Multifocal Electroretinogram Changes in Diabetic Patients without Clinical Retinopathy

Background: In the working-age population, diabetic retinopathy (DR) is the most common cause of blindness, and diabetes mellitus (DM) is a global epidemic that continues to cause significant morbidity and mortality. The prevalence of DR has been on the rise. Worldwide, some 486 million people have diabetes, with about a third showing signs of diabetic retinopathy, according to recent estimates. Aim: To assess the impact of multifocal electroretinogram (mfERG) on retinal electrophysiology in diabetic patients who do not yet have retinopathy; this will allow for the early detection of aberrant retinal changes in people with type 2 diabetes who do not yet have visible diabetic retinopathy. Subjects and methods: The ophthalmology department of Al-Azhar University Hospitals in Cairo, Egypt, carried out this observational comparison study from September 2024 to July 2025. Group I consisted of 30 diabetic patients who did not have retinopathy, and Group II consisted of 30 healthy controls. Results: A statistically significant decrease in amplitude of P1 in group-I patients when compared with group-II patients in all rings (p-value<0.001). Statistically significant increase in implicit time (IT) in ring 1 (p-value=0.005), statistically significant increase in IT in ring 4 and 5 (p-value<0.001), and no statistically significant difference in IT in ring 2 and ring 3 between group-I and group-II. Highly statistically significant (p-value<0.001) increased foveal avascular zone (FAZ) in group-I patients (mean=0.34±0.05, range=0.25- 0.48) when compared with group-II patients (mean=0.28±0.02, range=0.26- 0.33). Conclusion: The multifocal electroretinogram and optical coherence tomography angiography (OCTA) can detect early diabetic changes in the retina without apparent DR.