye drops before the procedure.
Even mild cataracts and a slightly less-than-optimally dilated pupil can degrade the results. Such conditions are common in elderly people, who are the most likely to develop glaucoma.
If the back of the eye is lightly pigmented (colored), the area under observation is less distinct.
If the glaucoma is diffuse and there is a generalized loss of nerve fiber (which occurs in half of patients), it is more difficult to detect than if the glaucoma is more localized.

If IOP is low or normal and tests report optic nerve damage and peripheral visual loss, doctors should also check for other conditions before starting any treatment for glaucoma. Such problems include steroid use, anemia, and previous hemorrhage or severe low blood pressure.

Ophthalmoscopy. The eye professional (or even a primary care doctor) uses an ophthalmoscope to peer through the pupil directly at the optic nerve. The examiner can then check the shape and color of the nerve fibers to evaluate whether they have been damaged by the high pressure of glaucoma. Damaged nerve fibers may be indicated by:

An asymmetrical or elongated cupped optic nerve
The optic nerve color may be pale or an unhealthy-pink

If results show no optic nerve damage in patients who have mild elevations in pressure, the ophthalmologist may want to retest frequently but delay drug treatment, unless the patient has significant risk factors.

Fundus Photography. Fundus photography may be used to take pictures of the optic nerve and can reveal changes years in advance of vision loss. It is an unpleasant procedure requiring drops and a bright flash. This procedure has the same limitations as ophthalmoscopy.

Laser Polarimetry. Polarimetry uses laser technology to scan the eye and does not require any response from the patient. It is reported to be able to measure nerve fiber thickness in the eye and so be able to reveal early signs of deterioration. Preliminary studies have indicated that it has a diagnostic accuracy of over 90% for both confirming and ruling out glaucoma. One study, however, reported that laser polarimetry was sensitive enough to detect glaucoma in only up to 57% of patients with early glaucoma, 71% of those with moderate disease, and 81% of those with severe glaucoma. More research is needed.

Other Devices. Computer-assisted devices, such as the confocal scanning laser ophthalmoscope, are now available that may be useful for evaluating the retinal nerve layer. Another instrument, the optical coherence tomograph, measures the echo time delay of light that is scattered back from different layers in the retina. The value of these tests has not yet been determined.

If there is indication of optic nerve damage, the eye professional will conduct tests of the visual fields (the areas that the patient can see). In most people with glaucoma, the first areas to become noticeably impaired are the peripheral visual fields (areas of sight that are not directly in front of a person but more to the sides).

Click the icon to see an image of the visual field test.

Standard Perimetry Tests. Perimetry tests are used to check peripheral vision. One variation of this test is as follows:

A person sits closely facing a large computer-like monitor.
Small bright white lights flicker on and off hundreds of times, at different places on the screen, while the patient clicks a button whenever one of the lights is seen.
The machine prints out a report that maps any blanked-out areas in the person’s vision.

The test is complex and lengthy; elderly people and those with short attention spans may be inappropriate candidates. Other perimetry tests, some requiring less time to administer and some using "virtual reality" techniques, are currently being developed.

Other Tests. Other visual field tests are being developed that can detect abnormalities years before they can be detected by standard perimetry. Experts recommend some of these tests in selected patients with suspected glaucoma.

For example, a screening test called frequency doubling technology (FDT) checks for changes in particular cells in the retina that are indications of early glaucoma. It takes less than a minute to perform.

Another test called short wave automated perimetry (SWAP) uses colors (blue-on-yellow) and also detects very early abnormalities in the visual field. Testing time is longer than with FDT, however, and the presence of certain types of cataracts can interfere with its accuracy.

ELAM-1. Endothelial leukocyte cell adhesion molecule 1 (ELAM-1) is a molecule that has been found in glaucoma but not in healthy eyes. This molecule may prove to be a "marker" and its presence may be helpful in diagnosing glaucoma.

A simple test using a penlight helps determine the risk for acute closed-angle glaucoma. A beam of light is directed from the side of the face toward the patient's iris. If no shadow appears on the nose, then most likely the angle is wide enough to dilate. Using an instrument called a gonioscope, ophthalmologists can also inspect the front of the eyes and assess the drainage angle between the cornea and the iris and the channels in the trabecular meshwork. This test can differentiate between closed- and open-angle glaucoma.

Treatment

Most treatments for glaucoma aim to reduce ocular pressure and its fluctuations. Early treatment with medications, surgery, or both can nearly always maintain safe pressure of the aqueous humor, thus preventing optic nerve damage and blindness. The choice between surgery and medications and when to start treatment is not always straightforward. For example, with the introduction of beta blockers and newer glaucoma drugs, there has been a decline in surgeries. It is not clear, however, which drugs are more effective than others and if, over time, any will actually prevent surgery. Patients should discuss all issues with their doctors and ophthalmologists.

Many people have high IOP but no sign of nerve damage. Over the course of 20 years, only between 10 - 30% of these people will actually develop glaucoma. Nevertheless, once glaucoma has destroyed optic nerve fibers, no known treatment can reverse the damage.

Indeed, studies suggest that in people with glaucoma, even very small differences in pressure may mean the difference between disease progression and stability. An important trial reported that, on average, treating patients when their glaucoma was first detected reduced IOP by 25%. In addition, treatment reduced the risk for progression by 17%. This study confirmed previous findings supporting early treatment for glaucoma. Another study found that treatment with eye drops halved the risk of developing open-angle glaucoma in African Americans who had elevated IOP. Some evidence suggests that early treatment to lower IOP may be beneficial even in patients with normal tension glaucoma.

However, not all individuals with early signs of glaucoma (elevated IOP or normal-tension glaucoma) develop optic nerve damage and serious vision problems. Nor does treatment prevent progression in a large minority of patients. Medications used for glaucoma also can carry significant side effects and risks.

Some experts suggest that treatment is warranted only in people with early signs of glaucoma who have risk factors for progressive disease and vision loss (thinner corneas, larger cup to optic disc ration, older age, and elevated pressure).

A number of effective drugs are now available for treating glaucoma. The drugs reduce pressure in the eye but all have a number of side effects that affect other parts of the body. Some of these side effects can be quite severe. Many of the drugs used for glaucoma also interact with common medications for other conditions. To compound the difficulties, many patients require multiple drugs. As a result, only about half of patients comply with their treatments.

Experts generally recommend topical drugs first (those that can be used as eye drops or ointments rather than taken by mouth).

Topical beta blockers are the standard first-line drugs, most commonly timolol (Timoptic). Newer beta blockers include betaxolol (Betoptic), levobunolol (Betagan), carteolol (Ocupress), and metipranolol (OptiPranolol). Timolol has been used for years, and these other drugs are also well tolerated.
Topical prostaglandins are alternatives if beta blockers fail. They include latanoprost (Xalatan) and unoprostone (Rescula). Of the standard drugs used for glaucoma, these drugs have the greatest effect on lowering IOPs. They also have fewer widespread effects than the beta blockers.
Topical carbonic anhydrase inhibitors (CAIs) are less effective than standard beta blockers or prostaglandins but have fewer widespread effects than the beta blockers. They may be helpful in certain cases. Topical forms are dorzolamide (Trusopt) and brinzolamide (Azopt). (Oral CAIs are available and more effective, but they have severe side effects and are rarely used for the long term.)
Alpha2-adrenergics, also called selective alpha adrenergics, are effective but may not be as well tolerated as timolol. They include brimonidine (Alphagan).
Miotics, which include pilocarpine and others, were the standard drugs before the introduction of topical beta blockers. They have now been largely replaced by timolol and others, although they are sometimes used in combinations.
Beta blockers and newer drugs (prostaglandins, topical CAIs, and selective alpha adrenergics) are now preferred over the older drugs, which include miotics, oral CAIs, and nonselective alpha adrenergics.

Combinations. Combinations of these drugs can be very effective, because they tend to have different actions. Single medications that contain two drugs are becoming available. For example, Cosopt combines timolol and dorzolamide; Timpilo is a combination of timolol and pilocarpine. Studies of these and other combinations compared to each other to single drugs are ongoing. To date, results on any superior combinations have been mixed. It should be noted that the side effects of each drug apply to any combination.

Treating the Pregnant Patient. Considerations for a pregnant woman with glaucoma can be complicated. All of the drugs used for glaucoma are absorbed by the body, cross the placenta, and are excreted in breast milk. Many have effects that can interfere with or adversely affect pregnancy.

Women should discuss going off medication, particularly during the first trimester, and be monitored during that time for increasing eye pressure. IOP tends to drop during pregnancy, although usually not to a significant degree. In addition, changes in IOP and visual loss vary greatly. Some women experience no IOP change or visual loss during pregnancy, while others may experience an increase in IOP or worsening of visual loss. It is important that your ophthalmologist carefully considers your individual case and discusses with you the risks and benefits of continuing glaucoma medication during pregnancy.

If women need to take medications, they should try to achieve the lowest dose possible. Some drugs have fewer side effects than others. Pregnant women must also be very careful about administering eye drops to allow as little medication as possible to enter the body. When taking eye drops, press your index finger against the corner of the eye near your nose. This helps prevent the eye drop from passing down into the tear duct where it is easily absorbed through the rest of the body. Even this approach, however, does not guarantee complete safety. Women with glaucoma who are planning to become pregnant might want to consider surgery before they conceive.

The object of standard glaucoma surgery is to reduce pressure in the eye by increasing the outflow of the aqueous fluid. Two methods are commonly used:

Filtration surgery (trabeculectomy). This uses standard surgical instruments to open a passage in the eye for draining fluid.
Laser trabeculoplasty. This procedure uses a laser to burn 80 - 100 tiny holes in the drainage area.

Both are effective, but certain patient groups may respond to one more than the other. For example, African Americans may do better with laser surgery while trabeculectomy may be a better choice for Caucasians with no serious medical problems.

In general, surgery is a last resort. Doctors may, however, recommend surgery before drug therapies for patients unlikely to comply with difficult drug regimens or for patients who may have severe reactions from the glaucoma drugs. Women who plan on becoming pregnant should also discuss surgery with their doctor.

Some studies indicate that laser treatment performed as the initial treatment for glaucoma is as effective as medications in some cases. Findings in 2003 from a major comparison study suggested that 4 years after surgery there was little difference in visual field loss between trabeculectomy and medical treatment. There was, however, a higher risk for cataracts and loss of vision sharpness with surgery. On the other hand, side effects from medications may be ongoing and troublesome. It is important to note that even surgery does not cure glaucoma, and over half of patients will require medication within 2 years. Experts who are against early surgeries also argue that studies on their success often omitted serious postoperative problems, such as late-onset infection, and quality of life assessments.

Medications

Nearly all glaucoma medications are prescribed for reducing eye pressure. Lowering IOP is even proving to be beneficial for about two-thirds of patients with normal-pressure glaucoma.

Topical beta adrenoceptor blockers (common called beta-blockers) are the drugs most often prescribed to treat glaucoma. They lower the pressure inside the eye by inhibiting the production of aqueous humor.

Brands. These drugs are categorized as either nonselective or selective beta-blockers:

Nonselective adrenoceptor beta-blockers. Timolol (Timoptic, Betimol) has been the standard beta-blocker for years. Newer nonselective drugs include levobunolol (Betagan), carteolol (Ocupress), and metipranolol (OptiPranolol). A few studies suggest some are more beneficial than timolol with similar side effects.
Selective beta1-adrenoceptor blockers. Betaxolol (Betoptic) and levobetaxolol (Betaxon) are selective beta-blockers. These drugs appear to have fewer adverse effects on the heart than the nonselective beta-blockers, although they still have widespread effects. Studies also suggest that they slow progression more than timolol, although timolol is more effective at lowering IOP. selective beta-blockers may also have nerve-protecting properties.

All beta-blockers are effective and generally well tolerated. Because they cause less eye irritation than many other glaucoma medications, they are often prescribed for patients who also have cataracts.

