Foveal vasculature changes and nonperfusion in patients with diabetes types I and II with no evidence of diabetic retinopathy

Purpose: To analyze the foveal avascular zone (FAZ) in patients with diabetes and no retinopathy vs. controls using OCT angiography (OCT-A). Methods: Prospective, observational clinical study. Type I and II diabetics with no retinopathy and healthy control patients underwent OCT-A. The FAZ size and capillary density were calculated using Image J and Adobe Photoshop CS8. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple comparison test and the Pearson correlation test. Results: Fifty-two eyes of 28 diabetic patients and 28 eyes of 16 healthy controls were enrolled. Type I diabetes patients had a longer disease duration than type II (30.3 ± 10.3 vs. 12.3 ± 9.7 years). The mean superficial capillary plexus (SCP) of the FAZ area was 0.27 ± 0.1, 0.36 ± 0.14, and 0.27 ± 0.12 mm², for the type I, type II, and controls (p = 0.0058) and was significantly larger in type II diabetics (p < 0.05). The mean DCP (deep capillary plexus) FAZ was significantly larger in type II diabetics vs. controls (0.67 ± 0.2 and 0.52 ± 0.16 mm² respectively) (p < 0.05). Both type I and type II SCP capillary density were significantly lower than the controls (p < 0.05, p < 0.005), and DCP capillary density was significantly lower in type II vs. controls (p < 0.005). Conclusions: Type I patients showed fewer changes in the FAZ than the type II group, although their duration of diabetes was longer. Larger studies are needed to better analyze the differences between type I and type II diabetics.