Abstract
Abstract: :
Purpose: To retrospectively describe the surface area of the pigment epithelial defect observed after transretinal removal of subfoveal classic neovascular membranes in age–related macular degeneration. Methods: Digital fluorescein angiograms had been obtained before and after submacular surgery for exsudative age–related macular degeneration in 17 eyes of 17 patients. Pre–operative membrane surface area and post–operative pigment epithelial defect were measured using the ImageNet software, in square millimeters. Results: Average pre–operative membrane surface area was 6.18 mm² +/– 4.16 (range 1.3 to 15.4 mm²). Average post–operative membrane surface area was 11.29 mm² +/– 4.66 (range 4.1 to 20 mm²). The graph of pre–operative (x) versus post–operative (y) surface areas showed a log–type regression curve, with pre–operative and post–operative surface areas tending to merge as size increased. Assuming a circular shape, with the formula: (surface) = 3.14 * (radius)², average pre–operative radius was 1.40 mm, and average post–operative radius was 1.89 mm. Conclusions: In a small retrospective study of submacular surgery results in age–related macular degeneration, classic neovascular membrane extension into the pigment epithelium, as deduced by surface area of post–operative pigment epithelial defect, was found to be 0.49 mm on all sides, on average. This is close to the 500 µm safety margin indicated for spot size overlap beyond lesion limits when treating patients by PDT for the same disease.
Keywords: age-related macular degeneration • choroid: neovascularization • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)