Optical Coherence Tomography of the Corn Snake (Pantherophis guttatus) Eye: An Exploratory Study

Abstract The aim of this exploratory study was to capture images of the anterior and posterior segments of the corn snake eye using spectral-domain optical coherence tomography (OCT). Postmortem OCT scans were conducted on three euthanized corn snakes ( Pantherophis guttatus ), followed by a histological examination of their eyes. OCT findings were correlated with histology to identify anterior and posterior ocular structures, and to delineate retinal layers on OCT. Total retinal thickness (RT) was manually measured every 360 μm from the edge of the optic disc over a 3,600-μm distance in the dorsal and ventral quadrant of each snake. In the anterior segment of the eye, OCT imaging successfully identified the spectacle, cornea, iris, lens, and Schlemm’s canal. The posterior segment scans revealed a vestigial conus papillaris and retinal folds adjacent to the optic nerve head, which were confirmed by histology. The membrana vasculosa was distinguishable from the surrounding retina, and despite some limitations in image resolution, retinal layers were discernible. There was a positive correlation between the total RT and the distance from the optic disc (with the retina being thicker farther from the optic disc). Additionally, the total RT in the ventral quadrant was significantly lower than in the dorsal quadrant. OCT imaging effectively identified various anatomical features and retinal layers of the corn snake’s eye. To establish comprehensive OCT references for the posterior segment of the eye, further studies involving healthy, living snakes are needed.