Side Effects and Complications. After the beta-blocker is administered, only a tiny amount of the drug is absorbed by the cornea. Most of it enters in the bloodstream. These drugs, therefore, can cause side effects in parts of the body other than the eyes ("systemic" side effects):

Common systemic side effects include reduced sexual drive, fatigue, depression, anxiety, severe nausea and vomiting, and breathing difficulties.
Beta-blockers affect the heart. They lower heart rate and reduce blood pressure. (The newer selective beta-1 blockers may not have as bad effects on the heart as the nonselective beta-blockers.) They may also cause unhealthy cholesterol and triglyceride changes.
All beta-blockers can worsen severe asthma or other lung diseases. Beta-blockers should only be used very cautiously or not at all by anyone with asthma, emphysema, bronchitis, or heart disease. In one study, lung function was reduced in 40% of elderly people who took timolol, even those without previous symptoms of lung problems. (Selective beta-blockers may produce fewer of these adverse effects.)
If the patient is switching to a beta-blocker from other glaucoma medication, there may be a sudden rise in eye pressure. It is important that the pressure be checked shortly after the other drug has been withdrawn.
When beta-blockers are used to treat one eye, the other (contralateral) eye also experiences a lesser, but still significant reduction in IOP.

Interactions with Other Medications. The effects of the eye medication may be additive to other oral medications, such as oral beta-blockers, calcium-channel blockers, or the antiarrhythmic drug quinidine. People with diabetes who take insulin or hypoglycemic medications should realize that timolol side effects may resemble and mask the symptoms of hypoglycemia (low blood sugar).

Prostaglandins are hormone-like substances that help open blood vessels. Drugs that resemble prostaglandins increase outflow of aqueous humor (the watery substance in the eye). Drainage of aqueous humor helps reduce intraocular pressure.

Brands. Latanoprost (Xalatan) and unoprostone (Rescula) are the standard brands. Latanoprost was the first prostaglandin to be approved as first-line treatment for elevated eye pressure. Two newer prostaglandins, travoprost (Travatan) and bimatoprost (Lumigan), may help some patients who do not respond to latanoprost. These drugs may also benefit patients with normal-tension glaucoma. Latanoprost, travoprost, and bimatoprost need to be taken only once daily. Unoprostone needs to be taken twice a day and is not as effective as others, but it still can reduce IOP significantly and is the least expensive of these drugs.

Latanoprost has been shown to reduce pressure by between 45 - 70%. Some, but not all studies, have suggested that newer prostaglandins travoprost (Travatan) and bimatoprost (Lumigan) are more effective than latanoprost, but the older drug appears to be better tolerated. All of these drugs may be work better than timolol in lowering IOP. The newer prostaglandins may be especially superior to timolol in treating African American patients. In comparison studies, latanoprost achieved better IOP pressure reduction than brimonidine. Studies have suggested that bimatoprost is more effective in lowering eye pressure than a combination of timolol and dorzolamide (Cosopt). Studies have been mixed on whether latanoprost is superior to the combination.

Side Effects. These drugs do not slow down the heart rate and also appear to be safe for people with asthma. Side effects include itching, redness, and burning during administration. Muscle and joint pain may also occur. All of these drugs may permanently change eye color from blue or green to brown. To date, such color changes do not seem to be hazardous. (The only significant problem may be cosmetic in people who treat only one eye, since the color may differ from the other.) These drugs can increase blood flow in the eye and also make eyelashes become thicker and longer in some patients. (These latter effects are more common with bimatoprost and travoprost than with latanoprost.)

Carbonic anhydrase inhibitors (CAIs) decrease eye pressure by reducing the fluid in the chambers of the eye (aqueous humor). Research suggests that CAIs reduce aqueous humor fluid by as much as 40%. These drugs are used for glaucoma when other drugs do not work. They may be combined with other medications.

CAIs may also improve blood flow in the retina and optic nerve (beta-blockers do not). Improving blood flow can keep the disease from getting worse.

Brands and Side Effects. CAIs are available in the following forms:

Eye-drop CAIs include dorzolamide (Trusopt) and brinzolamide (Azopt). About 10% of patients report fatigue, stinging in the eye, and loss of appetite using dorzolamide. Taste changes can occur. Research suggests that dorzolamide can be helpful for children with glaucoma, including those younger than 6 years old. Brinzolamide is a newer medication that was chemically designed to be closer in pH to human tears and may cause less stinging than dorzolamide.
Oral forms include acetazolamide (Diamox), methazolamide (Neptazane), and dichlorphenamide (Daranide). Although they are more effective than eye drops, they have significantly more side effects and are rarely used for long-term treatment. The oral forms have very unpleasant side effects that include frequent urination, depression, stomach problems, fatigue, weight loss, sexual dysfunction, and, in infants, failure to thrive. Long-term use of the oral forms, in rare cases, can cause serious anemia and kidney problems, including the risk for stones. They can also produce a toxic reaction when taken with large doses of aspirin.

Adrenergic agonists activate muscles in the eye that dilate pupils and, therefore, increase outflow of aqueous fluid. Newer variations called alpha 2-adrenergic agonists reduce production of aqueous humor and also increase outflow through the uveoscleral pathway (the alternative channel to the trabecular meshwork). Older adrenergic agonists include epinephrine.

Alpha 2-Adrenergic Agonists. Apraclonidine (Iopidine) and brimonidine (Alphagan) are alpha 2-adrenergic agonists. These have generally been used before glaucoma surgery, but a number of studies are indicating that they may even be useful as primary therapy when used in combination with beta-blockers or other standard drugs.

Brimonidine is proving to be particularly effective for long-term therapy. (Apraclonidine is used for the short term.) It also may have nerve-protecting properties and may be safer than other drugs during pregnancy and for patients with asthma.

The most common side effects of brimonidine and apraclonidine are dry mouth and altered taste. They also commonly trigger an allergic reaction that causes red and itching eyes and lids, a major drawback. Brimonidine causes less of an allergic response than apraclonidine. Unlike apraclonidine, however, it can cause lethargy and mild low blood pressure. It also appears to remain effective longer.

Miotics, also called cholinergic agonists, narrow the iris muscles and constrict the pupil. This action pulls the iris away from the trabecular meshwork and allows the aqueous humor to flow out through the drainage channels, reducing the pressure inside the front of the eye.

Brands. Pilocarpine (Pilocar, Adsorbocarpine, Almocarpine, Isoptocarpine, Ocusert) was the most widely used anti-glaucoma drug before timolol was introduced. It is the preferred miotic. Because pilocarpine is used up by the body fairly quickly, however, patients must take it several times a day; many people, therefore, fail to take their medication regularly. A combination of timolol or latanoprost with pilocarpine is more effective than either drug used alone. Carbachol is another miotic.

Demecarium (Humorsol), isoflurophate (Floropryl), and echothiophate (Phospholine) are a group of long-acting drugs known as anticholinesterase miotics. Because of their potential for serious side effects, however, some authorities even prefer surgery to their use.

Epinephrine and its derivatives are the older anticholinergics. Epinephrine is now rarely prescribed because of side effects. Dipivefrin (Dipivefrin), a newer form of epinephrine, remains inactive until it reacts with enzymes in the cornea. It is effective in low doses and causes few systemic side effects.

Side Effects. Side effects include:

Teary eyes, brow-aches, eye pain, and allergic reactions.
A miotic narrows the pupil and so can cause nearsightedness. Vision can also become dim and it may difficult to see in darkened rooms or at night, when driving could be hazardous. A gel form administered once a day or wafer placed under the lid once a week may help reduce these side effects.
The anticholinesterase miotics increase the risk of cataract development and are therefore used mostly in patients in whom cataracts have already been removed. Retinal detachment is an uncommon but dangerous side effect in susceptible individuals. Excessive use of these miotics may cause toxic reactions, including convulsions, muscular paralysis, and even death from respiratory failure.
Epinephrine can produce burning in the eyes, enlarged pupils, and allergic reactions. Occasionally it can cause anxiety and headaches. Rare side effects include high blood pressure and disturbances in heart rhythm. It is rarely prescribed now. Although dipivefrin, the newer form of epinephrine, has fewer systemic side effects, it still causes problems in the eyes similar to those of epinephrine.

Cannabinoids. Cannabinoids, compounds in marijuana (cannabis), are being studied for their effects on glaucoma. For example, oral or inhaled tetrahydrocannabinol (THC), the active ingredient in marijuana, has been shown to reduce IOP in 60 - 65% of patients. The effects of smoking marijuana on IOP last only 3 hours, however. THC also increases the release of glutamate -- a nerve-protecting chemical. Experts are hoping that topical use of THC or other cannabinoids may help prevent optic nerve damage without the widespread effects of oral or inhaled administration.

Reasons for Noncompliance. Studies indicate that more than 40% of patients miss 10% of their doses, and 15% of patients miss more than 50% of their doses. Noncompliance is very high for many reasons:

People with chronic glaucoma who are on medication must use eye drops or take pills one or more times a day, usually for the rest of their lives.
Many people require a multi-drug regimen, two or more different kinds of medications that can be used in various combinations, such as eye drops, ointments, or time-release wafers inserted under the eyelid. Such regimens can be very confusing.
The side effects of the drugs are more unpleasant than the disease itself, which has no symptoms until vision is lost. Because the treatment does not usually produce any noticeable improvement, the consequence of not taking the drugs (blindness) may seem far in the future.
Skipping even a few doses can greatly increase the risk of visual loss. It is essential that patients tell their doctor if they are not regularly taking their medication. Otherwise, the doctor may increase the dosage, thereby causing unwelcome side effects.

Patients who do not regularly take their glaucoma medication are at high risk for blindness. If you have problems taking your medications or sticking to the dosing regimen, talk with your doctor.

Hints for Managing a Regimen.

Pharmaceutical manufacturers use colored tops, yellow for timolol, for example, and green for pilocarpine, to help prevent mix-ups. Creating a chart scheduling each drug by color can be helpful.
Small electronic timers are available that will signal times for taking the medications. The timing of these combinations is important. For example, the combination of pilocarpine with latanoprost is most effective when pilocarpine is taken four times a day and when the bedtime dose is administered an hour after latanoprost.
Some patients may be candidates for single medications that combine two drugs, such as Cosopt, which contains both dorzolamide and timolol. This medication requires only one drop twice per day. Patients who need additional glaucoma drugs, however, will need to take these two drugs separately.
When using any drug for a long period of time, side effects are a potential problem. If they become intolerable, patients should discuss with the doctor reducing the dosage or trying other drugs.

Administering Eye Drops. A common reason that medicine does not work is that patients do not take it correctly. Patients should ask the ophthalmologist to watch while they place the drops in their own eyes to make sure the procedure is being done correctly. The following are some recommended steps:

If you use both ointments and eye drops, take the eye drops first.
Wash your hands before applying eye drops.
Hold the bottle upside down.
Tilt your head back and, with one hand, pull the lower eyelid down to form a pocket.
With your other hand, hold the bottle as close as possible to your eye. Don’t let the bottle directly touch your eye or eyelid.
After you have placed the drop, close your eye or press your index finger against the corner of the eye near your nose. Gently move the lower lid upward until the eye is closed. Keep your eye closed for at least 1 minute. This prevents the drop from draining out.
Wait at least 5 minutes before applying another drop or a different medication

In this emergency situation, ophthalmologists may administer a combination of two or more anti-glaucoma medications to reduce eye pressure quickly before it can damage the optic nerve and cause visual loss. Apraclonidine (Iopidine) is a powerful drug used before and after laser surgery to prevent an increase in fluid pressure and is more effective than other medications. In addition to standard drugs, doctors may also administer glycerin (Glyrol, Osmoglyn) by mouth or mannitol or acetazolamide intravenously. Surgery is almost always performed once the pressure is reduced.

Most rare forms of glaucoma respond to the same medications and surgery used for open angle glaucoma. Irido corneal endothelial syndrome (ICE) is difficult to treat and if surgery is required, filtering surgery is the best choice. Neovascular glaucoma is also very hard to treat; researchers are investigating drainage implants for this disorder.

