Evaluation of Microvascular Changes in the Perifoveal Vascular Network Using Optical Coherence Tomography Angiography (OCT-A) in Type I Diabetes Mellitus

Diabetic retinopathy (DR) is the leading cause of blindness in type 1 Diabetes Mellitus (DM) patients, as a consequence of impaired blood flow in the retina. Optical coherence tomography angiography (OCT-A) is a newly developed, non-invasive, retinal imaging technique that allows detection of perfused and non perfused areas of the retina without the injection of dye. This OCT-based method permits adequate delineation of the perifoveal vascular network, and allows objective identification of microvascular changes, such as capillary dilation or presence of microaneurisms. It is also capable to detect paramacular areas of capillary non perfusion and/or enlargement of the foveal avascular zone (FAZ), representing an excellent tool for assessment of diabetic retinopathy.

Given that all these features are commonly seen in diabetic patients, the relationship of these microvascular changes with systemic factors such as metabolic control or duration of the disease still need to be elucidated. Interestingly, further studies are required to investigate whether these changes reflect those occurring elsewhere in the body affected by diabetic microvascular disease, as the kidneys or the brain. If these relationships were demonstrated, early detection of these microvascular changes could lead to modifications in the pharmacological management of diabetic patients, as a way to reduce the risk of future complications in both the eye and other organs. The aim of this study is to evaluate the role of OCT-A in the evaluation of the perifoveal vascular network in type 1 diabetic patients, and to investigate the relationship between these OCT-A-derived parameters and demographic and clinical factors, as metabolic control and duration of the disease.