Correlation of Optical Coherence Tomography and Retinal Histology in Normal and Pro23His Retinal Degeneration Pig

PURPOSE: We correlate optical coherence tomography (OCT) retinal layer thickness measurements with histology in wild-type and retinal degenerative pigs. METHODS: OCT scans were obtained using the Bioptigen Envisu R2200. In normal pigs, three eyes were imaged in vivo, and three eyes were imaged after enucleation. In the Pro23His retinal degeneration pigs (P23H), one eye was imaged in vivo and four eyes were imaged after enucleation. All eyes were fixed in 4% paraformaldehyde and processed for histology. Corresponding retinal locations on OCT and histology were identified using anatomic landmarks (optic nerve, retinal vessels, visual streak). Individual retinal layer thicknesses were measured by two independent, masked graders, and intraclass correlation coefficients were used to determine agreement. OCT and histologic retinal thickness measurements were averaged and compared. RESULTS: OCT and histologic measurements correlated highly in normal and diseased eyes (R(2) = 0.91 and 0.92, respectively), and scans performed in vivo and ex vivo did not differ significantly. Despite good overall correlation, certain individual retinal layers (e.g., retinal nerve fiber layer [NFL], inner [INL] and outer [ONL] nuclear layers) appeared thicker on OCT compared to histology, while other layers (e.g., retinal pigment epithelium) appeared thinner. No statistically significant difference was found between OCT and histology for any retinal layer thickness measurement. CONCLUSIONS: Retinal layer thickness measurements correlate well with histology in pig eyes, but differences in individual retinal layers may be seen. TRANSLATIONAL RELEVANCE: OCT may be used in pigs to measure retinal thicknesses with good overall correlation to histologic measurements.