Correlation of Optical Coherence Tomography Biomarkers with Visual Outcomes in Patients with Diabetic Macular Edema: A Prospective Longitudinal Study

Abstract

Background: Diabetic macular edema (DME) is one of the major causes of visual impairment among diabetic patients worldwide. Optical coherence tomography (OCT) plays an important role in identifying retinal structural changes and biomarkers associated with disease severity and visual prognosis.
Aim: To evaluate the correlation between OCT biomarkers and visual outcomes in patients with diabetic macular edema.
Materials and Methods: This prospective longitudinal study was conducted in the Department of Ophthalmology, Darbhanga Medical College and Hospital, Laheriasarai, Darbhanga, Bihar, India, from July 2024 to June 2025. A total of 100 patients with diabetic macular edema were included. Detailed ophthalmic examination, best corrected visual acuity (BCVA), fundus examination, and spectral-domain OCT imaging were performed. OCT biomarkers including central macular thickness (CMT), disorganization of retinal inner layers (DRIL), hyperreflective foci (HRF), subretinal fluid (SRF), ellipsoid zone disruption (EZD), and intraretinal cysts (IRC) were evaluated. Statistical analysis was performed using SPSS version 26.0. Pearson correlation coefficient, paired t-test, ANOVA, and multivariate regression analysis were used. p<0.05 was considered statistically significant.
Results :The mean age of study participants was 58.6 ± 8.7 years. Significant improvement in visual acuity was observed during follow-up, with mean BCVA improving from 0.82 ± 0.24 logMAR at baseline to 0.51 ± 0.19 logMAR at 12 months (p<0.001). Mean central macular thickness decreased significantly from 468.4 ± 92.5 μm to 311.2 ± 58.6 μm (p<0.001). DRIL, ellipsoid zone disruption, and hyperreflective foci demonstrated significant negative correlation with final visual acuity (p<0.001). Multivariate regression analysis identified DRIL and ellipsoid zone disruption as independent predictors of poor visual outcome.
Conclusion: OCT biomarkers show strong correlation with visual outcomes in diabetic macular edema. DRIL, ellipsoid zone disruption, and hyperreflective foci were associated with poorer visual prognosis. OCT biomarker evaluation may help in prognostication and individualized management of DME.