Abstract
Purpose :
To detect morphologic changes in the outer retina during diurnal shedding of rod outer segments (study 1) and dark-light adaptation (study 2) using a novel high resolution optical coherence tomography (High-Res OCT) device.
Methods :
In this observational study, 14 healthy subjects were enrolled and macular B-scans were acquired with the SPECTRALIS® High-Res OCT (Heidelberg Engineering, Heidelberg, Germany). 10 of the subjects received morning and evening imaging (study 1) and 5 of them underwent dark adaptation followed by bleaching and daylight exposure (study 2).
Results :
Morning-evening analysis in study 1 revealed a significant reduction in outer retinal thickness induced by shortening of the rod outer segments, whereas the retinal pigment epithelium and Bruch’s membrane complex (RPE-BM complex) remained unchanged.
Study 2 showed that light exposure in the dark-adapted retina caused a significant transient increase in outer retinal thickness, attributable to an enhancement of the RPE-BM complex and to an elongation of the photoreceptor outer segments (POS). Additionally, an increase in reflectivity of the second and third hyperreflective outer bands (ellipsoidal zone and interdigital zone) was observed upon bleaching.
Conclusions :
Due to its superior axial resolution, High-Res OCT has the capability to detect diurnal and light-related thickness and reflectance adaptation processes in the outer retina, especially in the POS, at the micrometer scale. These results could play an impactful role in routine clinical practice for understanding and evaluating OCT signals from the outer retinal bands and aid in the assessment of photoreceptor function and retinal diseases.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.