Surgery

If medications do not control eye pressure, or if they create intolerable side effects, surgery may be necessary in a small percentage of people with chronic glaucoma. It may be particularly helpful for patients with pseudoexfoliation glaucoma.

The standard procedures are usually one of the following:

Filtration surgery (trabeculectomy). This procedure opens the full thickness of the drainage area.
Laser trabeculoplasty. This procedure partially opens the drainage area. It does not reduce pressure to the extent of trabeculectomy but it has fewer adverse effects.

African Americans may respond better to initial laser surgery than to conventional trabeculectomy, while the opposite may be true in Caucasians. Some experts now recommend that, in most circumstances, African Americans should start with laser surgery and Caucasians who have no serious medical problems should have trabeculectomy first.

In addition, a number of experimental and less invasive procedures are under development.

The Procedure. Filtration surgery has been used for more than 100 years with only minor modifications. It employs conventional surgical techniques known as full-thickness filtering surgery or guarded filtering surgery (trabeculectomy).

The surgeon creates a sclerostomy, a passage in the sclera (the white part of the eye) for draining excess eye fluid.
A flap is created that allows fluid to escape but which does not deflate the eyeball.
The surgeon may also remove a tiny piece of the iris (called an iridectomy) so that fluid can flow backward into the eye.
A small bubble called a bleb nearly always forms over the opening, which is a sign that fluid is draining out. Although surgeons aim for a thick bleb, which poses less risk than a thin one for later leakage, paradoxically the ideal operation would have no bleb at all.

The procedure has a high success rate. About 50% of patients no longer need medication after surgery. Thirty-five to 40% of those who still need medication have better control of their glaucoma.

A new instrument called a trabectome has allowed for a less invasive type of trabulectomy surgery The trabectome procedure appears to be a safe and simple way to lower eye pressure. It can be performed before a traditional trabulectomy, if needed. Results from a small study, presented at the 2005 meeting of the American Academy of Ophthalmology, showed that the new approach successfully reduced eye pressure in 90% of patients with open-angle glaucoma.

Side Effects. Many of the serious side effects or complications that occur with filtration surgery involve blebs (blister-like bumps).

Bleb Leaks and Infections. Blebs, particularly thin ones, commonly leak. Leakage can occur early on or sometimes as late as months or years after surgery. Untreated, such leaks can be serious and even cause blindness. Late-onset leakage significantly increases the risk for infection as well as a number of other serious conditions, including bleeding, a flattening of the eye ball, and harmful inflammation. Surgical repair is the most effective way of managing leaking blebs, although drug therapies, pressure patching, and other nonsurgical techniques may be tried first. Due to the dangers of leaking blebs, experts recommend lifelong monitoring after surgery. Unfortunately, the incidence of late-onset leaking blebs is increasing due to the use of drugs used in filtration surgery to prevent scarring, another complication.
Scarring. In up to 20% of cases, scars form around the incision, closing up the drainage channels and causing pressure to rebuild. These scars are formed from fibroblasts, which are immature collagen cells that form at the surgical site. Scarring is a particular problem in young patients, African Americans, patients who have taken multiple drugs, have had an inflammatory disease, or have had cataract surgery. Releasing the surgical stitches used in the procedure may help prevent scarring and pressure build-up. A second procedure called bleb needling sometimes can open up the scarred area and restore drainage. With this technique, the tip of a very fine hypodermic needle is used carefully to cut loose the particles closing off the drainage area. A new technique that does not require sutures may prove to be effective and have fewer complications.
Cataracts. The procedure is highly associated with the development of cataracts over time. Because cataracts are associated with glaucoma anyway, it is not entirely clear whether the cataracts are caused by the surgery or would develop in any case.

Click the icon to see an illustrated series detailing cataract surgery.

Supportive Medication for Preventing Scarring. Specific drugs, usually mitomycin C, are often used in conjunction with the procedure to prevent scarring and closure. A large review of studies of mitomycin C supported its effectiveness in increasing surgical success in nearly all patients. Fluorouracil (5-FU) appears to be similar in effectiveness but has a high risk for complications and is not used as often as in the past.

The Procedure. Laser trabeculoplasty involves the following steps:

The procedure uses an instrument, usually a YAG laser, to burn 80 - 100 tiny holes in the drainage area.
A tiny scar forms, which increases fluid outflow.
The procedure takes 15 minutes, causes almost no discomfort, and has very few complications.

In a 2-year study, laser surgery of the trabecular meshwork reduced pressure by a third in 70 - 97% of patients. Patients still need to take anti-glaucoma eye drop medications every day.

Laser surgery is not a cure. Within 2 - 5 years, about half of patients need either additional surgery or new medications.

Complications. In about 35% of patients, pressure increases after surgery. In most cases it is temporary, but in rare cases the increased pressure is permanent and vision loss can occur. Use of the drug apraclonidine (Iopidine) or pilocarpine can help prevent this elevated pressure. About a third of patients also develop adhesive-like substances called peripheral anterior synechiae that cause the iris to stick to part of the cornea.

Drainage implants, also known as tube shunts, may be used to drain fluid in certain cases, such as if glaucoma is not responsive to any standard procedure or is caused by certain conditions. A 2007 study suggested that tube shunts work better than filtration surgery (trabulectomy) for some patients. In the study, patients who received tube shunts had more stable IOP over the course of a year than patients who underwent trabulectomy.

Candidates. Success rates are highest (75% pressure control over 5 - 7 years) in appropriate patients. Drainage implants may be useful in the following conditions:

Glaucoma caused by swelling in the iris
Glaucoma caused by abnormal vessel formations
Iridocorneal endothelial (ICE) syndrome

The Procedure. In general, the procedure involves:

An implant, most commonly a 1/2 inch silicone tube, is inserted into the eye's front chamber (anterior). The Molteno implant used with mitomycin C is currently the most effective approach, with reported success rates of 80%. Other implants, such as the Ahmed implant, may have fewer complications.
The tube drains the fluid onto a tiny plate that is sewn to the side of the eye.
Fluid collects on the plate and then is absorbed by the tissues in the eye.

Complications. Complications include:

Hypotony (very low eye pressure) is a serious complication that has been reduced using better techniques and improved implants.
Cataracts, detached retina, breakdown of the cornea, and bleeding are potentially significant complications.
There is also a risk for eye movement disorders, such as strabismus (crossed eyes) or diplopia (double-vision).

The implant often becomes blocked and repeated operations are needed. Some researchers are studying the use of a drug called tissue plasminogen activator (tPA) to open up tubes that have been blocked by blood or blood factors. (This so-called clot-busting drug is normally used to break up blood clots during heart attacks.) In one 2002 study, tPA prevented such blocks in 89% of eyes. Unfortunately, significant complications rates were high (11%).

Deep sclerectomy and viscocanalostomy are less invasive techniques than filtering surgery that leave the anterior chamber (front of the eye) intact and avoid creation of blebs.

In deep sclerectomy, the surgeon removes a deep piece of the sclera (the white part of the eye), part of the trabecular meshwork, and the front of Schlemm's canal (the vessels that return fluid into the bloodstream).

In both deep sclerectomy and viscocanalostomy, the surgeon first creates a flap in the outer part of the sclera (the white part of the eye) and then removes a deep piece of the sclera underneath. This opens up Schlemm's canal (the vessels that return fluid into the bloodstream) and exposes a layer above the anterior chamber called Descemet's membrane. A space has also been created between the inner and outer layers of the sclera.
In deep sclerectomy, this space now serves as a tiny reservoir for aqueous fluid that flows through the membrane and pools here. The fluid then flows out without the surgeon having to open the anterior chamber (as in standard filtering surgery).
In viscocanalostomy, the surgeon typically injects gel-like materials into the ends of Schlemm's canal in order to enlarge the canal for fluid outflow and lower IOP. The tiny reservoir is sewn tightly up.

Many variations are under investigation. In general, the procedures have fewer complications afterward than standard filtering surgery, although they require excellent surgical skill. Nonpenetrating techniques do not lower IOPs as much as conventional surgery does, however. In time, however, these nonpenetrating techniques are expected to be as effective as filtration surgery.

Cataracts and Glaucoma. For patients with both glaucoma and cataracts, experts recommend the following:

In patients with cataracts and poorly controlled glaucoma, a two-step procedure for both eye conditions is needed. Typically the patient will first have a trabeculectomy for glaucoma, followed by cataract surgery such as phacoemulsification (lens removal through ultrasound). Fluid leakage and the presence of blood in the back chamber of the eye are potential complications of this combined procedure.
Phacoemulsification is sometimes combined with viscocanalostomy in a procedure called phacoviscocanalostomy. A 2006 study suggested this approach is safe and effective. The study followed patients for 7 years after they underwent phacoviscocanalostomy and found that no serious complications occurred.
In patients who have cataracts plus either closed-angle glaucoma or open angle glaucoma that is stabilized with medication, the cataract may be able to be extracted and medication continued for the glaucoma.

A major 2002 analysis suggested that the combined approach generally offers better control over eye pressure for patients with both cataracts and glaucoma. However, it is still unclear which specific type of surgical procedure works best. [See In-Depth Report #26: Cataracts.]

Diode laser transscleral cyclophotocoagulation (TSCPC), also called laser cycloablation, reduces aqueous production by destroying the muscles that control the lens for near and far vision (the ciliary body ). There is a chance of vision loss with this procedure, so it is reserved for people with end-stage glaucoma or those who fail to benefit from any other therapies. Nevertheless, researchers continue to explore the possibilities for this effective procedure, especially for people who may not have access to expensive medications. Studies have suggested it may even be suitable as first-line surgery for some patients.

For an acute closed-angle glaucoma attack, emergency microsurgery is usually necessary after reducing pressure with medications.

Iridotomy or Iridectomy. Either laser (iridotomy) or conventional (iridectomy) surgery may be used. With either procedure an ophthalmologist makes a tiny opening in the iris to let the aqueous humor flow out more freely. Because acute glaucoma commonly occurs later in the other eye, surgeons will often recommend surgery in the unaffected eye to prevent a second attack.

Laser iridotomy almost never requires hospitalization, and postsurgical treatment includes only aspirin and eye drops. It has almost completely replaced conventional surgery, which requires anesthesia and hospitalization.

Vision will be blurred, and recovery can take 4 - 8 weeks. Once surgery has been performed, such patients can usually use previously restricted anticholinergic medications, such as antihistamines and certain antidepressants, with safety.

Phacoemulsification and Intraocular Lens Implantation. Phacoemulsification and intraocular lens implantation, a procedure ordinarily used for cataracts, may prove to be beneficial for some patients with acute angle-closure glaucoma requiring surgery. [See In-Depth Report #26: Cataracts.]

Lifestyle Changes

Studies suggest that patients with glaucoma who exercise regularly (at least 3 times a week) may be able to reduce their intraocular pressure by an average of 20%. If they stop exercising for more than 2 weeks, pressure increases again. In one study, those who walked briskly 4 times a week for 40 minutes were able to go off their medications. (Although not confirmed by any evidence, yoga or other exercises that involve head-down or inverted positions may be harmful for patients with glaucoma and should be discussed with the doctor.)

Exercise has no effect on closed-angle glaucoma. It may, in fact, increase eye pressure in patients with pigmentary glaucoma. Vigorous high-impact exercise may cause more pigment to be released from the iris in these patients. Patients should talk to their doctor about an appropriate exercise program.

Antioxidants in Foods and Supplements. Diet most likely plays very little role in glaucoma. For example, a 2003 study found no association between important nutrients associated with protection against other eye disorders, including vitamins C, E, A, and carotenoids.

Caffeine. Some studies have shown that large amounts of caffeine drunk in a short period of time can elevate eye pressure for up to 3 hours. One study suggested that such changes in eye pressure could be significant in patients with both normal eye pressure and high IOP.

