Choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) is the leading cause of blindness among older Americans. Laser photocoagulation, the only proven treatment, is limited to a small subset of eyes with CNV. Even among patients treated with the laser, the average final visual acuity is 20/250 - 20/320. Since the 1970's, several retinal specialists have suggested that laser photocoagulation may delay or prevent the development of CNV in eyes that are at especially high risk because of the presence of drusen. Pilot studies of laser treatment for eyes with drusen are now underway in the United States, England, Australia, and Spain. There is a growing mass of evidence that laser photocoagulation can cause high risk drusen to disappear. However, there are no clinical data to determine whether this action results in decreased incidence of CNV and a corresponding reduction in rates of vision loss. Support is being requested for the planning of a multicenter clinical trial, the Choroidal Neovascularization Prevention Trial (CNVPT), to assess the safety and effectiveness of laser treatment in preventing loss of visual function due to CNV.
The specific aims of the multicenter, randomized clinical trial are to: 1) Evaluate laser treatment in comparison to observation within patients having high risk drusen in both eyes (Bilateral Drusen Substudy); 2) Evaluate laser treatment in comparison to observation among patients having one eye already affected by CNV and high risk drusen in the contralateral eye (Fellow Eye Substudy).
Specific aims to be accomplished during the time period covered by this application are: 1) Preparation of a complete manual of operations, set of data collection forms, clinic management aids, and photographic standards for CNVPT; 2) Develop procedures for the CNVPT Coordinating Center; 3) Develop procedures for the CNVPT Reading Center; 4) Further refine the design of the CNVPT through incorporating information generated from an ongoing pilot study; 5) Preparation of grant application for the CNVPT Chairman's Office, Coordinating Center, Reading Center, and clinical centers.
