ABSTRACT
Purpose: To 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
Methods: Eighty-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
Results: Among RP subjects, mean age was 31.39 +/- 13.4 years with a mean BCVA of 0.99 +/- 0.94 logMAR. Mean spherical equivalent was -0.6 +/- 1.6D. Mean CMT was 148.48 +/- 119 micro m. Mean subfoveal CT was 296.9 +/- 72 micro m. Mean IS/OS and ELM integrity was 42.2 +/- 46.6% and 43.75 +/- 45.7%, respectively. The mean age was 40.0 +/- 13.5 years with a mean spherical equivalent of 0.18 +/- 0.6D for the normal age-matched healthy group. Mean subfoveal CT was 283.1 +/- 47.8 micro m. 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 [<20/200], but not in subfoveal choroidal thickness [p = 0.3]
Conclusions: Our study results did not show any significant difference in choroidal thickness between subjects with RP and agematched healthy subjects. Choroidal thickness correlated better with the age but not with the vision or outer retinal structures in eyes with RP. Outer retinal structure integrity and CMT had a better correlation with visual acuity