Fluids. Drinking large amounts (a quart or more) of any liquid within a short time, about 30 minutes, appears to increase pressure. Patients with glaucoma should have plenty of fluids, but they should drink them in small amounts over the course of a day.

Glaucoma can cause the eyes to be very sensitive to light and glare. Medications can worsen this problem. Sunglasses solve this problem and are important for prevention of cataracts. Protective sunglasses do not have to be expensive. Sunglasses are classified into three categories based on protection against ultraviolet radiation (UV) A or B:

Cosmetic-purpose sunglasses block at least 70% UVB and up to 60% UVA. People should avoid these glasses if they have any risk for cataracts or eye problems.
General-purpose sunglasses block at least 95% UVB and a minimum of 60% UVA. At the very least, people should purchase general purpose sunglasses and they should be labeled "Meets ANSI Z80.3 General Purpose UV Requirements.” Labels should indicate that sunglasses block UV radiation up to 400 nm.
Special-purpose sunglasses block at least 99% UVB and a minimum of 60% UVA rays. These are the optimal sunglasses for people at risk for eye disease. Special purpose glasses should wrap around the head and block light coming from above, below, and both sides of the glasses. They should also fit snugly on the nose.
Lenses that are simply dark but not coated with UV-absorbing material may increase the risk of cataracts because the pupil widens to compensate for the shaded glass. This may allow more harmful ultraviolet waves to enter the eye. Polarized glasses cut glare but have no effect on UV radiation. Mirror finishes without additional processing for UV blockage also are not fully protective. There is some controversy over whether blue light is harmful to the eyes. Some people prefer amber lenses, which block out the blue spectrum.

Meditation, biofeedback, and relaxation methods can help counteract stress, and there are some reports that they may help some people with open-angle glaucoma. A number of herbal and nontraditional remedies have been advertised as glaucoma remedies. A few studies have reported that the herbal remedy ginkgo biloba may have properties that offer benefits to patients with glaucoma, including increasing blood flow in the eye without altering overall blood pressure, heart rate, or intraocular pressure. More research is, however, needed.

Generally, manufacturers of herbal remedies and dietary supplements do not need FDA approval to sell their products. Just like a drug, herbs and supplements can affect the body's chemistry, and therefore have the potential to produce side effects that may be harmful. There have been a number of reported cases of serious and even lethal side effects from herbal products. Always check with your doctor before using any herbal remedies or dietary supplements.

The following is of special concern for people with glaucoma:

Bilberry, a European blueberry (Vaccinium myrtillus), is sold in natural food stores as a glaucoma remedy. Studies indicate that it may help some people improve night vision and glare, but it is not at all effective in preventing or treating glaucoma.

Resources

www.glaucoma.org -- Glaucoma Research Foundation
www.nei.nih.gov -- National Eye Institute
www.glaucomafoundation.org -- The Glaucoma Foundation
www.aao.org -- American Academy of Ophthalmology
www.glaucomaweb.org -- American Glaucoma Society
www.lighthouse.org -- Lighthouse International

References

Bottaro M, Ritch R. Intraocular pressure variation during weight lifting. Vieira GM, Oliveira HB, de Andrade DT. Arch Ophthalmol. 2006 Sep;124(9):1251-4.

Brauner SC, Chen TC, Hutchinson BT, Chang MA, Pasquale LR, Grosskreutz CL. The course of glaucoma during pregnancy: a retrospective case series. Arch Ophthalmol. 2006 Aug;124(:1089-94.

Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL. Treatment outcomes in the tube versus trabeculectomy study after one year of follow-up. Am J Ophthalmol. 2007 Jan;143(1):9-22.

Hara T, Hara T, Tsuru T. Increase of peak intraocular pressure during sleep in reproduced diurnal changes by posture. Arch Ophthalmol. 2006 Feb;124(2):165-8.

Higginbotham EJ. Managing glaucoma during pregnancy. JAMA. 2006 Sep 13;296(10):1284-5.

Pasquale LR, Kang JH, Manson JE, Willett WC, Rosner BA, Hankinson SE. Prospective study of type 2 diabetes mellitus and risk of primary open-angle glaucoma in women. Ophthalmology. 2006 Jul;113(7):1081-6.

Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006 Mar;90(3):262-7.

Wishart MS, Dagres E. Seven-year follow-up of combined cataract extraction and viscocanalostomy. J Cataract Refract Surg. 2006 Dec;32(12):2043-9.

Review Date:
3/3/2007
Reviewed By:
Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

A.D.A.M. Copyright

adam.com

Cataracts

FitSugar — Wed, 08 Oct 2008 17:35:39 -0700

In This Report

Highlights
Introduction
Causes
Symptoms
Prognosis
Risk Factors
Prevention
Diagnosis
Treatment
Resources
References

HEALTH GUIDE REFERENCE FROM A.D.A.M

Highlights

Medical Societies Issue Tamsulosin (Flomax) Warning

In August 2006, the American Society of Cataract and Refractive Surgery (ASCRS), the American Academy of Ophthalmology, and the American Urological Association (AUA) issued a joint warning concerning Tamsulosin (Flomax). The societies advised patients to be sure to inform their eye surgeons if they are taking this drug. Tamsulosin is frequently prescribed to treat prostate enlargement.

The ACSRS has developed specific cataract surgery techniques for cataract patients who take this drug. Recent research suggests that these new techniques produce successful surgical outcomes.
The AUA warns that while men are primarily at risk, more women may be at risk in the future as Tamsulosin is increasingly being prescribed for urinary retention.

Cost of Cataracts

Cataracts cost the United States nearly $7 billion a year in medical services and pharmaceutical costs, according to a 2006 report in the Archives of Ophthalmology.

Can Statins Reduce Cataract Risk?

Statin drugs, which are used to manage cholesterol levels, are associated with a lower risk of nuclear cataract -- the most common type of age-related cataract -- according to a 2006 study in the Journal of the American Medical Association. Researchers think that the antioxidant properties of statins may account for this association.

Cataract Surgery

A new surgical technique, phacoviscocanalostomy, works well for patients who have both glaucoma and cataracts, suggests a 2006 study in the Journal of Cataract and Refractive Surgery.
Newer methods of administering local anesthesia are resulting in fewer complications than older methods, indicates a 2006 study in the British Journal of Ophthalmology.

Intraocular Lenses (IOLs)

The Tecnis ZM001 IOL helped produce better reading clarity and reading speed than several other newer multifocal IOLs, according to a 2006 comparison study. Multifocal IOLs are used for patients who need correction for both farsightedness and nearsightedness.

Introduction

A cataract is an opacity, or clouding, of the lens of the eye.

The lens of an eye is normally clear. If the lens becomes cloudy or is opacified, it is called a cataract.

The prevalence of cataracts increases dramatically with age. It typically occurs in the following way:

The lens is an elliptical structure that sits behind the pupil and is normally transparent. The function of the lens is to focus light rays into images on the retina (the light-sensitive tissue at the back of the eye).
In young people, the lens is elastic and changes shape easily, allowing the eyes to focus clearly on both near and distant objects.
As people reach their mid-40s, biochemical changes occur in the proteins within the lens, causing them to harden and lose elasticity. This causes a number of vision problems. For example, loss of elasticity causes presbyopia, or far-sightedness, requiring reading glasses in almost everyone as they age.
In some people, the proteins in the lens, notably those called alpha crystallins, may also clump together, forming cloudy (opaque) areas called cataracts. They usually develop slowly over several years and are related to aging. In some cases, depending on the cause of the cataracts, loss of vision progresses rapidly.
Depending on how dense they are and where they are located, cataracts can block the passage of light through the lens and interfere with the formation of images on the retina, causing vision to become cloudy.

Click the icon to see an image of eye anatomy.

Cataracts can form in any of three parts of the lens and are named by their location.

Nuclear cataracts. These form in the nucleus (the inner core) of the lens. This is the most common variety of cataract associated with the aging process.
Cortical cataracts. These form in the cortex (the outer section of the lens).
Posterior subcapsular cataracts. These form toward the back of a cellophane-like capsule that surrounds the lens. They are more frequent in people with diabetes, who are overweight, or those taking steroids.

Causes

Although older age is the primary risk factor for cataracts, experts are still not certain about the exact biologic mechanisms that tie cataracts to aging.

Researchers have been focusing on particles called oxygen-free radicals as a major factor in the development of cataracts. They cause harm in the following way:

Oxygen free radicals (also called oxidants) are molecules produced by natural chemical processes in the body. Toxins, smoking, ultraviolet radiation, infections, and many other factors can create reactions that produce excessive amounts of these oxygen free radicals.
Oxidants are missing an electron, so they are unstable and tend to chemically bind with other molecules in the body. When oxidants are overproduced, these chemical reactions can be very harmful to nearly any type of cell in the body. At times these reactions can even effect genetic material in cells.
Cataract formation is one of many destructive changes that can occur with overproduction of oxidants, possibly in concert with deficiencies of an important protective anti-oxidant called glutathione.
Glutathione occurs in high levels in the eye and helps clean up these free radicals. One theory posits that in the aging eye, barriers develop that prevent glutathione and other protective antioxidants from reaching the nucleus in the lens, thus making if vulnerable to oxidation.

Sunlight and Ultraviolet Radiation. Sunlight consists of ultraviolet (referred to as UVA or UVB) radiation, which penetrates the layers of the skin. Both have destructive properties that can promote cataracts. The eyes are protected from the sun by eyelids and the structure of the face (overhanging brows, prominent cheekbones, and the nose). Long-term exposure to sunlight, however, can overcome these defenses.

UVB radiation produces the shorter wavelength, and primarily affects the outer skin layers. It is the primary cause of sunburn. It is also the UV radiation primarily responsible for cataracts. Long-term exposure to even low levels of UVB radiation can eventually cause changes in the lens, including pigment changes, which contribute to cataract development. (UVB also appears to be responsible for macular degeneration, an age-related disorder of the retina.) Some scientists suggest that global warming and ozone depletion may increase people’s exposure to UVB, leading to a greater incidence of cataracts.
UVA radiation is composed of longer wavelengths. They penetrate more deeply and efficiently into the inner skin layers and are responsible for tanning. The main damaging effect of UVA appears to be the promotion of the release of oxidants.

Radiation Treatments. Cataracts are common side effects of total body radiation treatments, which are administered for certain cancers.

Electromagnetic Waves. Questions have been raised about the hazards of low-level radiation from computer screens. To date, no study has demonstrated an association between cataract development and video display terminals. It is a good idea, in any case, to sit at least a foot away from the front of a screen.

Cataracts are one of the many ill effects caused by smoking. Many studies have implicated smoking in the development of nuclear cataracts. The major damaging effects of cigarette smoke appear to be enhancement of free oxygen radicals, the chemical byproducts in the body that can damage cells, including those in the eye.

Corticosteroids. Long-term use of oral steroids is a well-known cause of cataracts. Studies have been conflicting, however, over whether inhaled and nasal-spray steroids increase the risk for cataracts. Information on cataract risk from inhaled steroids is important because they are commonly used by asthma patients, and steroid spray use is increasing among allergy sufferers. Studies have suggested a higher risk for cataracts among middle-aged and elderly patients treated with beclomethasone (Beclovent, Vanceril). However, newer inhaled steroids are available, and their effects on the eye are unclear. In children, cataracts are rare, and the benefits of inhaled steroids for asthma far outweigh any small additional risk.

Other Medications Associated with Cataracts.

Psoralens, a class of drugs used along with light therapy to treat skin disorders, such as psoriasis
Antipsychotic medications such as chlorpromazine (Thorazine)
Glaucoma medications

Many others drugs have been weakly associated with cataracts, including allopurinol, tamoxifen, amiodarone, tricyclic antidepressants, potassium-sparing diuretics (but not other diuretics), thyroid hormone, tetracyclines, sulfamidase, and mepacrine. According to a 2006 study in the Journal of the American Medical Association, statin drugs (used for managing cholesterol) may possibly reduce the risk for nuclear cataracts.

