Study of Imaging Biomarkers as a Prognostic Factor and Guide in the Management of Diabetic Macular Oedema

Background: Diabetic macular oedema (DME) is a major cause of vision impairment in individuals with diabetes mellitus, characterised by fluid accumulation in the macula due to increased vascular permeability. The growing prevalence of diabetes worldwide has led to an increasing burden of DME on healthcare systems. While current treatment options such as anti-vascular endothelial growth factor (anti-VEGF) injections, corticosteroids, and laser therapy exist, the variability in patient responses highlights the need for reliable prognostic tools. Imaging biomarkers, particularly those identified using optical coherence tomography (OCT) and fluorescein angiography (FA), play a critical role in diagnosing and managing DME. This study evaluates the prognostic significance of these biomarkers in predicting disease progression and treatment outcomes. Materials and methods: This prospective observational study was conducted at Gandhi Medical College and Hamidia Hospital, Bhopal, Madhya Pradesh, from August 2022 to June 2024. A total of 123 patients with Type II diabetes mellitus diagnosed with DME were included through consecutive sampling. Comprehensive assessments, including visual acuity, slit-lamp examination, fundus evaluation, FA, and OCT, were performed. Key imaging biomarkers, such as central subfield thickness (CST), disorganisation of retinal inner layers (DRIL), intraretinal cysts, hyperreflective foci, and vitreomacular interface (VMI) abnormalities, were evaluated. Correlations between biomarkers, best-corrected visual acuity (BCVA), metabolic markers (HbA1c, serum cholesterol), and disease severity were analysed using statistical tools, including the chi-square test and Pearson's correlation. Results: The most common biomarkers observed were DRIL with external limiting membrane (ELM) disruption (38, 31%), intraretinal cysts with ELM disruption (36, 29.3%), and hyperreflective foci (28, 22.8%). VMI abnormalities were noted in 14 (11.4%) cases, while subretinal fluid with serous retinal detachment was present in seven patients (5.7%). Significant negative correlations were found between BCVA (LogMAR) and biomarkers, with intraretinal cysts (-0.526, p=0.003) and VMI abnormalities (-0.492, P=0.002) having the strongest associations. Higher glycosylated haemoglobin (HbA1c) levels were significantly associated with intraretinal cysts (P=0.014) and VMI abnormalities (P=0.042), while higher cholesterol levels correlated with hyperreflective foci (P=0.011) and subretinal fluid (P=0.014). Patients with proliferative diabetic retinopathy (PDR) exhibited worse visual outcomes and greater CST compared to those with non-proliferative diabetic retinopathy (NPDR). Conclusion: Imaging biomarkers, particularly DRIL, intraretinal cysts, and VMI abnormalities, significantly correlate with visual acuity and metabolic control in DME patients. These findings underscore the importance of OCT in the prognostic assessment of DME and highlight the need for personalised treatment approaches based on biomarker profiles. Future studies should focus on long-term follow-up and explore the potential for integrating these biomarkers into clinical decision-making to improve patient outcomes.