Age Related Macular Degeneration (AMD) The macula is a small area in the retina at the back of the eye that allows you to see fine details clearly and perform activities such as reading and driving. When the macula does not function correctly, your central vision can be affected by blurriness, dark areas or distortion. Macular degeneration affects your ability to see near and far, and can make some activities — like driving, threading a needle or reading — difficult or impossible. Although macular degeneration reduces vision in the central part of the retina, it usually does not affect the eye's side, or peripheral, vision. For example, you could see the outline of a clock but not be able to tell what time it is. Macular degeneration alone does not result in total blindness. Even in more advanced cases, people continue to have some useful vision and are often able to take care of themselves. In many cases, macular degeneration's impact on your vision can be minimal.
Deposits under the retina called drusen are a common feature of macular degeneration. Drusen alone usually do not cause vision loss, but when they increase in size or number, this generally indicates an increased risk of developing advanced AMD. People at risk for developing advanced AMD have significant drusen, prominent dry AMD, or abnormal blood vessels under the macula in one eye ("wet" form).
Diagnostic procedures used in diabetic retinopathy may include fluorescein angiography to determine the degree of ischemia or the presence of retinal vascular abnormalities. Ocular coherence tomography (OCT) is useful to determine the retinal thickness measurements. The OCT can be used longitudinally to determine whether the macular thickening is responding (swelling/ edema is decreasing) to treatment.
Along with the abnormal growth blood vessels, vascular endothelial growth factor (VEGF) is thought to play a big part in causing wet AMD. Anti-VEGF drugs target these proteins—preventing them from causing more damage and possibly even reversing their effects. To visualize this, imagine the roots of a tree growing and spreading until they actually uproot a sidewalk. Then imagine rainwater seeping up throughout the cracks. These abnormal blood vessels (the "roots") tend to be very fragile. They often grow, and leak or bleed, causing scarring of the macula. This damage to the macula results in rapid central vision loss. Anti-VEGF drugs stop the fragile roots from growing and spreading.
Macular degeneration can cause different symptoms in different people. The condition may be hardly noticeable in its early stages. Sometimes only one eye loses vision while the other eye continues to see well for many years. But when both eyes are affected, the loss of central vision may be noticed more quickly.
Following are some common ways vision loss is detected:
Many people do not realize that they have a macular problem until blurred vision becomes obvious. Your ophthalmologist can detect early stages of AMD during a medical eye examination that may include:
Although the exact causes of macular degeneration are not fully understood, antioxidant vitamins and zinc may reduce the impact of AMD in some people.
A large scientific study found that people at risk for developing advanced stages of AMD lowered their risk by about 25 percent when treated with a high-dose combination of vitamin C, vitamin E, beta carotene and zinc. Among those who have either no AMD or very early AMD, the supplements did not appear to provide an apparent benefit. It is very important to remember that vitamin supplements are not a cure for AMD, nor will they restore vision that you may have already lost from the disease. However, specific amounts of these supplements do play a key role in helping some people at high risk for advanced AMD to maintain their vision. You should speak with your ophthalmologist to determine if you are at risk for developing advanced AMD, and to learn if supplements are recommended for you.
Certain types of "wet" macular degeneration can be treated with laser surgery, a brief outpatient procedure that uses a focused beam of light to slow or stop leaking blood vessels that damage the macula. A treatment called photodynamic therapy (PDT) uses a combination of a special drug and laser treatment to slow or stop leaking blood vessels.
Another form of treatment targets a specific chemical in your body that is critical in causing abnormal blood vessels to grow under the retina. That chemical is called vascular endothelial growth factor (VEGF). Anti-VEGF drugs block the trouble-causing VEGF, reducing the growth of abnormal blood vessels and slowing their leakage.
These procedures may preserve more sight overall, though they are not cures that restore vision to normal. Despite advanced medical treatment, many people with macular degeneration still experience some vision loss.