Optical Coherence Tomography of Animal Models of Retinitis Pigmentosa: From Animal Studies to Clinical Applications

PURPOSE: The aim of this study was to understand the relationship between the findings of spectral-domain optical coherence tomography (SD-OCT) of previously reported animal models of retinitis pigmentosa (RP) associated with known genetic mutations and their background structural and functional changes. METHODS: We reviewed previous publications reporting the SD-OCT findings of animal models of RP and summarized the characteristic findings of SD-OCT in nine different animal models (RCS(–/–), RHO P23H, RHO S334ter, RHO(–/–), Rpe65(–/–), rp12, Pde6β(–/–) (rd1 and rd10), and Arr1(–/–)) of human RP. RESULTS: Despite the various abnormal structural changes found in these different animal models, progressive thinning of the outer nuclear layer (ONL) and hyperreflective change in the inner and outer segment (IS-OS) layers of the photoreceptors were commonly observed on SD-OCT. In the rapidly progressive severe photoreceptor degeneration seen in rd10 and Arr1(–/–) mice, the ONL appeared hyperreflective. Electroretinography revealed various degrees of disease severity in these animal models. Discussion and Conclusion: SD-OCT is sensitive enough to detect even mild changes in the photoreceptor OS. Conversely, SD-OCT cannot qualitatively differentiate the pathologic and functional differences in the photoreceptors associated with different genetic abnormalities, with the exception of the rapid progression of severe forms of photoreceptor degeneration. These findings can be of value to understand better the clinical findings and the heterogeneous degenerative processes in patients with RP.