Abstract
Purpose :
Change in cone structure based on adaptive optics scanning laser ophthalmoscopy (AOSLO) has been suggested as an outcome for clinical trials in retinal degeneration. We assess cone structure changes using AOSLO in the Rate of Progression of USH2A-related Retinal Degeneration (RUSH2A) study, a multicenter natural history study.
Methods :
AOSLO images were acquired at 4 RUSH2A centers (1 eye per patient), twice at baseline and annually for 24 months. Eligible images had at least 10 regions of interest (ROIs) with > 50 contiguous cones. Images were analyzed by masked, independent graders (Figure 1). Cone spacing Z-scores (standard deviations from the normal mean at the measured location) were compared between graders and the 2 baseline images, and the annual rate of change was assessed using linear mixed effects regression models weighted by image quality score.
Results :
Among 31 consenting adults, two baseline images were obtained for 24 (77%). Fourteen eyes (58%) had images meeting eligibility criteria, yielding 192 ROIs. At baseline 71% of participants were male, with median age 38 years, median duration 12 years, and 43% had Usher syndrome. Variability among graders was greater in images with lower image quality score (P < 0.001). Cone spacing increased with eccentricity, quality score and disease duration (P < 0.03). On average, cone spacing Z-score increased 0.14 annually (about 9%, P < 0.001). We observed no significant differences in rate of change between disease type (Usher syndrome or retinitis pigmentosa), imaging site, or grader.
Conclusions :
Quantitative measures of cone structure showed some challenges in image acquisition and grading reproducibility, yet showed promise that AOSLO images can be used to characterize progressive change over 24 months in USH2A-related retinal degeneration. Additional multicenter studies utilizing AOSLO are needed to advance cone mosaic metrics as sensitive outcome measures for clinical trials.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.