Click the icon to see an animation about cataracts.

Glaucoma. Glaucoma and its treatments, including certain drugs (notably miotics) and filtering surgery, pose a high risk for cataracts. The glaucoma drugs posing a particular risk for cataracts including demecarium (Humorsol), isoflurophate (Floropryl), and echothiophate (Phospholine).

Uveitis. Uveitis is chronic inflammation in the eye, which is often caused by an autoimmune disease or response. Often the cause is unknown. It is a rare condition that carries a high risk for cataracts.

A number of medical conditions appear to be associated with a higher risk for cataracts either because of a direct effect or because of the medications used for them, or both. They include the following:

Diabetes. Cataracts in patients with diabetes appear to form when high levels of blood sugar react with proteins in the eye to form byproducts that accumulate in the lens (sugar cataracts).
High blood pressure (hypertension).
Autoimmune diseases including rheumatoid arthritis, psoriasis, multiple sclerosis, systemic lupus erythematosus, Behcet's disease, and others.

Rarely, about 1 in every 10,000 births, a baby is born with cataracts (called congenital cataracts).

Inherited disorders are often involved in the development of congenital cataracts in children. Such cataracts are most often due to inborn abnormalities in the structure or shape of the lens, including its capsule. Dozens of variations can affect the lens causing, susceptibility to cataracts. Researchers are also investigating genetic factors that may cause mutations in alpha crystallins -- major proteins in the lens, which form cataracts. (Genetic factors also may play a role in some adult cataract cases. The exact hereditary predispositions have yet to be established.)
Infection during pregnancy can lead to cataracts.
Pregnant women who abuse alcohol or drugs increase the risk for cataracts (along with other more serious birth defects) in their infants.

Surgery in children with early-onset cataracts can help correct this problem in many cases, but it should be performed as soon as possible for full benefit. Experts recommend routine examination of the face of a fetus during ultrasound for abnormalities.

Symptoms

During the early stages, cataracts have little effect on vision. The symptoms of a cataract may include:

Cloudy vision, double vision, or both may be the first signs.
Images may take on a yellowish tint as color vibrancy diminishes.
Reading may become difficult over time because of a reduced contrast between letters and their background.
Sensitivity to bright lights may make it difficult or impossible to drive at night because of glare from the headlights of oncoming cars. (People with diffuse cataracts in the rear walls of their lenses are particularly prone to glare sensitivity because bright light tends to scatter in their lenses.)
In very advanced cases, the pupil, which is normally black, looks milky or yellowish. The patient's vision is reduced to being able only to distinguish light from dark.

This photograph shows a cloudy white lens (cataract) over the pupil. Cataracts are a leading cause of decreased vision in older individuals, but children may have congenital cataracts. With new surgical techniques, the cataract can be removed, a new lens implanted, and the person can usually return home the same day.

Nuclear Cataracts. Cataracts of the lens nucleus are most commonly associated with aging. Symptoms include:

Hazy distance vision and increasing glare.
Progressive nearsightedness and the need for frequent changes in eyeglass prescriptions. This effect may even temporarily counteract age-related farsightedness and provide a temporary improvement in overall vision in some people. The improvement fades when the cataract advances sufficiently to overwhelm the inherent farsightedness. Eventually, as the cataracts grow worse, stronger glasses can no longer correct the patient's vision.

Click the icon to see an image of normal, near, and farsighted vision.

Cortical Cataracts. Cortical cataracts usually start on the outside of the cortex (the outer area of the lens).

They have very little initial effect on vision.
Glare can develop as these cataracts increase and approach the center of the lens.
Problems with distance vision, contrast sensitivity, and clarity may occur as the cataracts progress further.

Posterior Subcapsular Cataracts. Posterior subcapsular cataracts typically start near the center of the back part of the capsule surrounding the lens. These cataracts often advance rapidly. For many patients, major impairment of eyesight, including near-vision problems and glare, develops within several months.

Prognosis

Some cataracts stop progressing after a certain point. Cataracts are never reversible, however, even after eliminating factors, (such as drugs or illnesses), which might have promoted their development. If extensive and progressive cataracts are left untreated they can cause blindness. In fact, cataracts are the leading cause of blindness among adults age 55 and older. About 20.5 million Americans have at least one cataract. By 2020, that number is expected to jump to 30.1 million.

Fortunately, cataracts nearly always can be successfully removed with surgery. However, surgery is unavailable in certain parts of the world, leaving millions at risk for vision loss. Even in the U.S., where surgery has greatly reduced the risk of blindness, tens of thousands still lose their sight and millions more have poor vision because of cataracts. Cataracts also exact a financial burden. According to 2006 data, cataracts cost the U.S. nearly $7 billion each year in medical services and drug treatments.

In a 2001 study, cataracts were associated with a significantly higher mortality rate in older women, although not older men. These higher rates did not seem to be caused by certain health risks (for example, diabetes) that are often associated with both cataracts and lower survival rates. A 2004 study published by scientists in Italy appears to confirm the association between shortened lifespan and cataracts, especially cataracts confined to the lens nucleus and those that had already required surgery. A few other studies have also linked cataracts and vision impairment with poorer survival, regardless of accompanying health problems. One study reported that even middle-aged people with cataracts, particularly those in ethnic minority groups, had lower survival rates than their peers, perhaps because of premature aging.

Effect on Survival by Location of the Cataract. Some studies have suggested poorer survival specifically in patients with nuclear or mixed cataracts but not in those with cataracts in the cortex or capsule. Not all studies have found these differences. In any case, nuclear cataracts are highly associated with smoking and diabetes, although some studies have found lower survival rates in patients with nuclear cataract regardless of these health risks.

A 2002 study reported twice the rate of automobile accidents in patients who do not have cataract surgery compared to those who had surgery. This finding, however, is obscured by the possibility that patients who choose not to have surgery may have other health problems that put them at risk for accidents. Also, driving skills decline with age in nearly everyone. Cataract surgery, then, is no insurance against age-related accidents.

Reduced vision ranks third only behind arthritis and heart disease as a cause of impaired function in older people. Extensive cataracts can compromise the ability to earn a living, read, drive, or live independently. Although vision loss has been associated with a number of major adverse effects, few studies have reported on the effect of vision on daily activities.

Both blurred vision and problems in seeing contrasts contribute to impaired activity. The degree of these impairments, however, may have different effects on disability depending on individual tasks and needs. For example, even a slight loss in vision sharpness and contrast can impair the ability to recognize faces or slow down reading speed. For those who read very quickly, this may not be significant, but it could be very disabling for slower readers. In one study, people under age 65 rated blurred vision as reducing their quality of life more than any other chronic medical problem except shortness of breath.

Nevertheless some people who have small cataracts can see well enough around the clouded areas to live normally. But for many people, cataracts are extensive enough to interfere greatly with daily activities.

Risk Factors

Aging is the primary risk factor for cataracts, but other factors are also involved.

Nearly everyone who lives long enough will develop cataracts to some extent. A major study reported that:

About 40% of people age 55 - 64 years had some opaque areas in their lenses, and 5% had fully-developed cataracts.
About 70% of people age 65 - 74 years had opaque areas, and 18% had cataracts.
More than 90% of people age 75 - 84 years had opaque areas, and almost 50% had cataracts.

One study indicated that posterior subcapsular cataracts are the most common type in people under 70 years old, while nuclear and mixed cataracts are most common in people over age 80. The risk for nuclear cataracts also increases with age.

Women face a higher risk than men. Women who started menstruating late are at an even higher risk.

Eye Features. People who are nearsighted and those with brown eyes may be at higher than average risk. (Not all studies, however, report a higher risk in people with darker eyes.)

Obesity and Height. Studies are now reporting obesity as a risk factor for cataracts, notably posterior subcapsular cataracts, which form toward the back of the lens. A study of 17,150 people found a specifically higher rate of cataracts in overweight people who are tall and whose fat distribution is primarily in the abdomen.

A 9-year population study, published in 2004, revealed that African Americans have nearly twice the risk of developing cataracts than do Caucasians. Analysis of the 3,000 participants also demonstrated for the first time that the risk of cortical cataracts is 3 times higher in African Americans than Caucasians. Earlier studies also identified a higher cataract risk in the black population, suggesting that it may be due to other medical illnesses, particularly diabetes. It has long been known that African Americans are much more likely to become blind from cataracts and glaucoma than Caucasians, mostly due to lack of treatment.

Hispanic Americans are also at increased risk for cataracts. In fact, cataracts are the leading cause of visual impairment among Hispanics. A 2005 study found that cataracts were about 3 times more common in Hispanic patients age 65 - 84 years than in similarly aged white or African Americans. (The study evaluated Hispanic patients of Mexican descent.) As with African Americans, Hispanic patients often face barriers to access to care.

People with certain medical conditions, notably diabetes, are at high risk for cataracts, either because of a direct effect of the disease, its treatments, or both.

Autoimmune Diseases and Conditions Requiring Steroid Use. Medical conditions requiring high use of corticosteroids (commonly called steroids) pose a particularly high risk. Many of these medical conditions are autoimmune diseases, including rheumatoid arthritis, psoriasis, multiple sclerosis, systemic lupus erythematosus, Behcet's disease, and others.

Diabetes and People with High Blood Glucose Levels. People with diabetes type 1 or 2 are at very high risk for cataracts and are much more likely to develop them at a younger age. They also have a higher risk for nuclear cataracts than nondiabetics. Cataract development is significantly related to high levels of blood sugar (called glycemia), and cataracts in people with diabetes are sometimes referred to as so-called sugar cataracts. Even people without diabetes but with higher-than-normal blood sugar levels are at high risk for cataracts. Some doctors now recommend that children with diabetes undergo an eye exam to check for cataracts at the time they are diagnosed.

Insulin is a hormone produced by the pancreas that is necessary for cells to be able to use blood sugar.

Exposure to even low-level UVB radiation from sunlight increases the risk for cataracts. A 2003 study published provided new evidence supporting the link between sun exposure and nuclear cataracts. The risk was highest among those who had significant sun exposure at a young age. Additional studies suggesting risk associated with sunlight exposure report:

The closer people live to the equator the greater the chance for cataracts. As suggested by a study in Southern France, sunlight exposure in these climates also increases the risk for severe cortical or mixed cataracts. In this study, even wearing sunglasses did not reduce the risk for these cataracts, although it did for posterior subcapsular cataracts.
People whose jobs expose them to sunlight for prolonged periods are at higher risk. People in southern climates whose occupations, such as fishing or oyster farming, exposed them to very intense sunlight were at high risk for all cataracts, including posterior subcapsular cataracts. (People in more northern climates with similar occupations may not have as high a risk.)
Occupational exposure to very intense artificial light, such as arc welding, increases the risk for cataracts.

Smokers. A study of nearly 18,000 doctors showed that those who smoked 20 or more cigarettes a day had approximately twice the risk of developing cataracts. Smokers are at particular risk for cataracts located in the nuclear portion of the lens, which limit vision more severely than cataracts in other sites. Quitting smoking may reverse some of this damage.

Alcohol Users. Chronic drinkers are at high risk for a number of eye disorders, including cataracts. Alcohol has been implicated in cataract development in a number of studies. Wine provided the least risk, and the more moderate the drinking the lower the risk. Alcohol may work directly on the proteins in the lens itself and indirectly by affecting absorption of nutrients important to the lens.

Long-term environmental lead exposure may increase the risk of developing cataracts according to a study published in the Journal of the American Medical Association. Researchers assessed bone lead levels in 795 men aged 60 years and older. Because lead tends to accumulate over time in the skeleton, the researchers measured lead levels in the men’s shin bones. Men with the highest levels of lead were three times more likely to have cataracts than men with the least amount of lead.

A poor diet may deprive the body of amino acids and B vitamins that are essential for eye health. A French study of elderly adults found that lower blood levels of the protein albumin were associated with an increased risk of cataracts.

