Ultra-high resolution OCT imaging reveals retinal layer degeneration in RD10 mice with comparison to commercial standard resolution OCT.

Optical coherence tomography (OCT) imaging gives researchers a window into the structure-function relationships of the retina. This makes OCT a great tool for studying photoreceptor degeneration in vivo in mouse models of inherited retinal diseases like retinitis pigmentosa (RP). RP is a leading cause of blindness in individuals under 40 and has no approved treatment. In this study, we present a custom ultra-high resolution spectral domain optical coherence tomography (UHR-OCT) system for imaging the mouse retina with an axial resolution of 2.38 µm in air. First, we qualitatively and quantitatively compared imaging performance of our UHR-OCT to a commercially available OCT system (Heidelberg Spectralis OCT) and demonstrated that our system can resolve additional fine retinal cell layers compared to the commercial system and accurately measure their thickness. Using our UHR-OCT system, we measured thickness changes in retinal cell layers in retinal degeneration 10 (RD10) and compared them to those of wild type (WT) mice. We showed that RD10 mice have thinner retinas than WT mice, and that this retinal thinning was primarily associated with thinning of the outer nuclear layer and degradation of the photoreceptor inner and outer segment. This study demonstrates the utility of UHR-OCT for imaging fine retinal cell layers in the mouse retina with high resolution. Higher resolution OCT for mouse imaging could help researchers better understand inherited retinal diseases like RP in mouse models.