Abstract
BACKGROUND: Fixed time extensions for visually impaired examinees ignore the wide variability in visual-acuity (VA) and visual-field (VF) deficits. Such one-size-fits-all policies may compromise fairness in high-stakes testing. METHODS: Thirty healthy adults (20–40 y) completed two exam-like tasks—oral reading and word search—under ten simulated visual conditions. VA was degraded to decimal 0.4 (logMAR 0.40; ≈20/50) or decimal 0.1 (logMAR 1.00; ≈20/200) using plus-lens fogging at 40 cm; a 0.9-mm pinhole (PH) imposed an approximately 10–15° concentric VF restriction. Font size were normal or enlarged. Each participant served as their own control; the baseline testing condition was decimal VA 1.0, no pinhole, normal font size. Task completion time was recorded; paired t-tests with Bonferroni correction assessed differences. RESULTS: Compared with baseline, moderate blur alone (VA 0.4/–PH) lengthened reading by 15–20% and search by ~ 17%. Adding a PH doubled search time at normal VA (97.7 s to 162.7 s, p < 0.001) and nearly doubled it at VA 0.4 (114s to 189 s, p < 0.001). The most severe condition (VA 0.1/+PH, enlarged font) required 1.42 × baseline time for reading and 3.12 × for search. Enlarging print reduced acuity-related reading delays but paradoxically increased search times because the scan area expanded. CONCLUSIONS: Reading speed is significantly limited by VA, whereas visual search is dominated by VF integrity. A single fixed time allowance (e.g., + 20–40 min) cannot accommodate all impairment profiles. Our findings suggest that test-time accommodations should be scaled separately—approximately 1.4 × the baseline for severe blur and 3.1 × for combined blur with field loss—rather than applying a single fixed extension. Such task-specific adjustments offer a principled path toward equitable testing for candidates with diverse visual limitations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12886-026-04706-y.