Choroidal thickness profiles in retinitis pigmentosa

Background Little quantitative information exists regarding the effect that retinitis pigmentosa (RP) has on the choroid. The aim of this study was to determine choroidal thickness profiles in patients with RP. Design Prospective. Participants Forty-two RP and 22 control subjects participated in the study. RP patients had mild to severe disease, with a visual acuity range of logMAR 0.1 to no light perception. Methods Images of the retina and choroid were obtained using the enhanced depth-imaging method and optical coherence tomography (OCT). Choroidal thickness measures were determined via manual segmentation of the OCT image. Main Outcome Measures The thickness profiles of the normal and RP groups were compared. The associations between choroidal thickness, visual acuity and duration of RP were determined. Results The choroid was thickest in the control eyes at the subfoveal location (336.60 +/- 70.42m), and the thickness gradually decreased towards the peripheral retina (temporal 8 degrees=295.55 +/- 60.52m; nasal 8 degrees=251.68 +/- 49.93m). In RP, the mean thickness was also greater at the fovea (215.60 +/- 94.91m) than the temporal (191.66 +/- 72.42m) and nasal (149.91 +/- 57.42m) retina, but all values were significantly lower than those of the controls (P0.001). Subfoveal choroidal thickness was significantly correlated with visual acuity (r=-0.46, P<0.001) and duration of disease (r=-0.4, P=0.001). Conclusions Patients with RP have a thinner choroid than controls. Patients with poorer visual acuity or longer duration of symptoms tended to have thinner choroids. Knowledge of choroidal thickness profile in RP is important for the field of restorative vision research and the development of suprachoroidal retinal prostheses.