RESUMEN
OBJECTIVE: To investigate qualitative and quantitative differences in the structure of the posterior segment of the eye in 1-day post-hatch and 12-month-old retinal dysplasia and degeneration (rdd) and wild-type chickens. ANIMAL STUDIED: Retinal dysplasia and degeneration and wild-type chickens. PROCEDURE: Using a commercially available spectral domain optical coherence tomography (OCT) system, 15° horizontal line scans were performed in both eyes of 24 live birds. Qualitative differences in retinal lamination and choroidal structure were investigated, and retinal and choroidal thickness were measured. RESULTS: Progressive retinal thinning with loss of outer retinal lamination and changes in the appearance of the choroid were seen in the rdd birds. Mean total retinal thickness was 202 µm (SD 7.8) and 251 µm (SD 8.8) in the rdd and wild-type chicks and 154 µm (SD 18) and 280 µm (SD 10.8) in the adult birds. Much of the difference was the result of loss of outer retinal lamination and thickness in the rdd birds. Mean choroidal thickness was 76 µm (SD 19.6) and 112 µm (SD 36.9) in the rdd and wild-type chicks and 85 µm (SD 23.7) and 228 µm (SD 44.1) in the rdd and wild-type adult birds, respectively. CONCLUSIONS: Differences in retinal and choroidal structure and thickness between rdd and wild-type birds were evident on spectral domain OCT imaging at 1-day post-hatch and more marked at 1 year. Spectral domain OCT may provide a reliable end point for therapeutic intervention in this animal model of inherited retinal degeneration.