Quantitative Analysis of Retinal Structure Using Spectral-Domain Optical Coherence Tomography in RPGR-Associated Retinopathy

PURPOSE: To quantify retinal structure and progression using spectral-domain optical coherence tomography (SDOCT) in patients with retinitis pigmentosa (RP) associated with retinitis pigmentosa GTPase regulator gene (RPGR) mutations. DESIGN: Retrospective observational case series. METHODS: Setting: Moorfields Eye Hospital, London, United Kingdom. SUBJECTS: Both eyes of 32 patients. SDOCT follow-up period of >1 year (3.1 1.4 years). MAIN OUTCOME MEASURES: Ellipsoid zone (EZ) width (EZW) and outer nuclear layer (ONL) and inner retinal layer (IRL) thickness measurements. Progression rates, interocular symmetry, and association with age and genotype were investigated. RESULTS: Significant differences were observed between baseline and final measurements of EZW and ONL thickness, but not for IRL thickness. Baseline and final EZWs were 2438 1646 mu m and 1901 1423 mu m for right eyes (P < .0001); 2420 1758 mu m and 1922 1482 mu m for left eyes (P < .0001). EZW constriction rates were 176.6 130.1 ?m/year and 173.1 146.8 mu m/year for right and left eyes. ONL thinning rates were 2.58 2.85 mu m/year and 2.52 3.54 mu m/year for right and left eyes. Interocular differences in EZW and ONL progression were not significant (P = .8609 and P = .6735, respectively). Strong correlations were found between EZW constriction rates of right and left eyes (r(s) = 0.627, P = .0002) and between EZW constriction and baseline EZW (r(s) = 0.714, P < .0001). There was moderate negative correlation between EZW constriction and age (r(s) = -0.532, P < .0001). Correlation between ONL thinning and age was not significant, as were differences between EZW and ONL progression rates with respect to genotype. CONCLUSIONS: This study provides SDOCT progression rates for RPGR-associated RP. There is overall interocular symmetry with implications for future treatment trials where 1 eye could serve as a control. (C) 2017 The Author(s). Published by Elsevier Inc.