Retinal Microvascular Changes of Subclinical Diabetic Retinopathy Using Optical Coherence Tomography Angiography

Abstract

Background: Patients with subclinical diabetic retinopathy (DR) are those who are diagnosed with diabetes mellitus (DM) with a duration of 4–8 years, with no frank manifestations of DR, neither on clinical examination nor by the common diagnostic tools. This study aimed to evaluate retinal and choriocapillary parameters in subclinical diabetic patients using optical coherence tomography angiography (OCTA). Methods: This was a cross-sectional observational study that included a total of 145 eyes. The patients were divided into two groups: The eyes were categorized into two groups: Group A: That included 105 eyes with diabetes (Cases group). Group B: That included 40 eyes of healthy individuals (Control group). Results: FAZ area in SCP was significantly higher in the case group compared to the control group. There was an insignificant correlation between disease duration and FAZ area in SCP, between disease duration and Superficial density and between disease duration and macular thickness. There was a negative significant correlation between disease duration and the whole region (r=- 0.312, P=0.001). Conclusion: OCTA provides a non-invasive objective tool with depth-resolved imaging that enables detailed enface visualization of the superficial and deep retinal vasculature. The subclinical diabetic retinopathy was associated with decrease in superficial capillary density, deep capillary density and increase in the macular thickness as compared to the healthy eyes. However, the limitations of OCTA to scan peripheral retinal vascular changes still can’t eliminate the role of FFA in the diagnosis and follow-up of retinal vein occlusion.