Evaluation of retinal layers following pars plana vitrectomy in idiopathic and diabetic epiretinal membrane.
CLINICAL RELEVANCE Optical coherence tomography can enhance preoperative evaluation in patients with epiretinal membranes, improve surgical planning, and provide patients with more detailed information about potential visual outcomes. BACKGROUND Investigate the morphological and functional changes in idiopathic and diabetic epiretinal membrane. METHODS All participants underwent optical coherence tomography preoperatively and 6 months postoperatively. Foveal contour, retinal segmentation, external limiting membrane and ellipsoid zone integrity, subfoveal fluid, disorganisation of inner retinal layers, and ectopic inner foveal layer were evaluated with optical coherence tomography. Associations between optical coherence tomography parameters and visual acuity were analysed. RESULTS This study included 34 idiopathic epiretinal membrane and 31 diabetic epiretinal membrane cases. In the idiopathic epiretinal membrane group, preoperative foveal pit presence was associated with better visual acuity (p = 0.030). In the diabetic epiretinal membrane group, the preoperative subfoveal fluid, disorganisation of inner retinal layers, ectopic inner foveal layer, cystic changes and advanced stage were associated with lower preoperative visual acuity (p = 0.008; p = 0.001; p = 0.021; p = 0.043; p = 0.01; respectively). In the postoperative period the persistence of subfoveal fluid, ectopic inner foveal layer and advanced stage were associated with lower postoperative visual acuity in the diabetic epiretinal membrane group (p = 0.002; p = 0.016; p = 0.018, respectively). external limiting membrane integrity was better preserved preoperatively in the idiopathic epiretinal membrane group (p = 0.022). Ellipsoid zone integrity was better preserved in the idiopathic epiretinal membrane group compared to the diabetic epiretinal membrane group, both preoperative and postoperative period (p = 0.010 and p = 0.022, respectively). In multivariable linear regression analysis, the presence of preoperative subfoveal fluid was independently associated with poorer postoperative visual acuity. The inner retinal layers were significantly thinned in both groups, while the outer layers remained unchanged. CONCLUSION Although most retinal segmentation parameters showed similar postoperative changes in both idiopathic epiretinal membrane and diabetic epiretinal membrane, diabetic epiretinal membrane eyes demonstrated greater impairment of outer retinal biomarkers. Preoperative subfoveal fluid may be associated with postoperative visual outcomes in diabetic epiretinal membrane and warrants further investigation in larger prospective studies. Vitrectomy yielded beneficial anatomical and functional results in both groups.