Human responses to graded light exposure in the temporal visual field during central visual tasks

Indoor light reaches occupants through a visual field simultaneously used for ongoing visual activity, yet ocular exposure is commonly characterized by scalar measures of magnitude and spectrum. We examined responses to graded temporal-field light exposure during central visual tasks in 33 participants under four within-subject conditions corresponding to regional melanopic spatial exposure levels of 0.00, 30.79, 61.58, and 92.50 lx; eye-level melanopic equivalent daylight illuminance (mEDI) was reported as the standardized scalar exposure measure. Electrodermal, electroencephalographic, cognitive, and subjective responses were assessed.

Outcome-specific analyses showed higher resting-state mean skin conductance response amplitude under all active conditions, higher 2-back accuracy, lower visual comfort at 92.50 lx, lower positive affect at 61.58 lx, and exposure-related differences in prefrontal β and parietal α2 power; Dimensional Change Card Sort performance showed no significant condition effect. After Holm correction across 25 omnibus tests, only 2-back accuracy and six prefrontal β/parietal α2 effects remained significant. Regional melanopic spatial exposure was used as an exploratory, study-specific geometric descriptor of melanopically weighted light, not a biological dose; its incremental explanatory or predictive value beyond eye-level mEDI was not established.

The design cannot separate spatial organization from melanopic magnitude or distinguish melanopsin-mediated contributions from conventional visual/optical mechanisms. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. College of Home and Art Design, Northeast Forestry University, Harbin, 150040, China College of Control and Information Engineering, Northeast Forestry University, Harbin, 150040, China The authors declare no competing interests.

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To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/. He, Y., Li, B., Du, Y. et al. Human responses to graded light exposure in the temporal visual field during central visual tasks.