Intereye Symmetry in Bietti Crystalline Dystrophy

PURPOSE: To evaluate anatomic and functional inter eye symmetry among individuals with Bietti crystalline dystrophy (BCD) using clinical and multimodal imaging methods, with a focus on the number, area, and distribution of the characteristic retinal crystalline deposits. DESIGN: Observational case series with prospective and retrospective data. METHODS: Setting : Multicenter. Study population : Thirteen Australian and New Zealand participants (26 eyes) with confirmed biallelic CYP4V2 mutations and a characteristic BCD fundus appearance. Procedures and main outcome measures : Crystals visible on color fundus photography were manually counted. Crystals were superimposed on aligned multimodal fundus images. Spearman's correlation coefficients (rho), intraclass correlation coefficients (ICCs), and Bland-Altman plots were used to quantify symmetry between eyes. Main outcome measures : Fundus crystal area and count, and absentautofluorescence (absent-AF) area. RESULTS: Median participant age was 48 years (interquartile range: 40-60 years). Intereye symmetry was high for fundus crystal area ( p = 1.00, 95% confidence interval [CI]: 1.00-1.00; ICC = 0.97, 95% CI: 0.880.99), fundus crystal count ( p = 0.98, 95% CI: 0.921.00; ICC = 0.97, 95% CI: 0.89-0.99), and absent AF area ( p = 0.88, 95% CI: 0.53-0.98; ICC = 0.98, 95% CI: 0.90-0.99). Average foveal volume, foveal crystal count and area, average and central foveal thickness, best corrected visual acuity, and average macular and central foveal sensitivity were not highly correlated between eyes. CONCLUSIONS: This study demonstrated strong inter eye symmetry measured by fundus crystal area, fundus crystal number, and absent-AF area. This may influence the choice of outcome measures for future therapeutic trials for BCD and provides valuable clinical information for ophthalmologists involved in the care and counseling of patients with BCD. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study evaluated the anatomic and functional symmetry between eyes in individuals with Bietti crystalline dystrophy (BCD) using clinical and multimodal imaging methods. The results showed high inter eye symmetry in terms of the number, area, and distribution of retinal crystalline deposits. This finding has important implications for future therapeutic trials and the care of BCD patients.