Experts Say Have Regular Eye Exams As You Age

June Is Vision Research Month

Even those with nearly perfect eyesight throughout their lifetime will most likely encounter a vision problem as they age.

For some, it is a relatively minor problem, such as presbyopia - the loss of the ability to see small print and objects close up - which typically occurs in middle age. Remedies are straightforward, such as reading glasses, bifocals, or contact lenses fit in a "monovision" fashion so one eye is used mainly for distance vision, the other for near objects.

More serious problems are what eye-care experts call the "vision-robbers" that become more common with age: cataracts, glaucoma, and macular degeneration.

Due to the aging population, more Americans than ever are facing the threat of blindness due to these age-related diseases, according to a 2002 report by the National Eye Institute (NEI), in partnership with Prevent Blindness America.

More than 1 million Americans aged 40 and over are currently blind and another 2.4 million are visually impaired, the report says.

Because macular degeneration, glaucoma, and cataracts are some of the leading causes of blindness, eye-care experts are using June - designated Vision Research Month - to heighten awareness of these diseases.

Regular Eye Exams Counter Problems

While family history and environmental factors play a role in who does and does not eventually encounter a problem, there are preventive measures that can help reduce risk, or at least ensure the diseases are detected in early, more treatable stages.

"The best thing you can do is have regular eye exams by an eye-care professional," says Dr. Tim Wingert, an optometrist and acting director of the American Optometric Association's Clinical Care Group.

For those aged 40 to 64, eye-care experts recommend an exam every two years; after 65, an annual exam is recommended.

Those at higher risk or with early stages of vision disease may be advised to get more frequent exams, Dr. Wingert says.

Keeping yourself in the best possible health, and taking measures such as wearing sunglasses, can also help, eye experts say.

Cataracts Cloud the Eye

Of all the age-related vision diseases, cataracts - the clouding of the lens of the eye - are the least serious, mostly because the surgery to correct the problem has become so precise, experts say.

"Cataracts are not a threat the way others are," says Dr. Lylas Mogk, an ophthalmologist and director of the Visual Rehabilitation and Research Center of the Henry Ford Health System in Detroit.

More than 1 million cataract operations are performed annually in the US, according to Research to Prevent Blindness, a New York City-based organization that funds eye research.

Cataracts affect nearly 20.5 million Americans aged 65 and older, according to the NEI.

"You remove the lens and replace it [with an artificial lens]," Dr. Mogk says. "The skill level of the surgeon has to be terrific. The incision is minute, you don't even need to put a stitch in."

Glaucoma Elevates Pressure in the Eye

Glaucoma, a serious disease, affects about 2.2 million Americans who know they have it and another 2 million who do not yet know, according to estimates from the NEI.

Glaucoma can cause the fluid pressure within the eye to build up, and eventually it can damage the optic nerve. Eye-care experts test for glaucoma using a variety of methods, including the "puff test," in which a puff of air is directed toward the eye, to determine if intraocular pressures are normal.

Family history and racial background can drive up the risk of glaucoma, Wingert says, with African Americans at greater risk than other groups of people, although researchers are not sure why.

If treated early, the outlook for the glaucoma patients is good, Dr. Mogk says. "The vast majority of people with glaucoma can be treated and avoid having vision loss," he says.

Medication in drop form is the usual treatment, he says. Another option is surgery to create a tiny hole to drain excess fluid.

Macular Degeneration Affects Fine Vision

The biggest threat to vision is macular degeneration, Dr. Mogk says. More than 1.6 million Americans over age 60 have advanced macular degeneration, according to the NEI.

In this condition, the macula, a tiny area of the retina that allows clear central vision - which is crucial to such tasks as driving a car or reading - deteriorates.

There are two types of macular degeneration, known as wet and dry, Dr. Mogk says, adding, "Everyone starts as dry."

In the dry form, tiny white spots known as drusen develop in the eye. About 15 percent of those affected go on to develop the wet form, in which a network of blood vessels develops in the eye, leaks and gradually obstructs vision.

For the wet form is responsible for 10 percent of disease cases, but accounts for 90 percent of all severe vision loss caused by either type of AMD.

Wet AMD occurs when new blood vessels behind the retina start to grow beneath the retina where they leak fluid and blood and can create a large blind spot in the center of the visual field. If this happens, there is a marked disturbance of vision in a short period of time.

