Authors:  Ian C. Han, MD1; S. Scott Whitmore, PhD1; D. Brice Critser, BS, CRA1; Edwin M. Stone, MD, PhD1

Author Affiliations: 1Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA 52242

Purpose:  Choroideremia is an X-linked condition characterized by profound choroidal thinning and outer retinal loss which typically begin peripherally and spare the central macula until later in the disease course. The depth of imaging and wide field of view enabled by swept-source optical coherence tomography (SS-OCT) and angiography (SS-OCTA) may be advantageous for characterizing the extent of pathology deep to the choroid and beyond the macula. We aim to describe SS-OCT and SS-OCTA findings in a cohort of patients with choroideremia.

Methods: This is a retrospective, cross-sectional study of consecutive patients with molecularly-confirmed choroideremia seen at a tertiary referral center from September 12, 2017 to September 11, 2018. All patients underwent complete ophthalmic examination with multimodal imaging, including 12×12 mm SS-OCT/ OCTA (PLEX Elite 9000; Carl-Zeiss Meditec Inc, Dublin, California).Imageswere analyzed for structural and vascular abnormalities with attention to the presence of scleral tunnels, outer retinal tubulations, and choroidal vascular loss.

Results: Twenty-four eyes from12 male patients (mean age 42 years, range 7-75) were imaged for the study. Two eyes from a single patient were excluded due to poor image quality. Median best-corrected visual acuity was 20/32 (range 20/20 to light perception). Scleral tunnels (e.g., Figure 1, arrow) were seen in 54.5% (12/22) of eyes and were bilateral in all cases. Outer retinal tubulations were seen in 81.2% (18/22) of eyes, and their geographic distribution was easily visualized on en face imaging (e.g., Figure 2A). All eyes had profound loss of small-caliber choroidal vasculature on SS-OCTA (e.g., Figure 2B). The distribution of outer retinal tubulations (e.g., Figure 2C, blue area overlay) correlated well with areas of preserved choroidal vasculature.

Conclusions: Wide-fieldSS-OCT and SS-OCTA enable detailed visualization of structural and vascular pathology in choroideremia. Further characterization of these changes over time may be useful for providing insight into disease pathogenesis and for monitoring disease progression or treatment response in clinical trials.

Financial Disclosures: No authors have any conflicts of interest to disclose.