Correlation of Outer Retinal Degeneration and Choriocapillaris Loss in Stargardt Disease Using En Face Optical Coherence Tomography and Optical Coherence Tomography Angiography

Purpose Measure and correlate degeneration of the inner segment/outer segment junction (IS/OS), retinal pigment epithelium (RPE) and choriocapillaris (CC) in Stargardt disease (STGD) Design Prospective cross-sectional study Methods Setting Casey Eye Institute Population 23 patients with STGD Procedures OCT angiography (OCTA) scans were centered on the fovea. OCT slab projection and en face boundary maps were used to create masks to measure total IS/OS loss or RPE atrophy, as well as regions of isolated IS/OS loss, isolated RPE atrophy, matched IS/OS and RPE degeneration, or intact IS/OS and RPE. CC vascular density (CCVD) was quantified from CC angiogram. Outcome Measures Area of loss and CCVD for different region types of degeneration were quantified and correlated. Results The total area of IS/OS loss was strongly correlated with total area of RPE atrophy (r=0.96, p 2 =0.90). CCVD within regions of matched degeneration (85.6±2.7%; p Conclusions Photoreceptor and RPE degeneration exhibit a strong relationship wherein IS/OS loss is 1.6 fold greater than RPE atrophy, supporting the theory that photoreceptor degeneration precedes RPE in STGD. Both photoreceptor and RPE degeneration contribute synergistically to CCVD attenuation, but extra-lesional CCVD also tended to be abnormal. The findings and techniques in this study may be of utility in developing endpoints for clinical trials.