Other conditions that can trigger the process leading to cataracts include:

Physical injury to the eye (such as a hard blow, cut, or puncture)
Chemical burns
Electrical shock injuries
Chronic exposure to intense heat or cold

Prevention

Although cataracts are not completely preventable, their occurrence can be delayed. Quitting smoking, avoiding overexposure to sunlight, drinking alcohol in moderation, and eating plenty of fresh fruits and vegetables can delay the formation of cataracts. No evidence exists that using eye drops or ointments or performing eye exercises will stem the onset of cataracts.

The simplest and most effective way to protect against ultraviolet (UV) radiation is to stay out of the sun. A hat and cover-up should be worn outside, particularly when the sun is most intense (10 AM - 3 PM). A wide-brimmed hat can reduce eye exposure to UVB radiation by 30 - 50%. Because the sun's rays are highly reflective, sitting in the shade or under an umbrella by itself does not guarantee protection.

Clothing that blocks or screens the harmful rays of the sun (UVA and UVB), in combination with wide-brimmed hats, sunglasses, and sunscreen, all help prevent damage to the eyes and skin. Any one of these by itself, even the sunscreen, may not be enough to prevent sun damage.

Note: Avoidance of the sun should not be taken to extremes. Some sunshine is desirable. Moderate sun exposure provides an important source of vitamin D, which is essential for healthy bones. There is a link between lack of sun exposure and depression (known as seasonal affective disorder, or SAD).

Click the icon to see an image of vitamin D.

Sunglasses. Protective sunglasses do not have to be expensive. Sunglasses are classified into three categories based on UVA and UVB protection:

Cosmetic purpose sunglasses block at least 70% UVB and up to 60% UVA. People should avoid these glasses if they have any risk for cataracts or eye problems.
General purpose sunglasses block at least 95% UVB and a minimum of 60% UVA. At the very least, people should purchase general purpose sunglasses that are labeled "Meets ANSI Z80.3 General Purpose UV Requirements." Labels should indicate that sunglasses block UV radiation up to 400 nm.
Special purpose sunglasses block at least 99% UVB and a minimum of 60% UVA rays. These are the optimal sunglasses for people at risk for cataracts. Ideally they should have the Skin Cancer Foundation's Seal of Recommendation for Sunglasses. Special purpose glasses should wrap around the head and block light coming from above, below, and both sides of the glasses. They should also fit snugly on the nose.
Lenses that are simply dark but not coated with UV-absorbing material may actually increase the risk of cataracts because the pupil widens to compensate for the shaded glass. This may allow more harmful ultraviolet waves to enter. Polarized glasses cut glare but have no effect on UV radiation. Mirror finishes without additional processing for UV blockage are also not fully protective. There is some controversy over whether blue light is harmful to the eyes. Some people prefer amber lenses, which block out the blue spectrum.

Antioxidant vitamins C and E. Because of the role oxidants may play in cataract formation, researchers are investigating the benefits of antioxidant vitamins and other food chemicals. Vitamins C, E, and riboflavin (a B vitamin), for example, are helpful in preserving levels of glutathione, an enzyme that helps protect against oxidation in the eye. Low levels of vitamin C in the lens of the eye have been particularly strong predictors of cataracts. Some evidence also suggests that ultraviolet B radiation interacts with deficiencies in certain antioxidants, such as vitamin E and zinc, to increase damage in the corneas and lenses of the eye.

Evidence on the benefits of supplements of vitamin E or C, or vitamin-rich foods, is conflicting. For example, in two identically constructed trials in the US and Britain, the American group derived apparent benefits from vitamins E, C, and beta carotene while the British group reported very little cataract protection. A 2005 study suggested that long-term use of vitamin E supplements may slow cataract development. However, in a major on-going American study called the Age-Related Eye Disease Study (AREDS), researchers reported no difference in the incidence of cataracts after 7 years in people who took the antioxidant vitamins compared to those who took sham vitamins.

High doses of vitamins may have harmful effects. It is always wise, in any case, to pursue a healthy diet that is low in fats, high in complex carbohydrates, and rich in fruits and vegetables.

B vitamins. Some studies report some protection from a number of B vitamins, including vitamins B1 (thiamin) B2 (riboflavin), B3 (niacin) and B12 (folate). Riboflavin, for example, plays a critical role in the production of glutathione, an enzyme that helps protect against oxidation in the eye. All forms of vitamin B are widely available in dairy products, fortified grains, and meat.

Carotenoids. Carotenoids are a group of more than 700 fat soluble nutrients that produce the colors in foods such as carrots, pumpkins, sweet potatoes, tomatoes, and other deep green, yellow, orange, and red fruits and vegetables. Many are proving to be very important for health. Different carotenoids may be more beneficial then others. They include:

Xanthophylls are compounds that form a particular category of carotenoids. The xanthophylls lutein and zeaxanthin are found in the lenses of the eye and may be of significant importance for people at risk for cataracts. Some evidence indicates supplements of xanthophyll-rich foods may help retard the aging process in the eye and protect against cataracts. In fact, some experts suggest that the higher risk of cataracts in women compared to men may be partly due to a lesser ability to transport these carotenoids from the blood into the eye. Xanthophylls can be obtained from dark green leafy vegetables (such as spinach), broccoli, and eggs.
Lycopene is an important carotenoid that may also play an important role in eye health as a person ages. Tomatoes are the importance sources of lycopene.
Beta carotene is the most widely studied carotenoid and is a powerful antioxidant. It has been specifically studied for cataract protection. Most studies, however, have found little or no benefits. A 2003 study did suggest that beta carotene may protect against cataracts in smokers, although it is important to note that other studies report a higher risk for lung cancer in smokers who take beta carotene.

Click the icon to see an image of folate sources.

Click the icon to see an image of vitamin B12 sources.

Click the icon to see an image of riboflavin sources.

Phytochemicals. Phytochemicals are substances in plants that have beneficial effects. Dark colored (green, red, purple, and yellow) fruits and vegetables usually have high levels of important plant chemicals and have been associated with a lower risk for cataracts. Tea contains certain plant chemicals called polyphenols that have been associated with protection against cataracts.

Click the icon to see an image of phytochemicals.

Diagnosis

Either an ophthalmologist or an optometrist can examine patients for cataracts, but only ophthalmologists are qualified to treat cataracts.

An ophthalmologist is a doctor who specializes in the medical and surgical care of the eye.
An optometrist is engaged in the practice of eye care, but is not a doctor and cannot prescribe medication or perform surgery.

The eye professional can observe cloudy areas on the lenses with a direct physical examination, even before the cataracts begin to interfere with vision. Cameras can measure the cataract density. Various vision tests are also performed.

Snellen Eye Chart. To determine how clearly a person can actually see, the Snellen eye chart is used, with rows of letters decreasing in size:

From a specified distance, usually 20 feet, a person reads the letters using one eye at a time.
If a person can read down to the small letters on the line marked 20 feet, then vision is 20/20 (normal vision).
If a person can read only down through the line marked 40 feet, vision is 20/40; that is, from 20 feet the patient can read what someone with normal vision can read from 40 feet.
If the large letters on the line marked 200 feet cannot be read with the better eye, even with glasses, the patient is considered legally blind.

The visual acuity test can be performed in many different ways. It is a quick way to detect vision problems and is frequently used in schools or for mass screening. Driver license bureaus often use a small device that can test the eyes individually and then together.

Other Tests. A number of other tests are used to diagnose cataracts or to determine if surgery is needed.

A chart similar to the Snellen chart, which has the same size letters, but in different contrasts with background, is used to test contrast sensitivity,
Glare sensitivity is tested by having the patient read a chart twice, with and without bright lights.
Tests of macular function, which evaluate the eye's acute vision center, can help the ophthalmologist determine the expected improvement from surgery.
The corneal endothelium, a layer of cells lining the cornea, is sensitive to surgical trauma and should be evaluated before any intraocular operation.
Patients with other eye disorders may require a number of other pre-operative tests.

Although eye tests aid in making a diagnosis for cataracts, results do not always reflect the quality of life and how effectively people function at home:

Some people with cataracts perform poorly on the tests yet appear to have no difficulty functioning normally day-to-day.
Others perform well on the tests but insist that their eyesight is bad enough to curtail ordinary activities, such as driving.

Standard eye tests, therefore, may not be useful for determining whether a patient actually needs cataract surgery.

In general, even if cataracts are diagnosed, the decision to remove them should be based on the patient's own perception of vision difficulties and needs and the effect of vision loss on normal activity. The patient should also be aware of all the risks and costs of surgery. In order to determine the quality of life, the patient may be given a questionnaire such as National Eye Institute Visual Function Questionnaire, which asks 39 questions related to vision and daily activities. This test or others may be useful for determining if eye disease is actually impairing the ability to function.

Treatment

Although surgery is the only remedy for cataracts, it is almost never an emergency. Most cataracts cause no problem other than reducing a person's ability to see, so there is no harm in delaying surgery.

Early cataracts may be managed with the following measures:

Stronger eyeglasses or contact lenses
Use of a magnifying glass during reading
Strong lighting
Medication that dilates the pupil. (May help some people with capsular cataracts, although glare might be a problem with this treatment.)

It is important to note, however, that no treatments will prevent cataract formation or progression or make a cataract disappear.

Progression of Cataracts. Patients and their families usually have plenty of time to consider options carefully and discuss them with an ophthalmologist. There is no constant rate at which cataracts progress:

Some develop to a certain point and then stop.
Even if a cataract does progress, it may be years before it interferes with vision.
Only in a very few, very rare circumstances is it necessary that cataract surgery be performed immediately.

Each year about 2.8 million cataract operations are performed, making it the most common operation in the U.S. for people over age 65. Cataract surgery may be the oldest procedure in the world, having been introduced to Europe from India by Alexander the Great's army.

In the past, cataract surgery was not performed until the cataract had become well developed. Newer techniques, however, have made it safer and even more efficient to operate in earlier stages. In fact, modern cataract techniques not only remove cataracts but are also becoming important procedures for correcting astigmatism. Cataract surgery improves vision in up to 95% of cases and prevents millions of Americans from going blind.

Nevertheless, considerable evidence suggests that, because of the ease and relative safety of the procedure, it may be performed more often than needed. Patients having operations now tend to have better preoperative vision than those operated on 10 or 20 years ago. In a study of 800 cataract operations, 25% of the patients said that clouding had had no obvious effect on their lives before the procedure.

Cataract surgery is very successful. It has the following advantages:

Nearly all patients enjoy better vision after surgery. Advanced procedures in lens development are allowing correction of astigmatism as well as cataract removal. (Patients with significant eye disease, such as glaucoma or corneal or retinal disease, may not experience the same degree of improvement.)
Many people experience significant improvement in quality of life after the operation.
Some studies indicate that better vision might even help slow down age-related health problems unrelated to the eyes.

In general, surgery is indicated for people with cataracts under the following circumstances:

The Snellen eye test reports 20/40 or worse, with the cataract being responsible for vision loss and glasses or visual aids no longer being helpful.
Everyday activities have become difficult to perform to the point that independence is threatened. Questionnaires that assess the effects of cataracts on quality of life have been developed.
The patient is at risk for falling in low light.

These guidelines are general, however. Whether surgery is appropriate or not further depends on the cataract patient's specific condition and needs. Some examples include the following:

Even if the criteria for surgery are met, a very sick, very elderly person in a nursing home may have less need for sharp vision than an active younger adult. Among very elderly patients (85 years and older), especially those with serious health problems, there are also higher risks for complications during surgery and poor outcomes afterward. Nevertheless, these cautions should not prevent the very elderly from having this procedure; vision improvement rates are still over 85%.
Even if the criteria for surgery are not met, some people with eye tests of 20/40 or better might want surgery because of problems with glare, double vision, or the need to have an unrestricted driver's license.
Even if the criteria for surgery are not met, if retinal disease is also suspected (usually a complication of diabetes), the doctor may perform cataract surgery in order to have a clear view of the eye.

