Optical coherence tomography angiography as a prediction tool for diabetic retinopathy

• Main Author: Soha M.M Eltohamy
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2021-01-01
• Series: Delta Journal of Ophthalmology
• Subjects: diabetic retinopathy; foveal avascular zone; optical coherence tomography angiography; vessel density
• Online Access: http://www.djo.eg.net/article.asp?issn=1110-9173;year=2021;volume=22;issue=3;spage=214;epage=221;aulast=Eltohamy
• ISSN: 1110-9173; 2090-4835

Background Diabetic retinopathy (DR) represents the leading cause of blindness in working-age people. It affects about one in every three diabetic patients. This visual loss can be prevented by early detection and proper management. Purpose The aim of this study was to assess the ability of optical coherence tomography angiography (OCTA) to detect subclinical changes in parafoveal capillaries in diabetic patients without DR. Patients and methods This prospective case–control study was conducted upon 50 participants who were divided into two groups: group A (25 diabetic patients without clinical manifestation of DR) and group B (25 healthy control participants of matched age and sex with group A). The two groups were compared regarding the parameters of the foveal avascular zone (FAZ) area, perimeter, and FD (flow density of retinal capillaries within 300 µm surrounding the FAZ) in addition to the parafoveal vessel density of superficial and deep capillary plexuses (SCP and DCP) on macular scans (3×3 mm) centered on the fovea by OCTA. Results There were statistically significant differences in FAZ area, perimeter, and FD together with parafoveal vessel density of SCP and DCP between healthy controls and diabetic patients without DR. The mean FAZ area of the healthy control group B was 0.27±0.08 mm2 compared with 0.32±0.11 mm2 in the diabetic group A (P=0.01). In addition, the FAZ perimeter was significantly increased (P=0.003) in the diabetic patients without DR (2.39±0.56 mm) compared with the control (2.11±31 mm). Statistically significant decreases of vessel density in the FD-300, SCP, and DCP were observed in diabetic patients without DR compared with controls (all P<0.001). Regarding the FD-300, the mean value in the control group was 49.98±2.67%, whereas in the diabetic group it was 48.11±0.58%. The mean VD of the SCP in the healthy control group B was 47.62±2.58% compared with 44.32±3.01% in the diabetic group. The mean VD of the DCP in the healthy control group B was 56.13±2.23% versus 50.21±2.56% in the diabetic group. Conclusion OCTA is an effective tool in the early detection of microvascular changes of diabetic patients with no clinical manifestations of DR. Vessel density and FAZ metrics were proven to be early biomarkers for DR before becoming clinically evident.