Abstract
Purpose :
To correlate maturation of different hyper-reflective layers of outer retina with histologic morphology in WT swine using high resolution SD-OCT.
Methods :
Ultrahigh-resolution OCT images were acquired in-vivo in WT swine at days 2,8,16, and 30 using Bioptigen High resolution OCT machine (Leica Envisu R Class) at the level of macular streak 2 mm above optic nerve in both eyes. Animals then were sacrificed, eyes were enucleated, and tissue fixation with plastic embedding method was performed. Tissue blocks were cut 2 mm superior to the optic nerve (at the area of macular streak) in 4 micron sections using Reichert-Jung ultramicrotome. Crystal violet staining was performed and slides were reviewed under light microscope and carefully correlated with OCT images side by side.
Results :
Hyper-reflective layers of outer retina increase in width and intensity from birth to P30 which is compatible with cone maturation and photoreceptor outer segment elongation. Layers can be differentiated to ELM, cone ellipsoid, rod ellipsoid, RPE microvilli, and RPE cell bodies. It is different from human as the cone ellipsoid is visible as a separate hyper-reflective band secondary to orthogonal orientation of mitochondria.
Conclusions :
In vivo ophthalmic ultrahigh-resolution OCT imaging in the swine reveals separate cone and rod ellipsoid layers, in contrast to man, that allows independent investigation of survival and regeneration of Rod/Cone photoreceptors.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.