Macular Degeneration

Macular degeneration is a disease in which central vision is drastically effected due to the breakdown of the central retinal tissues.

The reduction in central visual acuity can be due to a slowly progressive “drying out” of the macular area, or secondary to abnormal vessel growth leading to a “wet” form of the disease, which is more damaging to functional vision.

Since the central vision is affected, patients will have symptoms ranging from mild central vision distortions to central blindness. While there is no known cure for macular degeneration, some vitamin supplements, proper diet, and not smoking can possibly aid in preventing the advancement of macular degeneration.

Laser Treatment for Wet AMD

A small number of people suffering from the "wet" form of macular degeneration — 10-15 percent — may be helped by laser treatment. But even for this relatively small group, it does not restore vision that is already lost. For those who are suitable candidates for this procedure, laser treatment seals the abnormal leaking blood vessels in the retina and discourages their growth. In about half of these cases, however, the aging process may cause new blood vessels to grow in nearby areas. This suggests that perhaps half of these patients may require additional laser treatment at some time in the future. Nevertheless, it should be noted that abnormal vessels, if not treated at all, will continue to grow larger and to leak even more, causing continuing loss of vision.

Visudyne® Photodynamic Therapy (PDT) for Wet AMD

Visudyne® therapy is being used to treat thousands of patients with "classic" wet AMD. It is also being tested for patients with "occult" wet AMD. These terms refer to the way the retina looks - how clearly defined is the lesion or area of atrophy.

The benefit of photodynamic therapy (PDT) is that it does not destroy the adjacent cells like conventional laser treatment. In PDT, a dye that reacts to light is injected into the patient's arm. As the dye moves up to the eye and passes through the body, it pools in those damaged new blood vessels of the retina. A different kind of laser with a lower power (a cold laser) is used. When the dye is exposed to the laser, it seals off the leaking vessels. Since the dye does not stay in the healthy tissue or get to the retinal cells, they do not react to the laser. However, since the dye remains in the body for several days, patients must stay out of the sun and cover up carefully on their trip home from the ophthalmologist or they will get severe sunburn. Otherwise, few side effects or complications have been reported and the treatment is quite successful for selected patients.

Visudyne® has been approved for classic wet AMD and for pathological myopia. In the U.S it is being considered for approval for minimally "classic" and for the "occult" form of wet AMD, which is much more common. Other drugs also are being explored.

Macugen®

Approved in the U.S. in December 2004, and in May 2005 in Canada and Brazil, Macugen® is designed to stop the growth of blood vessels.

The drug is injected into the eye every six weeks. The study followed patients on this schedule for two years. If the drug is successful, the blood vessels that leak and bleed and cause vision loss will no longer grow into the macula. Further laser treatment would not be necessary.

Treatment for Dry AMD

There is no treatment currently for dry macular degeneration. Vitamins may make a difference for those with intermediate dry AMD. There are several experimental treatments under investigation as well.