Abstract Background This study aimed to evaluate the individual and joint effects of reduced visual acuity (VA) and restricted visual field (VF) on the reading performance of Chinese readers under standardized low-vision simulation. Methods Eighty-one adults were randomized to three simulated distance VA levels using Bangerter foils: normal VA (≤ 0.30 logMAR), mild VA impairment (VAI) (0.30 logMAR 0.52 logMAR). VF was simulated as normal, moderate VF impairment (VFI) (20° radius), or severe VFI (10° radius) using specially designed goggles. Reading speed (RS) was measured using the Chinese International Reading Speed Texts (IReST). Maximum reading speed (MRS), reading acuity (RA), and critical print size (CPS) were measured using the Chinese Reading Acuity Chart. RS and MRS were analyzed using linear mixed-effects models, whereas RA and CPS were analyzed using generalized estimating equations with a gamma distribution and log link. Results Reduced VA and restricted VF significantly decreased RS and MRS. Compared with normal VA, mild VAI reduced RS by 80.6 characters per minute (cpm, 95% CI: − 98.4 to − 62.7) and MRS by 52.9 cpm (95% CI: − 65.3 to − 40.6), while moderate VAI reduced MRS by 63.3 cpm (95% CI: − 75.6 to − 50.9). Moderate VFI and severe VFI reduced RS by 9.5 cpm (95% CI: − 16.7 to − 2.4) and 38.1 cpm (95% CI: − 45.3 to − 31.0), and reduced MRS by 11.0 cpm (95% CI: − 19.0 to − 3.1) and 25.2 cpm (95% CI: − 33.1 to − 17.3), respectively. Under combined impairment, participants with mild VAI and severe VFI demonstrated an additional reduction in RS of − 20.1 cpm (95% CI: − 30.2 to − 10.0). Additional reductions in MRS were observed in participants with moderate VAI combined with moderate VFI (− 20.6 cpm; 95% CI: − 31.8 to − 9.4) and severe VFI (− 40.0 cpm; 95% CI: − 51.2 to − 28.8). RA and CPS were primarily influenced by VA. VF restriction only showed small effects on RA and no meaningful effect on CPS. Conclusions Both reduced VA and VF constriction significantly impaired reading performance, with VA loss emerging as the dominant factor. Under standardized simulation of low-vision conditions, combined impairments produced additional reductions in RS and MRS. These findings support the evaluation of reading performance in low-vision rehabilitation and earlier visual rehabilitation in patients with combined VA and VF impairments. Trial registration The study was registered with the Chinese Clinical Trial Registry (ChiCTR2400080206).
Luo et al. (Fri,) studied this question.