EARLY clinical trials of an experimental treatment for the leading cause of blindness in developed countries have yielded encouraging although not yet convincing results.
In the trials, a majority of patients with age-related macular degeneration of the "wet" type, who received lowdose external beam radiation to halt the proliferation of blood vessels beneath their retinas, experienced stabilized or improved vision.
However, some ophthalmologists and others are not yet convinced that the improvement and stabilization of vision reported was a result of the treatment. Because the vision of patients with macular degeneration often stabilizes or improves without treatment, at least for a while, randomized controlled trials are necessary, they say, before this therapy can be considered effective.
2 Types of Disorder
There are 2 kinds of age-related macular degeneration, and the causes of both are unknown. The "wet" type is marked by a proliferation of blood vessels beneath the retina that