Impact of Vitreomacular Interface Status on Macular Microcirculation in DME

Purpose To investigate the impact of precisely stratified vitreomacular interface (VMI) status on macular microstructure and layer-specific microcirculation in eyes with diabetic macular edema (DME) using multimodal optical coherence tomography (OCT). Methods A total of 149 eyes from 149 consecutive patients with center-involved DME were classified into three groups based on standardized spectral-domain OCT: complete posterior vitreous detachment (PVD, n = 39), vitreomacular adhesion (VMA, n = 78), and vitreomacular traction (VMT, n = 32). All patients underwent structural OCT and OCT angiography (OCTA) imaging. Parameters including central subfield thickness (CST), ellipsoid zone (EZ) integrity, cyst morphology, and vessel density (VD) in the superficial (SCP) and deep capillary plexus (DCP) were analyzed and compared among groups. Results Eyes in the VMT group exhibited the worst anatomical and functional profiles, including significantly greater CST, higher EZ disruption scores, and a greater proportion of cystoid macular edema compared to the PVD and VMA groups (all P  < 0.05). OCTA analysis revealed a specific and significant reduction in DCP-VD in the VMT group compared to both the PVD and VMA groups (both P  < 0.001), while no significant differences were observed in SCP-VD among the three groups. Within the VMT group, traction height showed a strong negative correlation with DCP-VD ( r = -0.652, P  < 0.001) and a strong positive correlation with CST ( r  = 0.703, P  < 0.001). Multiple regression analysis confirmed that VMT status and lower DCP-VD were independent predictors of increased CST. Conclusions VMT represents a distinct DME phenotype characterized by significant deep capillary plexus ischemia, which correlates quantitatively with the degree of vitreous traction and is associated with more severe edema and structural disruption. These findings highlight a potential “traction-ischemia” mechanism in VMT-associated DME and support the integration of VMI assessment and OCTA-based microcirculation evaluation in the clinical management of DME.