Adaptive Optics-Transscleral Flood Illumination Imaging of Retinal Pigment Epithelium in Dry Age-Related Macular Degeneration

Adaptive optics-transscleral flood illumination (AO-TFI) is a novel imaging technique with potential for detecting retinal pigment epithelium (RPE) changes in dry age-related macular degeneration (AMD). This single-center prospective study evaluated its ability to visualize pathological features in AMD. AO-TFI images were acquired using the prototype Cellularis^® camera over six 5 × 5° macular zones in patients with good fixation and no exudative changes. Conventional imaging modalities, including spectral-domain optical coherence tomography (OCT), color fundus photography and fundus autofluorescence, were used for comparison. AO-TFI images were correlated with OCT using a custom method (Fiji software, v. 2.9). Eleven eyes of nine patients (70 ± 8.3 years) with early (n = 5), intermediate (n = 1) and atrophic (n = 5) AMD were analyzed. AO-TFI identified relevant patterns in dry AMD. RPE cell visibility was impaired in affected eyes, but AO-TFI distinguished cuticular drusen with hyporeflective centers and bright edges, large ill-defined drusen and stage 3 subretinal drusenoid deposits as prominent hyperreflective spots. It provided superior resolution for small drusen compared to OCT and revealed crystalline structures and hyporeflective dots in atrophic regions. Atrophic borders remained isoreflective unless RPE displacement was absent, allowing precise delineation. These findings highlight AO-TFI's potential as a sensitive imaging tool for characterizing early AMD and clinical research.