The effect of central and peripheral luminance on visual acuity

Context: Lighting conditions significantly influence visual acuity (VA), visual function, and quality of life. Previous research highlighted a correlation between luminance and VA but left a gap in understanding the impact of surrounding luminance. This study focused on investigating the effects of both central and peripheral luminance on VA. Purpose: This study aimed to investigate the influence of both central and surrounding luminance on VA through distance VA measurements. Settings and Design: A dual‑component lighting system was utilized, comprising a self‑illuminated ETDRS chart and a skyLED system for consistent surrounding illumination. Two experimental setups were conducted: the first varied the central luminance (25 ± 2–341 ± 10 cd/m2), while the second maintained a constant central luminance (150 ± 5 cd/m2) and varied the surrounding luminance (4 ± 2 cd/m2 OFF–105 ± 10 cd/m2 ON). Methods: Sixty‑six participants with refractive errors between 0.0 D and −2.75 D were tested under various lighting conditions. Both uncorrected refractive error (URE) and corrected refractive error (CRE) eyes were evaluated. Statistical Analysis Used: Paired t‑tests were used to evaluate the statistical significance of differences in VA scores. Results: Experiment 1 demonstrated a significant increase in VA scores, with mean improvements of −0.120 LogMAR for URE eyes and −0.073 LogMAR for CRE eyes as chart luminance increased from 26 cd/m2 to 153 cd/m2. Experiment 2 further showed a notable improvement in VA scores under varied surrounding luminance conditions, with mean improvements of − 0.118 LogMAR for URE eyes and −0.073 LogMAR for CRE eyes as luminance increased from 4 cd/m2 to 102 cd/m2. Conclusions: This study emphasizes the significant impact of both central and peripheral luminance on VA. The introduction of the skyLED lighting system underlines the importance of optimal lighting for visual performance. © 2024 Indian Journal of Ophthalmology.