BACKGROUND: In people over age 65, age-related macular degeneration is the leading cause of legal blindness in the United States. About 20 percent of people between 65 and 74-years-old in this country will have some degree of macular degeneration. The prevalence reaches as high as 30 percent in people over age 75.
There are two forms of macular degeneration: wet and dry. Dry macular degeneration is the most common and the least severe form, but wet macular degeneration accounts for most of the severe vision loss associated with the disease. Some patients with the dry form will eventually go on to develop the wet form. There are very few options as far as treatment for patients with dry macular degeneration.
NEW HELP FOR THE DRY FORM: Researchers across the country are testing a new laser, called the OcuLight laser, to determine if they can stop people with the dry form from progressing on to develop the wet form of the disease. The laser works by targeting drusen with light application of the laser.
Drusen are fatty materials that build up as mounds underneath the retina. These lumps can get quite large. Patients can develop progressive thinning of the retina and loss of vision. Eyes that have the largest drusen, the most number and the most packed together are know to have the highest risk of developing wet macular degeneration. The laser irritates the cell layer involved with keeping the health of the retina.
Researchers hope this will cause the body's reparative processes to come in and remove some of those drusen deposits. The laser works by actually heating up that cell layer, known as the retinal pigment epithelium.
"This laser is delivered at a light enough dose that we're hoping to deliver little or no energy to the retina itself and get most of the energy uptake and heating effect to the retinal pigment epithelium," said Gregory Fox, M.D., a retinal specialist involved in the study.
Dr. Fox says heating and damaging of the retinal pigment epithelium causes the body to do some repair work and at the same time, some of the drusen disappear and decrease in size, number, and thickness.
CAUTION AND IMPLICATIONS: Dr. Fox warns that the laser is intended for people who have dry macular degeneration only. In people who already had wet macular degeneration in one eye, studies show this laser actually caused an increased risk of wet macular degeneration in the other eye when treated. However, studies so far show success in people who only have the dry form of the disease.
"We could decrease the incidence of patients going on to wet macular degeneration by the order of 100,000 patients or more per year," Dr. Fox said.
Because the laser is not a drug, it does not need to await FDA approval. Dr. Fox says when results of the studies are collected and analyzed and researchers can prove it truly is a beneficial treatment, then it could be a treatment that insurance companies would pay for in the future.
The study is no longer enrolling patients. The current study of 800 patients is still ongoing at 21 locations across the country.
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