Long-Term Visual Acuity and Optical Coherence Tomography Changes After Vitrectomy for Idiopathic Epiretinal Membranes

Objective: To evaluate the long-term visual acuity and retinal thickness changes after pars plana vitrectomy (PPV) for idiopathic epiretinal membranes (ERM).Methods: We performed a retrospective analysis of 72 patients who underwent PPV for idiopathic ERM in a tertiary hospital over 5 consecutive years. The main outcome measurement was change in visual acuity and macular thickness as recorded with optical coherence tomography (OCT).Results: Medical records of 239 patients with a diagnosis of ERM who underwent PPV with or without internal limiting membrane (ILM) peeling were reviewed; of these, 72 patients with idiopathic ERM were included in the final analysis. All patients completed at least one year of follow-up, and 23 patients (30%) had 5 or more years of follow-up. The mean preoperative best corrected visual acuity (BCVA) was 20/65, and mean preoperative central macular thickness (CMT) on OCT was 434 microns (mu m). Mean post-operative BCVA and CMT at one year were 20/40 and 303 mu m, respectively (p<0.0001). A total of 42 patients (58%) improved by 2 or more lines; BCVA and CMT continued to improve postoperatively for up to 5 years of the follow-up period. There was no significant difference in BCVA or CMT between phakic and pseudophakic patients, and ILM peeling was performed in 67% of patients. Improved BCVA at 1 year was associated with younger age (p<0.0001) and ILM peeling (p=0.020). Conclusion: PPV is an effective treatment for idiopathic ERM, and ILM peel may be of benefit. BCVA continues to improve up to 2 years and beyond after surgery regardless of the duration of symptoms.