Age-Related Eye Diseases
The purpose of routine eye exams is not just to get an updated prescription for your eyeglasses or contact lenses: Eye exams are an important part of your health maintenance.
This is especially true for people over age 40, who have a greater risk of age-related eye diseases. Here is a brief summary of major eye problems that increase in frequency with age:
Glaucoma
Glaucoma is a variety of related conditions that cause damage to the optic nerve, which transmits visual information from the eye to the brain. Though glaucoma can affect people of any age, risk increases with age, particularly after age 40.
High eye pressure — either because too much fluid is produced in the eye or because the intraocular fluid (called the aqueous) drains too slowly from the eye — usually is the underlying cause of glaucoma.
In most cases, there are no glaucoma symptoms until noticeable vision loss occurs. For this reason, glaucoma sometimes is called the "silent thief of sight."
High eye pressure and glaucoma usually are detected during a routine eye exam. Glaucoma tests commonly used during an eye exam include the "air puff" machine, which indirectly measures your eye pressure with a gentle (though startling) puff of air to the surface of your eye.
If your eye doctor determines you have glaucoma or are at high risk of the disease because of elevated eye pressure, he or she will recommend treatment. The most common glaucoma treatment is medicated eye drops, though sometimes glaucoma surgery is recommended.
Glaucoma eye drops are designed to reduce eye pressure by lowering the rate of fluid production in the eye or increasing fluid outflow from the eye. Glaucoma surgery usually is designed to increase fluid outflow and might be recommended instead of eye drops or as an additional treatment.
Cataracts
A cataract is a clouding of the lens inside the eye, which is located behind the pupil and iris (the circular structure that surrounds the pupil and gives the eye its color).
Approximately 20.5 million Americans age 40 or older in 2004 had cataracts in at least one eye, and this number is expected to rise to 30.1 million by 2020, according to the National Eye Institute.
Cataract surgery currently is the only recognized treatment for cataracts.
In cataract surgery, the surgeon removes the eye's cloudy lens and replaces it with a clear intraocular lens (IOL) implant. A cataract operation takes only a few minutes and is very successful in most cases.
Modern IOLs used in cataract eye surgery include multifocal IOLs and accommodating IOLs that are designed to restore vision at all distances and reduce your need for reading glasses after cataract removal.
Crystalens currently is the only FDA-approved accommodating IOL for use in cataract surgery performed in the United States. There are several FDA-approved multifocal lenses, including ReSTOR and Tecnis multifocals.
Diabetic Retinopathy
Diabetic retinopathy is damage to the retina and retinal blood vessels caused by diabetes. In most cases, it occurs as the result of long-standing or uncontrolled diabetes. Diabetic retinopathy currently is the leading cause of blindness from eye disease among Americans under age 65.
Diabetes (Type 1 and Type 2) can cause serious damage to blood vessels that nourish the retina, causing them to leak blood into the eye. If significant bleeding occurs in the eye, a surgical treatment called vitrectomy may be needed to remove the blood to restore vision.
Diabetic retinopathy treatment usually consists of managing the underlying disease by controlling blood sugar levels through diet, exercise and oral or injected medication. In some cases, laser eye surgery is performed to seal leaking blood vessels in the eye or increase blood flow to the central part of the retina that is critical for good vision.
Macular Degeneration
Macular degeneration is a common age-related eye disease characterized by progressive damage to the central retina (macula) and loss of central vision.
The macula is the most sensitive part of the central retina and is responsible for visual acuity and color perception. Central vision loss from macular degeneration can make it impossible to drive, read, watch TV and do virtually anything that requires sharp, focused vision.
An Amsler grid is a simple screening device used to rule out and monitor vision changes caused by macular degeneration. It is simply a card or piece of paper with a square grid pattern of straight lines and a small black dot (fixation point) in the center of the grid. If lines on the grid look wavy or distorted when you are looking at the fixation point, you might have macular degeneration (also called AMD).
If a vision problem is detected with the Amsler grid, a more detailed visual field test may be performed to determine if vision loss from macular degeneration has occurred.
Like glaucoma and diabetic retinopathy, AMD can cause permanent vision loss. New drugs are being developed and used for macular degeneration treatment and show some promise in reducing vision loss from the disease in many patients.
Many people with vision loss from macular degeneration are considered to have low vision. This is the term used to describe significantly impaired vision in both eyes (usually worse than 20/60) that cannot be corrected with eyeglasses, contact lenses or refractive surgery.
Low vision aids are optical devices that help people with impaired vision use their remaining vision as efficiently as possible. Examples of low vision aids include magnifiers and telescopes that might be mounted on special eyeglass frames. Extra-powerful reading glasses also can be considered a low vision aid.
There also are many hand-held and stationary low vision aids, including computer-based magnifiers and lighted tabletop magnifiers.
If you have low vision your eye doctor may refer you to a low vision specialist. Usually this person is an optometrist who specialized in low vision eye exams and evaluations. This specialist can determine the best low vision aids for your needs and teach you how to use magnifiers, telescopes and other low vision products.
Preventing Age-Related Eye Diseases
Maintaining a healthy, active lifestyle can reduce your risk for age-related eye diseases like cataracts, macular degeneration and diabetic retinopathy. Studies have shown that obesity and a poor diet significantly increases your risk of vision problems later in life, and it appears that good nutrition and plenty of exercise are key to a lifetime of good vision.
It also is very important to have routine eye exams — even if you aren't experiencing vision problems. Your eye doctor can detect warning signs of glaucoma and other problems and may be able to help you prevent or lessen vision loss age-related eye diseases.