Early microvascular changes in patients with prediabetes evaluated by optical coherence tomography angiography

Background: Timely detection of early microvascular changes in patients with prediabetes could help reduce the likelihood of progression of diabetes-related retinal complications. Aim: To determine early microvascular changes in patients with prediabetes using optical coherence tomography angiography (OCT-A). Methods: In this single-center retrospective case-control study, macular OCT-A images of superficial capillary plexus (SCP) and deep capillary plexus (DCP) were analyzed in non-diabetic controls, and prediabetic and diabetic subjects. A quantitative analysis was performed using ImageJ software of the foveal avascular zone (FAZ) area, acircularity index (AI), perfusion density (PD), and vascular length density (VLD). Results: A total of 94 eyes of 53 patients were included in this study. The global mean age was 57.7 years, 39.6% men and 60.4% women. In SCP, the mean PD was 0.283 +/- 0.15, 0.186 +/- 0.720, and 0.186 +/- 0.07 in non-diabetic controls, and prediabetic and diabetic groups, respectively. The mean VLD was 8.728 +/- 3.425 in non-diabetic controls, 6.147 +/- 1.399 in prediabetic group, and 6.292 +/- 1.997 in patients with diabetes. The comparison of prediabetic patients and controls shows statistical differences between PD and VLD in both plexus SCP (p = 0.002 and p = 0.001, respectively) and DCP (p = 0.005 and p = 0.002, respectively). The mean area of FAZ in patients with diabetes and normal individuals was 0.281 and 0.196 mm(2), respectively (p < 0.001). AI was higher in the control group (0.87 +/- 0.14) and prediabetic group (0.80 +/- 0.17) compared to diabetic patients (0.64 +/- 0.19). There were no differences in FAZ area and AI between prediabetic and non-diabetic controls. Conclusion: PD and VLD demonstrated to be early microvascular changes in prediabetic patients evaluated by OCT-A. No alterations of FAZ were evidenced in this group.