Evaluation of pre- and post-surgery reading ability in patients with epiretinal membrane: a prospective observational study

Abstract

Abstract Background This study aimed to investigate the pre- and post-surgery reading ability in patients with idiopathic epiretinal membrane (ERM) to evaluate whether measurement of reading performance is a helpful test in addition to visual acuity (VA) as an assessment measure. Methods This prospective observational study involved 42 eyes of 40 patients with idiopathic ERM. Best-corrected visual acuity (BCVA), reading ability, and metamorphopsia score were evaluated at baseline and at 3, 6, and 12 months post-surgery. As the outcome measure, the reading ability of each patient (i.e., overall performance) was examined with MNREAD-J, the Japanese version of the MNREAD reading acuity (RA) charts, to determine RA, critical print size (CPS), and maximum reading speed (MRS). Generally, a difference of 0.2 logMAR or more is considered a significant change in BCVA. Thus, as a subgroup analysis, we additionally evaluated the BCVA and reading ability of the patients with a BCVA difference of 0.1 logMAR or less between at baseline and at 12 months post-surgery. Results Relative to their values at baseline, the subjects exhibited significantly improved BCVA, RA, and CPS throughout the post-surgery examination period (P < 0.001) and significantly improved MRS at 12 months post-surgery (P = 0.04). No significant change in the vertical metamorphopsia score was observed throughout the post-surgery follow-up period. However, and compared to the value at baseline, significant improvements in the horizontal metamorphopsia score were observed at 3, 6 (P < 0.05), and 12 months (P < 0.001) post-surgery. In the subgroup analysis of the 23 eyes that exhibited a BCVA improvement of 0.1 logMAR or less, the median BCVA did not change, but the median RA and CPS improved by 0.2 logMAR. Conclusions Our findings showed that the surgical removal of ERM improves reading ability, even when the BCVA score does not improve. The measurement of reading performance appears to be a helpful test in addition to VA as a measure for assessing the surgical removal of ERM.