PREVALENCE AND RISK FACTORS OF ELLIPSOID ZONE DAMAGE AFTER PARS PLANA VITRECTOMY FOR IDIOPATHIC EPIRETINAL MEMBRANE

Purpose: To assess factors associated with external limiting membrane (ELM)/ellipsoid zone (EZ) damage after pars plana vitrectomy (PPV) for epiretinal membrane and evaluate ELM/EZ damage impact on functional and anatomical outcomes. Methods: Patients who underwent PPV with epiretinal membrane +/- inner limiting membrane peeling were retrospectively analyzed. Best-corrected visual acuity and central macular thickness were longitudinally collected based on the available follow-up. Demographic data, clinical data, and surgical details were included in logistic regression models having ELM/EZ damage as a binary outcome. Results: Overall, 179 eyes (171 patients) were included; 93 had a 12-month follow-up. Thirty-four eyes (19%) had ELM/EZ damage after surgery; in nine eyes (5%), ELM/EZ damage persisted at 12 months. Phacoemulsification during PPV (odds ratio = 6.97; P = 0.007) and ELM/EZ damage before PPV (odds ratio = 6.91; P = 0.007) were risk factors for postoperative ELM/EZ disruption. Thicker outer nuclear layer (P = 0.002), thicker ectopic inner foveal layer (P < 0.001), and higher endoillumination power (P = 0.03) were associated with slower visual recovery. Inner limiting membrane peeling (P = 0.04) was associated with slower anatomical recovery. Conclusion: Cataract extraction and outer retinal damage before PPV are associated with higher risk of photoreceptor damage postoperatively. The rate of visual improvement varies as a function of retinal layers' distortion before surgery; additional retinal manipulation slows restoration of the macular anatomy.