Treatment options include laser surgery to cauterize the blood vessels or photodynamic therapy, in which a drug activated by light destroys the abnormal vessels, Dr. Mogk says.

Nutritional supplements may help macular degeneration patients at risk of developing advanced stages of the disease, a study reported in 2001 suggests. In the study, published in the Archives of Ophthalmology, those who took a combination of vitamin C, vitamin E, beta-carotene, and zinc had less vision loss caused by the condition.

Patients should ask their eye doctor about whether the regimen might work for them and about the exact dose.

Always consult your physician for more information.

What Are the Different Types of Cataracts?

The American Academy of Ophthalmology describes the different types of cataracts according to the cataract location on the eye lens, including:

nuclear cataract
This is the most common type of cataract, and the most common type associated with aging. Nuclear cataracts develop in the center of the lens and can induce myopia, or nearsightedness - a temporary improvement in reading vision which is sometimes referred to as "second sight." Unfortunately, "second sight" disappears as the cataract grows.

cortical cataract
This type of cataract initially develops as wedge-shaped spokes in the cortex of the lens, with the spokes extending from the outside of the lens to the center. When these spokes reach the center of the lens they interfere with the transmission of light and cause glare and loss of contrast.

This type of cataract is frequently developed in persons with diabetes, and while it usually develops slowly, it may impair both distance and near vision so significantly that surgery is often suggested at an early stage.

subcapsular cataract
A subcapsular cataract usually starts as a small opacity under the capsule, at the back of the lens. This type of cataract develops slowly and significant symptoms may not occur until the cataract is well developed. A subcapsular cataract is often found in persons with diabetes, myopia, retinitis pigmentosa, and in those taking steroids.

Always consult your physician for more information.

What Are the Different Types of Glaucoma?

open-angle glaucoma
With this most common type of glaucoma, the fluid that normally flows through the pupil into the anterior chamber of the eye cannot get through the filtration area to the drainage canals, causing a build-up of pressure in the eye. Nearly 2.2 million Americans have been diagnosed with glaucoma, and almost 2 million do not know they have the disease.

low-tension or normal-tension glaucoma
While normal intraocular pressure ranges between 12 to 21 mm Hg, an individual may have glaucoma even if the pressure is within this range. This type of glaucoma presents optic nerve damage and narrowed side vision.

angle-closure glaucoma
In angle-closure glaucoma, the fluid at the front of the eye cannot reach the angle and leave the eye because the angle becomes blocked by part of the iris. This results in a sudden increase in pressure and is generally a medical emergency, requiring immediate treatment to improve the flow of fluid.

childhood glaucoma
Childhood glaucoma is a rare form of glaucoma that often develops in infancy, early childhood, or adolescence. Prompt medical treatment is important in preventing blindness.

congenital glaucoma
Congenital glaucoma, a type of childhood glaucoma, occurs in children born with defects in the angle of the eye that slow the normal drainage of fluid. Prompt medical treatment is important in preventing blindness.

primary glaucoma
Both open-angle and angle-closure glaucoma can be classified as primary or secondary. Primary glaucoma cannot be contributed to any known cause or risk factor.

secondary glaucoma
Both open-angle and angle-closure glaucoma can be classified as primary or secondary. Secondary glaucoma develops as a complication of another medical condition or injury. In rare cases, secondary glaucoma is a complication following another type of eye surgery.

Always consult your physician for more information.

What Is Age-Related Macular Degeneration (AMD)?

Age-related macular degeneration (AMD) is a disease that affects an individual's central vision. AMD is the most common cause of severe vision loss among people over 60. Because only the center of vision is affected, people rarely go blind from this disease. However, AMD can make it difficult of read, drive, or perform other daily activities that require fine, central vision.

AMD occurs when the macula, which is located in the center of the retina and provides sight in the center of the field of vision, begins to degenerate. With less of the macula working, central vision - which is necessary for driving, reading, recognizing faces, and performing close-up work - begins to deteriorate.

Always consult your physician for more information.

Online Resources

American Academy of Ophthalmology

American Council for Headache Education

Glaucoma Research Foundation

National Eye Institute (NEI)

National Institutes of Health (NIH)

National Institute for Neurological Disorders and Stroke (NINDS)

US Department of Heath and Human Services