Best-corrected visual acuity (BCVA) is often the go-to measurement optometrists use when assessing a patient’s visual quality—but it’s not always the best one. Take, for instance, those with epiretinal membrane (ERM). This abnormal growth over the retina can warp vision in ways that may not be measurable using BCVA. The solution for many cases is surgical removal of the membrane, and treatment success cannot be measured using BCVA alone. Instead, researchers are saying that ERM peel improves a patient’s reading ability, even when the BCVA score remains unchanged.

The team of Japanese researchers conducted a prospective observational study that involved 42 eyes of 40 patients with idiopathic ERM. The investigators established a baseline of BCVA, reading ability and metamorphopsia score and reviewed the patients at three, six and 12 months after surgery. Reading ability was examined using the MNREAD-J, the Japanese version of the MNREAD reading acuity charts, to determine reading acuity, critical print size and maximum reading speed.

The subjects exhibited significantly improved BCVA, reading acuity and critical print size throughout the post-surgery examination period and significantly improved maximum reading speed at 12 months post-surgery. However, in 23 of the eyes, the BCVA change was only 0.1 logMAR, less than the 0.2 logMAR required to call it a significant change. In those same 23 eyes, the median BCVA did not change, but the median reading acuity and critical print size improved by 0.2 logMAR.

“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,” the study reads.

Mieno H, Kojima K, Yoneda K, et al. Evaluation of pre- and post-surgery reading ability in patients with epiretinal membrane: a prospective observational study. March 10, 2020. [Epub ahead of print].