Photopic and Scotopic Fine Matrix Mapping of Retinal Areas of Increased Autofluorescence in Patients with Age-Related Maculopathy (ARM) and Macular Degeneration (AMD)

Abstract

Abstract: : Purpose: To investigate photopic and scotopic sensitivity of retinal areas that show increased fundus autofluorescence (FAF) in patients with ARM and AMD. Methods: FAF was imaged using a modified confocal scanning laser ophthalmoscope (Zeiss prototype SM 30-4024). The retinal location for fixation was determined, and the fixation stability was calculated as a bivariate contour ellipse area (BCEA). The fine matrix mapping (FFM) was performed using a modified Humphrey field analyzer. Photopic and scotopic thresholds were obtained at 100 locations on a 9° by 9° matrix of 1° spacing centered at a macular area of increased FAF. Inclusion criteria included ARM or AMD fundus changes, areas of increased FAF, central and stable fixation, and a visual acuity of 20/40 or better. Results: FAF images were reviewed in 436 ARM and AMD patients. 38 patients met the inclusion criteria. In seven eyes of seven patients, FFM was performed. Two AMD patients had limited geographic atrophy (GA) and 2 had choroidal neovascularization (CNV). Soft drusen only were present in three ARM patients. In the GA patients, the areas of increased FAF (adjacent to RPE atrophy) showed normal or near normal photopic but severely reduced scotopic sensitivity. Similarly, areas of increased FAF in patients with CNV showed near normal photopic but severely reduced scotopic sensitivity. The central area of increased FAF corresponding to a large foveal soft druse in an ARM patient showed moderately reduced photopic and severely reduced scotopic sensitivity. In the other ARM patients with drusen, areas of increased FAF showed normal or near normal photopic sensitivity, but moderately reduced scotopic sensitivity. Conclusions: In retinal areas of increased FAF in ARM and AMD patients, scotopic sensitivity loss considerably exceeds photopic sensitivity loss. These areas indicate moderate to severe scotopic sensitivity loss, whereas photopic sensitivity can be normal. This finding is in line with histological data that have demonstrated a preferential loss of rods in ARM and AMD. The study shows that increased FAF in ARM and AMD has a functional correlate.

Keywords: age-related macular degeneration • macula/fovea • imaging/image analysis: clinical