Semiautomatic analysis of retinal ischemia using widefield OCTA in patients with diabetes mellitus with or without diabetic retinopathy

Abstract

Purpose

This study assessed retinal non-perfusion areas (RNPAs) and vascular density (VD) in the superficial (SCP) and deep (DCP) capillary plexuses of diabetic patients across three stages of diabetic retinopathy (DR): no DR (stage 0), non-proliferative DR (stage 1), and proliferative DR (stage 2).

Methods

Thirty-nine right eyes of 39 diabetic patients were included and underwent 3 × 3 mm and 15 × 15 mm Optical Coherence Tomography Angiography (OCTA) scans. A semiautomated software was utilized to quantify RNPAs and VD. Correlations with systemic and ocular factors were analyzed.

Results

Six eyes were in stage 0, 25 eyes were in stage 1 and 8 eyes were in stage 2. Mean RNPAs and VD from 15 × 15 mm OCTA scans differed significantly across the three DR stages. A positive correlation was found between DR stage and RNPA in both SCP (CC = 0.42; p = 0.04) and DCP (CC = 0.60; p = 0.004). Conversely, VD in DCP was negatively correlated with DR severity (CC = −0.51; p = 0.0018). Eyes with prior peripheral laser treatment showed significantly larger RNPAs and lower VD in wide-field scans. Macular edema was associated with increased RNPA and reduced VD in the SCP on 3 × 3 mm OCTA (p's < 0.001). No significant associations were observed between OCTA parameters and systemic factors (e.g., hypertension, nephropathy).

Conclusion

Semiautomated OCTA analysis of retinal ischemia correlates positively with DR stage, peripheral laser treatment, and macular edema. The lack of association with systemic factors highlights the critical role of local ocular changes in DR progression.