Impact of Different Illumination Levels on Ocular Parameters in Healthy Adults During Book-Reading: An Experimental Study

Br Ir Orthopt J. 2026 Apr 1;22(1):84-91. doi: 10.22599/bioj.529. eCollection 2026.

ABSTRACT

AIM: To determine the role of different levels of illumination on various binocular vision parameters.

SETTINGS AND DESIGN: An experimental study was conducted from October 2024-June 2025.

METHODS: Thirty-four participants aged between 17 to 25 years with a mean age of 19.7 ± 2.4 years were included. Under different lighting conditions, i.e., low illumination (50 lux), medium illumination (100 lux), and high illumination (150 lux), the participants were instructed to perform reading tasks. The vergence and accommodative parameters for near were evaluated.

RESULTS: Observed changes in binocular vision parameters were associated with varying illumination levels. At 50 lux, the binocular accommodative facility (BAF) was 6.97 ± 0.86 cpm; at 150 lux, it was 10.55 ± 1.04 cpm. Higher illumination significantly enhanced vergence facility (VF), near point of accommodation (NPA), and near point of convergence (NPC). Brighter illumination enhanced both positive and negative fusional vergence (PFV and NFV) values, while MEM retinoscopy demonstrated decrease of accommodative lag.

CONCLUSIONS: Binocular vision parameters were higher significantly with high illumination which can enhance visual performance. Proper lighting is essential for eye exams, digital device use, and workspace design.

PMID:41937979 | PMC:PMC13045790 | DOI:10.22599/bioj.529