Prognostic factors of idiopathic epiretinal membrane surgery and evolution of alterations of the central cone bouquet.

Purpose: To describe the structural changes observed postoperatively in epiretinal membranes (ERM), in particular the alterations in the central cone bouquet (CB), and to identify prognostic factors that might predict postoperative outcome.

Methods: We included 125 eyes of 117 patients who underwent idiopathic ERM removal with at least a 6-month follow-up. For each patient, spectral-domain optical coherence tomography (SD-OCT) was performed and best-corrected visual acuity (BCVA) was measured, before and after surgery.

Results: Before surgery, 44 eyes (35.2%) presented CB alterations: 65.9% a cotton ball sign, 15.9% a foveolar detachment and 18.2% a pseudovitelliform lesion. Median BCVA increased from 20/63 to 20/32 post-operatively (p = .001) with a mean follow-up of 17 months. The disappearance of CB alterations after surgery was observed in 97.7% of eyes. In stage 3 and 4 ERM, ectopic inner foveal layers persisted in 76.7% of eyes after surgery. Postoperative BCVA was correlated with change in central macular thickness and initial BCVA and was not correlated with the presence of preoperative CB alteration, the initial stage of ERM, the presence of postoperative dissociated optical nerve fiber layer, and the disappearance of ectopic inner fiber layers. The combination of cataract surgery and capsulotomy did not seem to change visual outcome and seemed to accelerate visual recovery. Incidentally, general anesthesia was correlated with final BCVA.

Conclusion: ERM surgery allowed a significant gain in BCVA and the disappearance of CB alterations in the great majority of cases. CB alteration did not show to be associated with poor visual prognosis.