Differences in macular thickness associated with peripheral retinal vessel whitening in diabetic patients

This study aimed to determine the difference in macular thickness among patients with diabetes mellitus (DM) with and without peripheral retinal vessel whitening (PRVW). PRVW was defined by retinal vessel whitening outside the standard seven ETDRS fields. Subjects were divided into DM with PRVW, DM without PRVW, and normal age-matched controls. Optical coherence tomography scans were divided into total, inner, and outer retinal layer thicknesses and were compared in the macula's central, inner, and outer rings. Forty-seven eyes were included: DM with PRVW = 15, DM without PRVW = 16, and Controls = 16. Overall, the mean retinal thickness in patients with DM with PRVW was lower than in patients with DM without PRVW and controls. In the inner macula, DM patients with PRVW showed a significantly lower mean inner superior, nasal, inferior, and temporal macula compared to DM patients without PRVW (p = 0.014, 0.008, 0.005, < 0.001, respectively). DM patients with PRVW also showed a significantly lower mean outer superior, nasal, inferior, and temporal macula than controls (p = 0.005, 0.005, 0.016, 0.025, respectively). This study demonstrates that PRVW in DM patients may be associated with global structural changes to the macular region, promoting a decrease in inner and outer retinal thickness. Further studies should investigate the functional correlation with PRVW in DM patients in order to better understand its potential implications in diabetic patients.