Choroidal thickness profile in Retinitis Pigmentosa – Correlation with outer retinal structures

AbstractPurposeTo compare the choroidal thickness (CT) of subjects with Retinitis Pigmentosa (RP) with age-matched healthy subjects and to correlate the visual acuity with retinal parameters including central macular thickness (CMT), inner segment/outer segment junction (IS/OS junction) integrity, external limiting membrane (ELM) integrity and choroidal thickness in subjects with RP.MethodsEighty-eight eyes (69 patients) with typical RP and 188 eyes of 104 healthy subjects were enrolled between September 2012 and January 2013.All subjects underwent a comprehensive ocular examination including choroidal imaging using enhanced depth imaging with spectral domain optical coherence tomography. Outcome measures were CT difference between RP and age-matched healthy subjects; and correlation of various factors such CMT, IS/OS junction integrity, ELM integrity, and CT with visual acuity.ResultsAmong RP subjects, mean age was 31.39±13.4years with a mean BCVA of 0.99±0.94logMAR. Mean spherical equivalent was −0.6±1.6D. Mean CMT was 148.48±119μm. Mean subfoveal CT was 296.9±72μm. Mean IS/OS and ELM integrity was 42.2±46.6% and 43.75±45.7%, respectively. The mean age was 40.0±13.5years with a mean spherical equivalent of 0.18±0.6D for the normal age-matched healthy group. Mean subfoveal CT was 283.1±47.8μm.CT at various locations in patients of various ages in the RP group did not show any statistical significant difference (P=≫0.05) in comparison with age-matched healthy subjects. On multivariate regression, ELM percentage integrity had the strongest association with best corrected visual acuity, followed by IS/OS junction percentage integrity. Subfoveal choroidal thickness had very weak correlation with visual acuity as well other retinal parameters.There was a significant difference in the outer retinal structure integrity (p=0.002) and CMT (p=0.02) between the eyes with good (⩾20/200) and poor vision (