Predictors of the presence of cystoid macular edema after idiopathic epiretinal membrane surgery

Aim
To determine the predictors of the presence of cystoid macular edema (CME) after idiopathic epiretinal membrane surgery.

Material and methods
A two-center retrospective cohort study. A review of consecutive patients with ERM who underwent pars plana vitrectomy with ERM peeling. The study involved an analysis of a set of factors at baseline and during one-year follow-up, including best-corrected visual acuity (BCVA, LogMAR) and optical coherence tomography markers, surgical factors (posterior capsulotomy, steroid use, type of tamponade, ILM peeling). The statistical model utilized uni- and multivariate logistic regression analyses with final CME presence as a binary outcome.

Results
One-hundred twenty eight eyes (125 patients) were enrolled in the study. A significant improvement in BCVA was noted in both groups, but the improvement rate was faster in the non-CME group. Univariate analysis showed that young age (OR 0.9, CI 0.84-0.96, p = 0.02), air tamponade (OR 8.62, CI 1.92-38.73, p = 0.005), and silicone oil tamponade (OR 2.31, CI 1.02-51.69, p = 0.048) represented risk factors for the presence of CME after PPV. Conversely, intraoperative posterior capsulotomy and intravitreal steroid administration were not associated with the incidence of CME. The risk factors for new postoperative CME included air tamponade (OR 3.80, CI 1.62-8.92, p = 0.002) and increased preoperative central retinal thickness (OR 1.01, CI 1.00-1.01, p = 0.011). However, in the multivariate analysis none of the evaluated parameters was found to be statistically significant.

Conclusions
The presence of cystoid macular edema is a negative prognostic factor after PPV in ERM patients. There is no link between an increased incidence of CME and the stage of ERM or intraoperative factors such as posterior capsulotomy, intraoperative steroid administration, ILM peeling, or the type of tamponade.