Barrett · Scientific reports 2026 · before-after interventional study · n=?

LED lighting (350-650nm) undermines human visual performance unless supplemented by wider spectra (400-1500nm+) like daylight.

Level 4 - case-series / case-control

Pre-post interventional study with no control group or randomization described in the abstract

PubMed 41577976 · doi:10.1038/s41598-026-35389-6 · record verified 2026-08-26

What was done

Participants were exposed to broad-spectrum lighting (400–1500 nm+) supplementing standard LED lighting (350–650 nm) for two weeks. Visual performance was evaluated by measuring color contrast sensitivity, with follow-up testing extending up to two months after the supplemental lighting was removed.

What was found

The abstract reports a significant improvement in color contrast sensitivity following the two-week supplementation period, which persisted for two months after supplemental lighting was removed. No specific numerical values, effect sizes, baseline scores, confidence intervals, or exact p-values are reported in the abstract.

Why it matters

Standard LED lighting lacks longer wavelengths (deep red and near-infrared) that support mitochondrial respiration; this study suggests that broad-spectrum supplementation can improve visual contrast sensitivity with lasting effects.

Limits

The abstract does not state the sample size (n), participant characteristics (such as age or baseline health), or whether a randomized comparator group was used. Furthermore, no quantitative data are provided, and systemic cytokine impacts mentioned are speculative rather than measured trial outcomes.