Preoperative factors predictive of postoperative decimal visual acuity ≥ 1.0 following surgical treatment for idiopathic epiretinal membrane

PURPOSE To report the preoperative best-corrected visual acuity (BCVA) and foveal thickness (FT) values that lead to a postoperative decimal BCVA of ≥1.0 after surgical removal of an idiopathic epiretinal membrane (ERM). METHODS This is a retrospective case series of 73 eyes that underwent surgery for removal of an idiopathic ERM. All eyes had been treated by a single surgeon using a 25-gauge transconjunctival sutureless vitrectomy and indocyanine green-assisted internal limiting membrane peel. The BCVA and FT were measured at baseline and 6 months postoperatively. RESULTS A postoperative decimal BCVA ≥ 1.0 was obtained in eyes with a preoperative decimal BCVA ≥ 0.3 but not in those with a preoperative decimal BCVA ≤ 0.2. The incidence of obtaining a postoperative decimal BCVA ≥ 1.0 was significantly (P = 0.002) higher in eyes with a preoperative decimal BCVA ≥ 0.5 (50%) than in eyes with a preoperative decimal BCVA < 0.5 (11%). Additionally, a postoperative decimal BCVA of ≥ 1.0 was obtained in 51% of the eyes that had a preoperative FT < 400 μm, compared with only 21% of eyes with a preoperative FT ≥ 400 μm (P = 0.01). The incidence of obtaining a postoperative decimal BCVA ≥ 1.0 was significantly higher in eyes with preoperative decimal BCVA ≥ 0.5 and FT < 400 μm (60%) than in eyes with preoperative decimal BCVA ≥ 0.5 and FT ≥ 400 μm (20%; P = 0.03) or preoperative BCVA < 0.5 and FT ≥ 400 μm (7%; P < 0.001). CONCLUSIONS These findings indicate that eyes with both preoperative BCVA ≥ 0.5 and FT < 400 μm have a significantly better chance of obtaining a postoperative decimal BCVA ≥ 1.0 following idiopathic ERM removal.