Assessment of local sensitivity in incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) lesions in intermediate age-related macular degeneration (iAMD).

Lesions of incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) are associated with disease progression in age-related macular degeneration. However, the corresponding functional impact of these precursor lesions is unknown.We present a cross-sectional study of four patients employing clinical-grade MAIA (stimulus size: 0.43°, ~125 µm) and adaptive optics scanning light ophthalmoscope (AOSLO, stimulus size 0.07°, ~20 µm) based microperimetry (MP) to assess the specific impact of iRORA lesions on retinal sensitivity.AOSLO imaging showed overall reduced photoreceptor reflectivity and patches of hyporeflective regions at drusen with interspersed hyper-reflective foci in iRORA regions. MAIA-MP yielded an average retinal sensitivity loss of -7.3±3.1 dB at iRORA lesions compared with the in-eye control. With AOSLO-MP, the corresponding sensitivity loss was 20.1±4.8 dB.We demonstrated that iRORA lesions are associated with a severe impairment in retinal sensitivity. Larger cohort studies will be necessary to validate our findings.

Cone Density Is Correlated to Outer Segment Length and Retinal Thickness in the Human Foveola.

Purpose: Assessment of the relationship between in vivo foveolar cone density, cone outer segment length (OSL), and foveal retinal thickness (RT). Methods: Foveolar cone density maps covering the central ±300 µm of the retina were derived from adaptive optics scanning laser ophthalmoscopy images. The corresponding maps of foveal cone OSL and RT were derived from high-resolution optical coherence tomography volume scans. Alignment of the two-dimensional maps containing OSL and RT with the cone density map was achieved by placing the location of maximum OSL on the cone density centroid (CDC). Results: Across 10 participants (27 ± 9 years; 6 female), cone density at the CDC was found to be between 147,038 and 215,681 cones/mm². The maximum OSL and minimum RT were found to lie between 31 and 40, and 193 and 226 µm, respectively. A significant correlation was observed between cone density at the CDC and maximum OSL (P = 0.001), as well as the minimal RT (P < 0.05). Across all participants, the best fit for the relationship between normalized cone density and normalized OSL within the central 300 µm was given by a quadratic function. Conclusions: Using optical coherence tomography-derived measurements of OSL enables to estimate CDC cone density and two-dimensional foveal cone density maps for example in patient eyes unsuitable for adaptive optics imaging. Furthermore, the observation of a fixed relationship between the normalized OSL and cone density points to a conserved mechanism shaping the foveal pit.

Supernormal foveal photoreceptor density in Alport syndrome: A case report.

PURPOSE: To investigate foveal photoreceptor configuration in Alport syndrome, a rare inherited disease characterized by Collagen IV dysfunction. METHODS: Adaptive optics scanning laser ophthalmoscope (AOSLO) in vivo imaging of the foveal center and quantitative analysis of cone photoreceptor topography in a 17-year-old male patient with Alport syndrome presenting absence of a foveal avascular zone (FAZ) and foveal hypoplasia in both eyes. RESULTS: Cone density analysis based on AOSLO images revealed an unusual linear cone topography profile displaying supernormal densities within the fovea (z-scores up to + 3.57 and + 2.97 in right and left eyes, respectively). CONCLUSION: Foveal hypoplasia has previously been associated with normal or reduced cone density. Our observation is the first case of disease-related supernormal cone density within the foveola, shedding light upon the role of Collagen IV in foveal maturation.