Because of the risks, albeit small ones, of poorer vision or blindness, no one should be forced to have cataract surgery if they don't want it or are not strong enough to undergo the procedure. If there are any doubts about whether or not to undergo cataract surgery, a second opinion should be considered.

The patient should ask the ophthalmologist the following questions before agreeing to cataract surgery:

Is my cataract surgery an emergency?
Are the cataracts the only cause of my poor vision?
How much experience do you have with this procedure?
Do I have other eye diseases that might complicate surgery or reduce my benefit?
Do I have other health problems that might further complicate eye surgery?
Will you be able to implant an intraocular lens?
What type of procedure will you use?
Will I have to stay in the hospital overnight?
Afterwards, what are my chances of having poorer vision or becoming totally blind in that eye?
How well should I ultimately be able to see out of the operated eye?
How long will it take to heal?
How long will it take to achieve my best eyesight?
Will I have to wear glasses or contact lenses after surgery?
When will I get my final eyeglass prescription?
How soon after surgery will I be able to see well enough to go back to work? Drive a car? Return to full activity?
What will the surgery cost?

Cataract surgery is now usually done as an outpatient procedure under local anesthesia and takes less than an hour. Preoperative preparations may include:

Having a general physical examination is important for patients with medical problems such as diabetes. Diabetes can cause damage to the blood vessels of the eye’s retina, a condition called diabetic retinopathy. Recent research suggests that patients who have diabetic retinopathy and poor blood sugar control should not have their blood sugar rapidly corrected before cataract surgery. Correcting blood sugar too quickly before surgery can cause vision problems after surgery.
The ophthalmologist will use a painless ultrasound test to measure the length of the eye and determine the type of replacement lens that will be needed after the operation.
Topical application of so-called fluoroquinolone antibiotics (such as ofloxacin or ciprofloxacin) may be applied preoperatively to protect against postoperative infection.
Most healthy patients are given either a local injection or topical anesthetic. The patients who report the least pain during the operation are those given a sedative followed by a local injection rather than just the topical drug.
Some patients may require a general anesthetic, such as those who are very anxious, those who are unable to cooperate with the surgeon, and those who are allergic to local anesthetics.

All cataract procedures involve removal of the cataract-affected lens and replacing it with an artificial lens.

Phacoemulsification. Phacoemulsification (phaco means lens, emulsification means to liquefy) is now the most common cataract procedure in the United States and accounts for 85% of cases. Benefits are greater than with standard extracapsular surgery, and it may be particularly helpful for people with diabetes.

The procedure generally involves:

The surgeon makes an incision, which is much smaller than with standard cataract extraction.
Ultrasound is then used to break up the clouded lens into small fragments.
The tiny pieces are sucked out with a vacuum-like device.
A replacement lens is then usually inserted into the capsular bag where the natural lens used to be. In most cases, this is an intraocular lens (IOL), which is foldable and slips in through the tiny incision.
Because the incision is so small, it is often watertight and does not require a suture afterward, particularly if a foldable lens has been used. A suture may be needed if a tear or break occurs during the procedure or the surgeon inserts a rigid lens that requires a wider incision.

Click the icon to see an illustrated series detailing cataract surgery.

Phacoemulsification requires only local anesthesia. Newer methods for administering local anesthesia produce few complications. Most phacoemulsification procedures now take about 15 minutes, and the patient is usually out of the operating room in about an hour. There is little discomfort afterward and visual rehabilitation takes about 1 - 3 weeks.

Phacoemulsification is sometimes combined with viscocanalostomy, a glaucoma surgical procedure, for patients who have both glaucoma and cataracts. Recent research suggests that phacoviscocanalostomy (as this combined procedure is called) is safe and effective for this group of patients.

Surgeons in the U.S. and Europe are currently investigating Microphaco, a new approach to cataract surgery that uses two smaller (micro) incisions. The smaller incisions measure about 1.6 mm compared to the traditional 3 mm. Experts say this procedure is expected to revolutionize refractive and cataract surgery.

Other Lens Removal Techniques. The AquaLase device uses pulses of fluid to wash away the clouded lens. Some experts believe this approach causes less trauma to the eye, and allows for a quicker recovery time for the patient, than the ultrasound used in phacoemulsification.

Extracapsular or Intracapsular Cataract Extraction. Extracapsular cataract extraction was the original standard procedure, but is now generally used only in patients who have an extremely hard lens. It typically involves the following steps:

The ophthalmologist works under an operating microscope to make a small incision in the cornea of the eye.
The surgeon then extracts the clouded lens through this incision.
The capsule is left in place, which adds structural strength to the eye and enhances the healing process. (Less commonly, in intracapsular cataract extraction, the surgeon removes the lens and the entire capsule. There are greater risks with this procedure for swelling and retinal detachment.)
A replacement lens is then usually inserted.
A small suture is needed to stitch the incision together.

It takes about 2 - 4 weeks to completely restore vision.

With the clouded lens removed, the eye cannot focus a sharp image on the retina. A replacement lens or eyeglass are therefore needed:

Intraocular Lenses (IOL). In about 90% of cataract operations, an artificial lens, known as an intraocular lens (IOLs), is inserted. Until recently, IOLs used a pair of little spring-loaded loops to hold the lens in place. Most IOLs are now foldable, which makes insertion easier. In fact, a prefolded lens is now available that unrolls to fit the eye as body temperature warms it.

IOLs are available as monofocal or multifocal. Monofocal lenses correct only one type of vision range (such as distance vision). Multifocal lenses are designed for patients who need correction for a range of vision. A 2006 study suggested that the Tecnis IOL works particularly well for patients who require a multifocal IOL.

Although all the lens materials are presumably chemically inert, there are some reports of specific problems, notably a risk for causing a reaction that leads to the development of secondary cataracts, a condition called posterior capsular opacification. IOLs include the following materials:

Acrylic: The majority of IOLs are made from acrylic, which allows a controlled unfolding of the lens. Evidence indicates that this material provides a better visual outcome and fewer complications than other standard IOLs.
Polymethylmethacrylate (PMMA): Has the longest safety record. A PMMA IOL coated with heparin, a blood thinner drug, helps protect against the development of a secondary cataract after surgery.
Silicone: Can be inserted through a smaller incision than other materials. It has the highest rates of secondary cataracts. Newer forms of silicon IOLs may pose a lower risk.

Other materials are under investigation.

IOL brands include:

Crystalens: The FDA approved the Crystalens IOL in 2003. It is made from a form of silicone called Biosil. The Crystalens uses "hinges" that allow the lens to move, mimicking the eye's natural ability to focus automatically and seamlessly at all distances. Studies indicate that when used along with standard cataract removal methods, the Crystalens can restore a full range of functional vision, from distance to reading vision, without total dependence on glasses or contact lenses.
Array: The Array lens also uses silicon. It is one of a number of so-called second-generation IOLs that is available as a multifocal lens to help correct presbyopia (nearsightedness).
Tecnis: The Tecnis foldable IOL was specifically designed to improve functional vision of cataract surgery patients. Tecnis has a patented surface that reduces light scattering (spherical aberration) of the cornea, which can negatively affect vision. In April 2004, The FDA approved new labeling claims for Tecnis, stating the lens may help improve driving safety for senior cataract patients. In clinical trials, simulated night driving and visual acuity (20/20, 20/40) results were significantly better in eyes implanted with the Tecnis IOL. In addition, spherical aberrations were significantly less when compared to the traditional lens with the spherical optic.
AcrySof Natural: Approved in 2003, the yellow-tinted Acrysof Natural IOL was the first foldable lens to filter ultraviolet and blue-light. Eliminating both UV and portions of the high-energy blue light help prevent retinal damage. This lens also conforms to the natural shape of the human lens capsule so it remains centered over the eye.
AcrySof ReSTOR: The AcrySof ReSTOR IOL is approved in the U.S. for patients with and without presbyopia. The lens enhances vision at near, intermediate, and distant ranges. In clinical trials, 80% of patients who received the lens did not require glasses after cataract surgery. The FDA approved the AcrySof ReSTOR in March 2005.

IOLs are designed to improve specific aspects of vision. The choices include:

Lenses that address a single fixed focal point. Such lenses are suitable either for reading or for distance vision, but not both. If a distance lens is implanted, the surgeon prescribes glasses or contact lenses for reading. If a reading lens is implanted, lenses for seeing distances will be prescribed.
Lenses that address multifocal points. Multifocal lenses can focus at different points for both reading and distance vision. One study reported that more than 80% of patients with multifocal lenses were able to see 20/40 or better without correction. However, contrast may be reduced and some patients experience glare and halos, particularly at night.
Lenses are available that will correct astigmatism after cataract surgery.

The patients and the doctor must make these decisions based on specific visual needs.

Contact Lenses or Cataract Glasses. A few patients do not receive a new lens and rely solely on corrective eyeglasses or contact lenses. Such patients may include:

Patients who are extremely near-sighted
Patients with other eye disorders

In such cases, the patient typically returns to the ophthalmologist for a check up the day after surgery, and three additional check-ups are scheduled over a 2-month period. The ophthalmologist can usually give a final prescription for eyeglasses or contact lenses about three months after surgery.

Choosing Contact Lenses. Contact lenses allow clear vision but do not magnify, so those who choose contact lenses after surgery may have to wear reading glasses. Contacts can be prescribed either for use only during the day or for extended-wear. Occasionally contact lenses cause problems, such as infection. Those who wear them should call their eye doctor if they have red or watery eyes, pain, or sensitivity to light.
Cataract Glasses. Until the advent of contact lenses, people who had cataract surgery had no choice but to wear glasses with thick lenses, sometimes called Coke-bottle glasses. These glasses have gotten thinner and lighter in recent years, but they may still be cumbersome. Cataract glasses are different from ordinary glasses and are sometimes difficult to adjust to. Images can seem distorted and may appear suddenly within the peripheral vision. Distances may be hard to judge.

Sometimes a patient has two cataracts and needs to wear glasses between the first and second operation. They are particularly troublesome during this period. The treated eye will see images magnified while the other eye will view them as they actually are, and the brain cannot blend the two images. This is a temporary state that is resolved by the second operation.

Modern cataract surgery is one of the safest of all surgical procedures. Most complications, even if they occur, are not serious. They can include the following:

Swelling and inflammation. Risk is about 1%. This complication is particularly harmful for patients with existing uveitis (chronic inflammation in the eye, which can be due to various conditions).
Glare. Patients may experience glare after surgery from light scattering at the edges of the new lens, particularly with square-edged IOLs, which are typically used with posterior capsular cataracts. In most cases, this is a temporary problem that resolves after a few weeks. Sometimes, the problem persists, and the patient requires another operation. Some research suggests that glare can be significantly reduced by texturizing the edges of the square lens.
Materials used in some lenses trigger an immune response in about half of patients. This causes inflammation and tiny deposits of tissue in the eye that lead to secondary cataracts -- called posterior capsule opacification. Studies suggest that silicone implants pose the highest rates for inflammation and secondary cataracts, particularly in patients with other eye diseases. Newer silicon IOLs pose less risk. In one study, the lowest rates were with IOLs made of acrylic and heparin-coated PMMA.
Retinal detachment. In rare cases, the retina at the rear of the eye can become detached. Risk is very low (0.1%), and phacoemulsification poses less of a risk for this than standard surgery.
Atonia (loss of muscle tone that results in a disturbing glare). (Phacoemulsification poses less of a risk than standard surgery.)
Glaucoma. This is an eye condition in which the pressure of fluids inside the eye rises dangerously. Risk is very low, but patients should be sure to avoid activities after surgery that increase pressure.

