Quantification of Drusen in Macular Degeneration

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DESCRIPTION: (Applicant's Abstract) Age-related macular degeneration (AMD) is the most common cause of blindness in the United Sates in Americans over the age of 50. Drusen are by-products of rod and cone metabolism and their presence in the ocular fundus is a clinical sign of AMD. It is known that patients whose eyes harbor drusen are at special risk of visual loss from AMD. In a prospective, multi-centered trial, the Age-Related Eye Disease Study (AREDS), some 5000 patients have been enrolled and followed at six-month intervals to determine risk factors for AMD as well as to measure the influence of certain multivitamins and micronutrients on the progression of macular degeneration and cataract. In another prospective, randomized, controlled trial, the Prophylactic Treatment of AMD Trial (PTAMD), patients with multiple large drusen have been enrolled to determine whether a minimal laser treatment applied one time provides any benefit with respect to lowering rates of visual loss and rates of development of choroidal neovascularization (CNVM). During the PTAMD and AREDS trials, photographs of the fundi of each participant have been taken at least annually in the form of Ektachrome color slides. These slides are evaluated by human readers in a Reading Center and the extent of the drusen is categorized accordingly. The applicant proposes to perform a quantitative analysis on the color slides of the macula of all patients who have been enrolled into the PTAMD and AREDS trials at the Pittsburgh site, as well as other patients who have AMD and have been followed similarly for a minimum of three years. The original slides will be digitized onto CD disks for permanent archiving, and will be analyzed using a specially-written computer algorithm which semi-automatically detects drusen in digital images. Once detected, quantitative measurements of the area of drusen extent and size of each drusen are generated for each image. This method is more precise than characterizing drusen using traditional long and more subjective protocols, and may be valuable in determining the risks of a given patient developing choroidal neovascularization and visual loss before such events occur. That is, such continuous quantitative data may, when analyzed, provide a more accurate and sensitive assessment of risk compared to conventional measurement techniques.