My wife is a victim of macular degeneration. She has very low vision, can't drive, etc. What research, if any, is being done on this terrible affliction? Is there anything new she can try?

L.D.

The retina is a delicate layer of vision cells that lines the inside wall of the back of the eye. The central area of the retina responsible for straight-ahead vision, such as that involved in driving and reading, is called the macula.

Age-related macular degeneration is a disease that affects the central vision by damaging the vision cells of the macula. It is the main cause of vision loss in people over age 65. Because peripheral vision is usually not affected, people with macular degeneration can usually walk without a cane.

The most severe form of macular degeneration, called the "wet" form, is characterized by the growth of abnormal vessels beneath the retina. These abnormal vessels can leak fluid and blood into the retina, eventually causing permanent vision loss.

Currently, the standard treatment, called laser photocoagulation, involves using a thermal laser to destroy the abnormal vessels as soon as possible. Unfortunately, the surrounding retina is often damaged in the procedure, causing permanent loss of vision. Furthermore, the chance of blood-vessel leakage recurring after laser treatment is 50 percent.

An exciting new method of treating macular degeneration, called photodynamic therapy, is now under review by the Food and Drug Administration. In the treatment, a chemical called Visudyne (verteporfin) is injected into the abnormal blood vessels beneath the retina. Then, a non-thermal laser is used to activate the chemical, which destroys the abnormal vessels while leaving normal vessels and the retina untouched. However, because photodynamic therapy cannot restore damaged retinal cells, it will not help people who have already gone blind from macular degeneration.

It's very important for people with early stages of macular degeneration to screen their eyes every morning. (Your local eye doctor should have plenty of samples of these screening tests). If you do develop abnormal blood vessels in the macula, your ophthalmologist will generally be able to find this on a routine eye exam.

I truly hope that some day we develop a method for restoring sight to people who have lost their vision from macular degeneration. At this time, a true cure appears years to decades away.