Background: A predominant and various microvascular outcome of diabetes mellitus (DM) is diabetic retinopathy (DR), which leads to loss of vision gradually and blindness if not treated early. Aim: Detecting retinal microvascular changes in diabetic cases can help detect early diabetic changes and manage them effectively, ultimately improving the quality of life for these patients. Patients and methods: This observational, analytical, cross-sectional research has been performed on ninety eyes, separated into three groups: Group I (DM no. DR): 30 eyes of diabetic cases that had no diabetic retinopathy; Group II (NPDR): 30 eyes of DM cases who had non-proliferative DR; and Group III (PDR): 30 eyes of diabetic cases that had proliferative diabetic retinopathy in the Outpatient Clinic in the Ophthalmology Department at Suez Canal University in Ismailia City. Results: The mean BCVA was significantly lesser among the more severe diabetic group, with statistically significant distinctions (p < 0.001). The average thickness of retina was significantly greater among the more severe diabetic group, with statistically significant differences. The measurement of vessel density demonstrated the most accurate ability to detect and categorize DR, with the best level of sensitivity for the two diagnosis and categorization and the greatest level of specificity in categorization of retinopathy. Conclusion: The optical coherence tomography-angiography information may be employed to evaluate the DR extent and to give early indications prior to fundus lesions happening within diabetic cases. The DR was worsened by the decline in vessel density in DCP and SCP.