Changes in Visual Acuity after Idiopathic Epiretinal Membrane Removal: Good versus Poor Preoperative Visual Acuity.

Purpose: To investigate postoperative visual acuity changes following idiopathic epiretinal membrane (ERM) surgery as well as investigate the relationship between outcome and baseline visual acuity.

Methods: The medical records of 159 consecutive eyes were retrospectively reviewed for best corrected visual acuity (BCVA), central subfield macular thickness (CSMT), and the ellipsoid zone (EZ) signal of the photoreceptor layer at baseline and 1, 3, and 6 months after surgery. Patients were divided into two groups: group A, with good vision of 20/50 or better, and group B, with poor visual acuity worse than 20/50.

Results: Seventy-nine eyes were included in group A and 80 eyes in group B. Mean baseline BCVA was 0.28 and 0.65 logarithm of the minimum angle of resolution (logMAR), and the mean baseline CSMT was 423.7 and 505.6 μm in group A and group B, respectively. In group A, BCVA worsened to 0.39 logMAR at 1 month (p < 0.001) and gradually improved to 0.25 logMAR at 6 months, which was not different from baseline BCVA. In group B, BCVA and CSMT improved at 1, 3, and 6 months (p < 0.05). The EZ signal improved in group B (p = 0.003) but not in group A. The area under the receiver operating characteristic curve for the improvement in BCVA of ≥ 2 lines was significant for preoperative BCVA (0.717, 95% confidence interval 0.638-0.797; p < 0.001). The cutoff value was 0.35 on the logMAR scale.

Conclusion: After ERM surgery, patients with good vision maintained visual acuity after temporary worsening of vision, and patients with poor vision achieved significant BCVA improvement.