Npj biological timing and sleepJul 20, 2026

Testing wearable light sensors for measuring daily lighting effects on body clock: color, brightness, position, eye sensitivity, and heat

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jul 21, 2026

Abstract

The Blue Iris Speck exhibited the highest photometric and data-logging accuracy among tested wearable light dosimeters.

Three wearable light dosimeters were evaluated: LYS Buttons, Blue Iris Specks, and Actiwatch Spectrum Plus.
Light measurements were taken under various lighting conditions to derive melanopic and photometric metrics.
The LYS Button was noted for its ease of use but had reduced accuracy compared to others.
The Actiwatch demonstrated the poorest photometric performance, raising concerns about its reliability for scientific applications.
Findings may guide future device development and experimental protocols in chronobiology and sleep research.

Simplified

Light is the primary stimuli for the entrainment of human circadian rhythms and holds enormous potential in aiding precision medicine. Laboratory studies highlight the roles of photic history, intensity, spectrum, and timing, but field translation gets complicated by real-world confounds. Measuring daily light exposure in realistic conditions requires an accurate, durable, and affordable wearable light dosimeter. Here, the spectral, spatial, and thermal performance of three wearable dosimeters (LYS Buttons, Blue Iris Specks, and Actiwatch Spectrum Plus) are investigated and benchmarked against a calibrated spectroradiometer under multipole lighting conditions. Light measurements taken by dosimeters under various lighting conditions are then used to calculate melanopic and photometric measures. The LYS Button was the easiest to use, albeit with reduced accuracy. The Blue Iris Speck had the highest photometric and data-logging accuracy. The Actiwatch had the poorest photometric performance, which raises caution for scientific use. The results inform device development and protocol design for chronobiology and sleep research. Future studies should evaluate and compare the performance of the dosimeters based on body-worn position.

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PubMed

Testing wearable light sensors for measuring daily lighting effects on body clock: color, brightness, position, eye sensitivity, and heat

Abstract

Full Text

Funding

Competing interests

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