Adaptive optics imaging in age‐related macular degeneration

Purpose To document cases of drusen and age-related geographic atrophy(GA) at the microscopic scale using adaptive optics(AO). Methods Four cases of age-related drusens, 2 cases of familial drusen and 7 patients of GA underwent en face retinal imaging by AO retinal camera(rtx1, Imagine Eyes, Orsay, France). AO images were confronted to high-resolution spectral-domain optical coherence tomography(OCT) and scanning laser ophthalmoscopy(SLO) examinations. Results In AO images, most drusen appeared as doughnut-shaped highly reflective zones, and were better delineated than by color fundus photograph. The overlying cone mosaic could be detected over most of them, including their top. Between drusen, the cone photoreceptor mosaic appeared normal. In GA cases, AO images revealed irregular patches of multiple cone-like bright spots as well as larger dark disks in atrophic areas. Conclusion AO provided images of microscopic structures in various types of AMD, including GA. Local losses in cone contrast at the drusen slopes confirmed a strong relation between cone visibility and their orientation. There was no evidence of cone loss in association to drusen. In GA patients, our findings suggest that photoreceptors with shortened outer segments may survive within atrophic areas, which may lead to the development of novel therapeutic strategies aimed at restoring the function of surviving cones. These results demonstrate that AO retinal camera can detect isolated residual photoreceptors, and hence that it will be a powerful tool for quantifying spontaneous or therapeutic changes in AMD patients. Supported by ANR through Tecsan Program (project iPhot n° ANR-09-TECS-009)