Summary
This study measured spectral irradiance at the cornea across a range of natural and built environments during midday hours, converting data into key lighting metrics (circadian stimulus, Ev/Eh ratio, cylindrical illuminance) to assess their health-promoting potential. The findings indicate that more natural lit environments generally score better on these metrics, suggesting interior designers should prioritize higher illuminance, appropriate spectral composition, and favorable light distribution to replicate the benefits of natural light.
Key Findings
- Natural environments (seascapes, landscapes) consistently showed more favorable lighting metrics compared to interior architectural environments when measured at the cornea during midday hours.
- Circadian stimulus, vertical/horizontal illuminance ratio (Ev/Eh), and cylindrical illuminance were identified as the most relevant metrics for characterizing health-promoting lit environments.
- Interior environments were found to differ substantially from natural environments in spectral composition, illuminance levels, and light distribution — all factors linked to circadian and wellbeing outcomes.
- The study highlights that characteristics of the entire light field (not just the light source) must be considered when making health-based lighting recommendations.
Categories
The Science of Light: Evaluates lighting metrics including circadian stimulus, melanopic sensitivity, vertical/horizontal illuminance ratio, and cylindrical illuminance across natural and built environments.
Sleep & Circadian Health: Measures circadian stimulus across diverse lit environments to assess their potential for supporting healthy circadian entrainment.
Workplace Performance: Provides practical guidance for architectural and engineering designers seeking to optimize indoor lit environments for occupant health and wellbeing.
Author(s)
K van Creveld, K Mansfield
Publication Year
2020
Number of Citations
6
Related Publications
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice
Sleep & Circadian Health
- Phototransduction by retinal ganglion cells that set the circadian clock
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- The two‐process model of sleep regulation: a reappraisal
- Melanopsin is required for non-image-forming photic responses in blind mice
- Strange vision: ganglion cells as circadian photoreceptors
Workplace Performance
- Acute alerting effects of light: A systematic literature review
- Effects of artificial dawn and morning blue light on daytime cognitive performance, well-being, cortisol and melatonin levels
- Can light make us bright? Effects of light on cognition and sleep
- Kruithof's rule revisited using LED illumination
- Shining light on memory: Effects of bright light on working memory performance