High-resolution in vivo imaging of the RPE mosaic in eyes with retinal disease

PURPOSE. To use high-resolution and contrast imaging techniques to reveal microscopic retinal structures, including individual retinal pigment epithelial (RPE) cells, in human eyes with inherited retinal disease. METHODS. Adaptive optics scanning laser ophthalmoscopy (AOSLO) was used to image the macular region in patients with retinal degenerative diseases, including two patients with cone-rod dystrophy and one with bilateral progressive maculopathy. Images were processed, and the microscopic details were analyzed. Fundus-related microperimetry was used to assess visual function within retinal regions where no cones were visible. RESULTS. In addition to patches of intact cone photoreceptors, AOSLO images revealed mosaics of RPE cells in regions where it appeared that cones were missing. In cone-rod dystrophy (CRD), the RPE cells were visualized in an annular region surrounding a cone-preserved central area. RPE cell shape, size, and distribution compared well with measurements from the literature. Fundus-related microperimetry results indicated scotomas that corresponded to the locations where RPE cells were visible. CONCLUSIONS. For the first time, the mosaic of RPE cells has been directly visualized by AOSLO. Patients with hereditary retinal degenerations causing cone loss in the macula allowed visualization of RPE cells in areas where cones were missing. Regions with visible RPE cells demonstrated loss of visual function measured using microperimetry.