Optical Coherence Tomography Angiography Study for Evaluation of Microvascular Changes in the Subclinical Diabetic Retinopathy

Background: diabetic retinopathy is the specific microvascular complication of diabetes mellitus and affects 1 of 3 with DM. DR remains a leading cause of vision loss in working adult population. Patients with severe levels of DR were reported to have poor quality of life and reduced physical, emotional and social well-being, and they utilize more health care resources. Objective: this study aimed to evaluate the vascular density, perfusion density and foveal avascular parameters changes in subjects with diabetes mellitus showing no manifestations of diabetic retinopathy using optical coherence tomography angiography. Methods: 40 subjects were categorized into two groups, group A for healthy subjects and group B for the diabetic subjects. HbA1c, renal functions, liver functions and lipid profile were obtained from each individual. Best corrected visual acuity were obtained from each individual and each were subjected to full ophthalmic examination, IOP measurement, fundus fluorescein angiography FFA, Optical Coherence Tomography OCT and Optical Coherence Tomography Angiography OCTA. Results: statisticallysignificantdifferenceswerefoundbetweenthehealthygroupand the diabeticgroupin OCTA parameters. Full vascular density VD significantly decreases in the diabetic patients even in those showed BCVA ≥ 0.7 and totally intact FFA and OCT (P>0.001). Perfusion density PD also was significantly decreased in the diabetic patients (P>0.001). Foveal avascular zone showed significant changes in area value and perimeter, however the circularity changes were statisticallyinsignificant.Conclusion: using OCTA was proven to be clinically significant in differentiating healthy eyes from diabetic eyes that showed no clinically acceptable hallmarks. So, that the term “Subclinical diabetic retinopathy” was suggestible to refer to a clinical state where the FAZ metrics, vascular density and perfusion density showed a particular deviation from the normal healthy parameters.