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Updated: Mar 20, 2026
Measuring the Behavioral Effects of Intraocular Scatter
Published on: February 18, 2021
The effect of luminance on visual acuity measurement in eyes with epiretinal membrane
Yui Nariai1, Masayuki Horiguchi2, Tadashi Mizuguchi1
1Department of Ophthalmology, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-Cho, Toyoake City, Aichi prefecture, 470-1192, Japan.
Purpose:
Visual acuity (VA) assessment is crucial for evaluating visual function, but inter-clinic VA measurement variations were observed in patients with epiretinal membrane (ERM). Inter-clinic variations in acuity chart luminance exist because the International Organization for Standardization (ISO) recommends a range of 80-320 cd/m2 for VA charts. We investigated the effects of luminance within this ISO range on the VA in patients with ERM.
Study Design:
Prospective observational study.
Methods:
We analyzed data from 187 patients with ERM and a normal fellow eye with a decimal VA of ≥1.0 at 320 cd/m2 OU. Baseline VA was measured at 320 cd/m2, then reduced in 0.1-log unit steps using neutral density filters. Metamorphopsia was evaluated with the Amsler Grid Test. The luminance causing a two-line VA reduction from 320 cd/m2 was measured before and after ERM removal.
Results:
In normal fellow eyes, a two-line VA reduction occurred at approximately 40 cd/m2, indicating stable VA within the normal ISO range, while in affected eyes, it happened at around 150 cd/m2. The luminance difference causing a two-line VA reduction between eyes with and without metamorphopsia was not significant. For surgical patients, the luminance causing a two-line VA reduction decreased over time: from 153 cd/m2 preoperatively to 36 cd/m2 at 6 months postoperatively.
Conclusions:
Considering the luminance is critical when measuring VA in patients with ERM.