Infection. This is very rare (0.2%), but is devastating if it does develop.
Blisters on the cornea. There is a higher risk of rupture with phacoemulsification, but the risk is extremely low, particularly for experienced eye surgeons. In 2004, the FDA approved the StabilEyes Capsular Tension Ring (CTR) to help support the eye's capsular bag during cataract surgery, especially in those with weak or broken eye fibers (zonules). A CTR is an open ring made of polymethylmethacrylate (PMMA). The ring goes into the capsular bag itself, stabilizing the eye.
Bleeding can develop inside the eye. Risk is about 1% for minor bleeding and 1 in 10,000 for severe bleeding.
An implanted IOL can become damaged or dislocated. Risk is very low.
The surgery itself can produce vision loss or impairment. The risk for this is 1 in 1,000. (Phacoemulsification poses less of a risk than standard surgery.)
Macular degeneration. Macular degeneration, in which the retina breaks down, is a common cause of vision loss in the elderly. In a 5-year study, people who underwent cataract surgery had twice the risk for progression of age-related macular degeneration. Interestingly, another study reported that cataract surgery significantly helped patients who had existing macular degeneration. More research is needed to refute or confirm this finding.

Click the icon to see an image of macular degeneration.

Phacoemulsification does have some specific complications, although they are rare, particularly with experienced eye surgeons. They include:

Rupture of the lens capsule.
Loss of the lens nucleus into the eye fluid. (This will require removal by a specialist and may result in poorer vision.)
Flying fragments of the lens can damage the cornea or threaten the retina.
Pre- and postoperative changes in blood pressure, which are generally not a problem, should be observed carefully, since in some cases the changes may be extreme.

In about 30% of cases patients develop secondary cataracts within 1 - 5 years after either procedure, which require different treatment choices.

Preventing Infection and Reducing Swelling. The ophthalmologist may prescribe the following medications:

A topical antibiotic (neomycin or, more effectively, gentamicin). This drug protects against infection.
Corticosteroid eyedrops or ointments are often used to reduce swelling. Corticosteroids (commonly called steroids) are potent anti-inflammatory drugs. However, they also pose a risk for pressure in the eye and infection. One study reported less visual sharpness with the use of steroids compared to antibiotics. Some newer steroids such as rimexolone, loteprednol, and fluorometholone may pose a lower risk for abnormal pressure.
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as diclofenac, ketorolac, naproxen, and voltaren, also reduce swelling and do not pose the same risks as steroids. Newer NSAIDS that have been approved to treat pain and swelling after cataract surgery include bromfenac (Xibrom) and nepafenac (Nevanac).

In one study, applying an ice pack for 2 hours immediately after phacoemulsification improved comfort level and reduced inflammation, even days after the operation. This simple procedure has no adverse effects and patients should discuss it with their surgeons before the operation.

Factors That Increase Risk for Complications. The risks of complications are greater for the following people:

Patients who have other eye diseases.
People with diabetes. Intracapsular and extracapsular cataract extraction are known to pose a high risk for the development or worsening of retinopathy, a known eye complication of diabetes. Experts have hoped that phacoemulsification would pose a lower risk, but a 2001 study reported a high percentage of retinopathy progression after this procedure. The amount of experience a surgeon has plays a role in whether or not a patient has this complication.
People who have taken tamsulosin (Flomax) or other alpha-1 blocker drugs. Tamsulosin is a muscle relaxant prescribed for treatment of several urinary conditions including benign prostatic hyperplasia (BPH). In 2005, a leading ophthalmologic association and the FDA warned that tamsulosin may cause intraoperative floppy iris syndrome (IFIS), a loss of muscle tone in the iris that can cause complications during eye surgery. Problems have been reported both for patients who were taking the drug during surgery as well as those who had stopped taking the drug weeks or months before surgery. Men who have taken tamsulosin or similar drugs should inform their eye surgeon. The surgeon may need to use different techniques to minimize the risk of IFIS. A 2006 study indicated that patients can have safe and successful surgeries with these modified techniques.

Returning Home and Follow-up Visits.

Patients usually leave the surgical site within an hour of surgery. Cataract surgery almost never requires an overnight hospital stay.
They need to have someone drive them home and stay with them for a few days until their vision is acclimated.
The patient is usually examined the day after surgery and then during the following month. Additional visits are made as required.
Vision usually remains blurred for a while but gradually clears, usually over a 2 - 6 week period. (It can take longer.)
When the doctor decides the condition has stabilized, the patient will receive a final prescription for glasses or contacts.

Protecting the Eye. Postoperative protection of the eye typically involves:

The ophthalmologist usually tapes a bandage over the eye to protect it during the healing process.
When changing the bandage, the eye can be cleaned gently using a washcloth dipped in warm water without soap. A new bandage can then be positioned and taped.
It is very important not to press or rub the eye during this procedure.
An eye shield may be placed over the bandage at night.

Avoiding Glaucoma. Cataract surgery can cause glaucoma, a condition in which the pressure of fluids inside the eye rises dangerously. It is very important to minimize any activity that increases internal eye pressure. Postoperative cataract patients take the following precautions:

Minimize vigorous exercise.
Put on shoes while sitting and without lifting up the feet.
Kneel instead of bending over to pick something up.
Avoid lifting.
Limit reading since it requires eye movement (watching television is all right).
Sleep on the back or on the unoperated side.

Cataracts and Glaucoma. For patients with both glaucoma and cataracts, experts recommend:

In patients with cataracts and poorly controlled glaucoma, a two-step procedure for both eye conditions is needed. The patient first receives a trabeculectomy for glaucoma, followed by cataract surgery. Fluid leakage and the presence of blood in the back chamber of the eye are potential complications of this combined procedure. Phacoemulsification has improved success rates and reduced high complication rates of the double procedure compared with extracapsular cataract extraction. New advances that replace trabeculectomy with nonpenetrating glaucoma surgery may prove to be beneficial.
In patients who have cataracts plus either closed-angle glaucoma or open angle glaucoma that is stabilized with medication, the cataract may be able to be extracted and medication continued for the glaucoma.
A major 2002 analysis suggested that the combined approach generally offers better control over eye pressure for patients with both cataracts and glaucoma. The best surgical procedure, however, is still uncertain.

Cataracts and Corneal Disease. Patients who have both cataracts and corneal disease may undergo one of the following:

Combination Procedure. A single operation that combines three procedures. The combined procedure has been used since the late 1970s and employs extracapsular cataract extraction and intraocular lens insertion with corneal transplantation (called penetrating keratoplasty).
Sequential Procedure. An operation that uses two procedures sequentially. The sequential option performs the cataract procedures and the corneal transplantation separately.

Recovery of vision is usually much more rapid after the combined procedure than after the sequential procedures. Performing the procedures sequentially may also carry a higher rejection rate of the implant, although a 2003 study found no differences in failure rates between the two approaches after a year.

In any case, many experts recommend that for most patients the sequential procedures may be the better option because it appears to have fewer of the following complications than with the combined procedure:

Posterior capsule rupture
Eye fluid loss
Postoperative refractive errors, which result in abnormal distribution of light patterns

The rate of these errors still depends on the skill of the surgeon and the power of the implanted lens no matter what approach is used.

About 30% of patients who undergo extracapsular cataract surgery develop a secondary "after-cataract" called posterior capsular opacification. Posterior capsular opacification generally occurs because of the following events:

After surgery, there are still some natural lens cells left behind that proliferate on the back of the capsule.
The capsule gradually becomes cloudy and interferes with clear vision the same way the original cataract did.

According to a 2001 study, the probability of developing a secondary cataract was 6% at 1 year, 15% at 2 years, 23% at 3 years, and 38% at 9 years. The risk is lower with phacoemulsification. Secondary cataracts are more likely to occur in younger patients, in those with diabetes, or when cataract surgery is combined with vitrectomy (clearance of debris from the fluid in the eye).

Preventing Posterior Capsular Opacification. Studies suggest that acrylic lenses pose the lowest risk for posterior capsular opacification. A number of substances to prevent posterior capsular opacification are under investigation, including tranilast eyedrops, new lens materials, special capsular rings inserted during phacoemulsification, and new coatings on the implanted lens.

Treatment Decisions for Cataracts in the Second Eye. If a person has a cataract in a second eye, the issues for decision making are the same as for the first eye. The time of the procedure in the case of two cataracts is unclear. Doctors have long recommended that surgery on the second eye should be postponed until the first eye has healed and the results known (about a year).

One study has called this recommendation into question. It was conducted in England, where for budgetary reasons, there are long waits for second-eye cataract surgeries. In the study, patients who waited 7 - 12 months for the second-eye surgery reported significant difficulty in reading and performing ordinary tasks during the waiting period. Only 1% of patients who had the second surgery within 6 weeks reported having trouble seeing. In addition, 70% of those who waited experienced problems in depth perception, which can cause difficulty in walking and driving; only 12% who didn't wait reported this problem. Patients with double cataracts should discuss all options with their surgeon.

Treatment for Posterior Capsular Opacification. The standard treatment is laser surgery known as a YAG capsulotomy. (Capsulotomy means cutting into the capsule, and YAG is an abbreviation of yttrium aluminum garnet, the laser most often used for this procedure.)

This is an outpatient procedure and involves no incision.
Using the laser beam, the ophthalmologist makes an opening in the clouded capsule to let light through.
After the procedure the patient should remain in the doctor's office for an hour to be sure that pressure in the eye is not elevated.
An eye examination for any complications should follow within 2 weeks.

Complications. Laser surgery has become so commonplace that some ophthalmologists use it after cataract surgery to prevent later clouding. However, laser surgery carries its own risks and possible complications, similar to those of cataract surgery itself, and can also lead to poorer vision or blindness. About 1% of laser surgery patients develop a detached retina, which is much higher than the risk from the original cataract surgery.

Click the icon to see an image of a detached retina.

In some people, particularly those with glaucoma or who are severely nearsighted, the pressure in the eye may spike after laser surgery. Certain drugs used for treating glaucoma, such as dorzolamide (Trusopt) or apraclonidine (Iopidine), may helpful for preventing this occurrence. It is strongly recommended, however, that this surgery not be performed to prevent a secondary cataract, but only if the lens capsule clouds up again.

Infants. Treatment of infants first depends on whether one or both eyes are affected:

For infants born with cataracts in one eye, the American Academy of Ophthalmology recommends surgery as soon as possible, by 4 months or ideally even earlier. The procedure is followed by contact lens correction and patching of the unaffected eye. Although this approach is successful in many cases, some children still become blind in the affected eye. There is also a high risk for glaucoma after surgery.
In infants with cataracts in both eyes, surgery is not always an option. In some cases, it may be performed sequentially, with the second eye operated on a few days after the first. Phacoemulsification appears to pose a much higher risk for secondary cataracts than standard lens removal.

Toddlers and Older Children. Intraocular lens replacement is now becoming standard treatment for children 2 years and older.

Resources

www.ascrs.org -- The American Society of Cataract and Refractive Surgery
www.aao.org -- American Academy of Ophthalmology
www.nei.nih.gov -- National Eye Institute
www.eyesurgeryeducation.com -- Eye Surgery Education Council
www.lighthouse.org -- Lighthouse International
www.aao.org/aao/find_eyemd.cfm -- Find an ophthalmologist

References

Eke T, Thompson JR. Serious complications of local anaesthesia for cataract surgery: a one-year national survey in the United Kingdom. Br J Ophthalmol. 2006 Nov 23; [Epub ahead of print]

Hutz WW, Eckhardt HB, Rohrig B, Grolmus R. Reading ability with 3 multifocal intraocular lens models. J Cataract Refract Surg. 2006 Dec;32(12):2015-21.

Klein BE, Klein R, Lee KE, Grady LM. Statin use and incident nuclear cataract. JAMA. 2006 Jun 21;295(23):2752-8.

Rein DB, Zhang P, Wirth KE, Lee PP, Hoerger TJ, McCall N, et al. The economic burden of major adult visual disorders in the United States. Arch Ophthalmol. 2006 Dec;124(12):1754-60.

Wishart MS, Dagres E. Seven-year follow-up of combined cataract extraction and viscocanalostomy. J Cataract Refract Surg. 2006 Dec;32(12):2043-9.

Review Date:
3/1/2007
Reviewed By:
Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

A.D.A.M. Copyright

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