Quantifications of Outer Retinal Bands in Geographic Atrophy by Comparing Superior Axial Resolution and Conventional OCT

Abstract

PURPOSE. Novel treatments for geographic atrophy (GA) require precise monitoring, which can be improved with advances in optical coherence tomography (OCT) technology. The purpose of this study was to investigate the benefits of a novel device with superior axial resolution. METHODS. Patients were recruited at the Department of Ophthalmology and Optometry at the Medical University of Vienna. Patients with GA were imaged with a Heidelberg SPECTRALIS HRA+OCT and the novel Heidelberg High-Res OCT device. Outer retinal bands and subretinal drusenoid deposits (SDDs) were segmented in 49 B-scans per OCT. Thickness and loss of outer retinal bands, as well as SDD volumes, were compared between devices and regions using linear mixed-effects models. RESULTS. The study included 3920 B-scans of 40 eyes of 32 patients. For the High-Res OCT, the myoid zone was thinner (19.85 μm, 95% confidence interval [CI] 16.8–22.8 vs. 21.37 μm, 95% CI 18.4–24.4; P < 0.001), whereas the ellipsoid zone (EZ) band was thicker (28.35 μm; 95% CI 22.7–24.0 vs. 27.29 μm, 95% CI 21.6–33.0). Smaller EZ- and external limiting membrane loss areas (all P < 0.001) were found for the High-Res OCT. The RPE band was thinner for the High-Res OCT (15.97 μm, 95% CI 13.5–18.4 vs. 21.08 μm, 95% CI 18.6–23.5; P < 0.001) without significant differences in RPE loss. Higher SDD volumes were found for the High-Res OCT (P < 0.001). CONCLUSIONS. Precise in vivo quantification of OCT features is of great relevance for individualized patient management. The High-Res OCT device allows for detailed topographical analysis of outer retinal changes in GA, which could improve early detection, patient selection, and patient management in clinical practice.