BALTIMORE, Oct. 19 - A treatment regimen combining lasers and a light-sensitive medication appears to reduce the risk of vision loss in some patients with age-related macular degeneration, or AMD, according to a study of more than 600 patients at 22 medical centers across North America and Europe. In the study, led by Johns Hopkins University, researchers found that photodynamic therapy (PDT) reduced the risk of vision loss in certain patients with an aggressive wet form of macular degeneration in which abnormal leaky blood vessels and scar tissue grow across the center of the retina or light-sensitive portion of the eye. Results of the study can be found in the October issue of the journal Archives of Ophthalmology.