Associated factors and surgical outcomes of microcystoid macular edema and cone bouquet abnormalities in eyes with epiretinal membrane

Purpose:To investigate the associated features and the surgical outcomes in eyes with microcystoid macular edema (MME) and cone bouquet abnormalities (CBA) undergoing epiretinal membrane peeling.Methods:Retrospective study including patients who underwent pars plana vitrectomy for idiopathic epiretinal membrane. Factors associated with MME and CBA at baseline and their regression were identified with logistic regression models. Postoperative visual acuity was evaluated with linear mixed models from baseline to 12 months. Risk factors for new or worsened macular edema were explored with a Cox regression model.Results:One hundred and eighty-seven eyes are included in this study; 30 eyes (16%) had MME and 53 eyes (28%) had CBA preoperatively. Microcystoid macular edema was associated with severe epiretinal membrane stage (odds ratio [95% confidence interval] = 3.6 [1.3-12.7], P = 0.02); CBA was inversely associated with ectopic inner foveal layer thickness (odds ratio [95% confidence interval] = 0.97 [0.97-0.99] for each 1-m EIFL increase, P = 0.006). Eyes with MME had worse visual acuity after epiretinal membrane peeling (P = 0.01) and were at risk of macular edema worsening (hazard ratio [95% confidence interval] = 2.22 [1.01-5.16], P = 0.04). Older age was associated with MME persistence (odds ratio [95% confidence interval] = 2.46 [1.06-6.82] for each 10-year increase, P = 0.04). No significant associations were found for CBA.Conclusion:Although CBA had no prognostic consequences, MME was associated with suboptimal visual recovery and less efficient control of inflammation after surgery. Degeneration of Müller cells may have an alleged role, and further imaging and functional tests are warranted.