Evaluation of vessel density in disorganization of retinal inner layers after resolved diabetic macular edema using optical coherence tomography angiography

Purpose: To evaluate the retinal vessel density (VD) in the macular region and the foveal avascular zone (FAZ) area using optical coherence tomography angiography (OCTA) in patients with and without disorganization of retinal inner layers (DRILs) after resolution of diabetic macular edema. Methods: Thirty-seven eyes of 37 DRIL patients (mean age 63 ± 13.97 years), 30 eyes of 30 no DRIL patients and 35 eyes of 35 controls were enrolled in this study. We evaluated the VD in the macular region of superficial capillary plexus (SCP), deep capillary plexus (DCP) and FAZ area. Results: DRIL and no DRIL groups showed decreased VD in SCP and DCP (p<0.05) and a larger FAZ area (p<0.001) compared to controls. However, DRIL patients revealed a statistically significant reduction in VD of SCP (p = 0.041) and a greater FAZ area (p<0.001) with respect to no DRIL patients. We found a significant negative correlation between the VD of the foveal SCP (r = -0.414, p = 0.011), foveal DCP (r = -0.358, p = 0.025) and best corrected visual acuity (BCVA) in DRIL group. Moreover there was a significant positive correlation between the FAZ area (r = 0.425, p = 0.034) and BCVA. Therefore, in presence of DRILs lower VD values of SCP and DCP and a larger FAZ area correlated with a worse visual acuity. In no DRILs group, there was a significant negative correlation between the VD of the foveal DCP and BCVA. Conclusion: OCTA highlights the role of retinal vascular ischemia in the pathogenesis of DRILs. This parameter could represent an important functional predictive factor in diabetic patients.