Macular thickness changes across the spectrum of diabetic retinopathy: An optical coherence tomography based study

Background: Diabetic retinopathy is a major cause of visual impairment in patients with diabetes mellitus, with diabetic macular edema being the principal cause of vision loss. Optical Coherence Tomography (OCT) enables objective evaluation of macular structural changes and disease severity.

Aim: To assess changes in central and parafoveal macular thickness across different stages of diabetic retinopathy and their association with diabetic macular edema and glycemic control.

Methodology: This hospital-based observational study included 60 patients (92 eyes) with diabetic retinopathy. All patients underwent comprehensive ophthalmic evaluation and spectral-domain OCT. Central foveal thickness and ETDRS-based macular thickness parameters were analyzed across diabetic retinopathy severity grades. Eyes with Center-Involving Diabetic Macular Edema (CI-DME) were compared with those having Non–Center-Involving Diabetic Macular Edema (NCI-DME). The association between HbA1c levels and central foveal thickness was evaluated.

Results: Central foveal thickness increased significantly with worsening severity of diabetic retinopathy (p < 0.001), with highest values in proliferative disease. Inner ETDRS ring sectors showed progressive thickening across retinopathy stages. Eyes with CI-DME demonstrated significantly greater central and parafoveal macular thickness compared to NCI-DME. Higher HbA1c levels were associated with increased central foveal thickness.

Conclusion: Macular thickness increases progressively with advancing diabetic retinopathy, with greater involvement in center-involving macular edema. OCT is a valuable tool for assessing macular involvement and disease severity.

Keywords: Diabetic Retinopathy, Diabetic Macular Edema, Optical Coherence Tomography, Central Foveal Thickness, HbA1c.

Priyanka Yadav, a postgraduate resident in the Department of Ophthalmology at N.C. Medical College and Hospital, Haryana. She is actively involved in clinical ophthalmology, academic activities, and research work. Her areas of interest include retinal imaging, anterior segment disorders, and the application of imaging modalities in routine clinical practice. She regularly participates in academic presentations, conferences, and clinical discussions, and she aims to strengthen her clinical and research skills to contribute to evidence-based ophthalmic care.