Analysis of Spectral Domain - Optical Coherence Tomography and Fundus Autofluorescence in Typical Retinitis Pigmentosa.

ABSTRACT

Purpose: To study fundus autofluorescence (FAF) and spectral domain-optical coherence tomography (SD-OCT) characteristics in patients with typical retinitis pigmentosa (RP) and correlate them to visual acuity. Design: Retrospective observational case series. Methods: 110 eyes of 56 RP patients were included. FAF and SD-OCT imaging were done for all eyes. Extent of the autofluorescence ring, central foveal thickness, photoreceptor outer-segment length (PROS), foveal outer segment pigment epithelial thickness (FOSPET), and inner segment-outer segment (IS-OS) extent were defined and measured and correlated to logMAR best corrected visual acuity (BCVA) using linear regression. Results: Study included 110 eyes of 56 patients (34 male and 22 female). Mean BCVA was 0.33 logMAR with no difference between genders. The mean age of patients was 15.4 ± 15.1 years. Mean autofluorescence extent was 3590 ± 1994 μm horizontally, and 2880 ± 1836 μm vertically. These values were significantly correlated with preserved IS/OS junction extent (mean values horizontally = 2865 μm and vertically = 2464 μm). Mean central retinal thickness (218.74 μm) and PROS (44.85 μm) were significantly correlated to BCVA with correlation coefficient r = –0.189, P = 0.015; and r = –0.874, P = 0.0001, respectively. FOSPET (mean = 71.15 μm) did not show a significant correlation with BCVA, independent of PROS. Conclusions: Retinal microstructural changes as studied on SD-OCT, especially PROS length can be used as a surrogate marker to monitor degenerative diseases such as RP. Further, studies are required to clearly delineate the microstructuralfunctional relationship in the human retina.