IMPACT OF ANISOMETROPIA ON DIABETIC RETINOPATHY PROGRESSION

Purpose: To investigate the impact of myopic changes on diabetic retinopathy progression by comparing Early Treatment Diabetic Retinopathy Study (ETDRS) grading scores and optical coherence tomography biomarkers between the eyes with anisometropia. Methods: This observational cross-sectional study retrospectively reviewed clinical records of anisometropia patients with diabetic retinopathy. The ETDRS grading scores and optical coherence tomography biomarkers, including central subfield thickness, subfoveal choroidal thickness (SFCT), presence of subretinal fluid, cystoid changes in the outer nuclear layer and inner nuclear layer, hyperreflective foci, ellipsoid zone continuity, the continuity of the external limiting membrane, disorganization of retinal inner layers of disorganization of retinal inner layers, and vitreomacular interface changes, were analyzed between the lower and higher diopter eyes. Correlations among binocular differences in spherical equivalent refraction, SFCT, and ETDRS grading scores were examined. Results: Lower diopter eyes had significantly lower ETDRS scores (35.3 ± 14.5 vs. 54.4 ± 21.3, P < 0.001) and thinner SFCT (153.0 ± 109.4 µ m vs. 235.6 ± 107.2 µ m, P < 0.001) compared with higher diopter eyes. Lower diopter eyes exhibited fewer cystoid spaces in the outer nuclear layer, reduced hyperreflective foci, less disorganization of retinal inner layers, and less disruption of the ellipsoid zone. Significant positive correlations were found between binocular differences in spherical equivalent refraction and ETDRS scores (ρ = 0.789, P < 0.001), SFCT and ETDRS scores (ρ = 0.726, P < 0.001), and spherical equivalent refraction and SFCT (ρ = 0.719, P < 0.001). Conclusion: Myopia seems to have a protective effect against diabetic retinopathy progression in anisometropia, as indicated by lower ETDRS scores and favorable optical coherence tomography biomarkers.