Subretinal Pigment Epithelium Illumination Combined With Focal Electroretinogram and Visual Acuity for Early Diagnosis and Prognosis of Non-Exudative Age-Related Macular Degeneration: New Insights for Personalized Medicine

PURPOSE: To evaluate the correlation between functional visual acuity and focal electroretinograms (fERGs) and morphological abnormalities in the retinal pigment epithelium and outer retinal atrophy (RORA) assessed by subretinal illumination (SRI) parameter at optical coherence tomography (OCT) examinations as signs of early disease in early and intermediate non-exudative age-related macular degeneration (ne-AMD). METHODS: One hundred forty-one eyes of 74 patients were retrospectively evaluated. A subgroup of patients (34/74) had a follow-up of at least 1 year. The study included both cross-sectional and longitudinal analyses. All eyes were assessed by OCT to measure the macular outer nuclear layer thickness, extent of ellipsoid zone interruption, absence or presence of drusen/reticular pseudodrusen in the foveal and perifoveal fields, and the SRI area closest to the fovea. Additionally, fERGs were performed. RESULTS: In the cross-sectional analysis, visual acuity and fERG amplitude were correlated (P < 0.01) with the SRI area. The fERG amplitude was correlated (P < 0.01) with the extent of ellipsoid zone interruption and tended to be lower in reticular pseudodrusen compared with drusen. In the longitudinal analysis, fERG amplitudes and outer retinal thickness tended to decrease on average by 15% and 18%, respectively, after 1 year of follow-up. The baseline RORA area, but not fERG amplitude or visual acuity, significantly predicted with 77% accuracy (P < 0.01) morphological deterioration, which was determined by an increase in the RORA area after 1 year. CONCLUSIONS: Functional visual acuity and its morphological correlations can be assessed in early and intermediate ne-AMD eyes. SRI, as a result of RORA, is a potential predictor of ne-AMD progression in a short-term follow-up. TRANSLATIONAL RELEVANCE: SRI assessment, an objective method to measure RORA, is a potential biomarker for non-exudative AMD progression.