Current recommendations for the use of red spectrum lighting in research animal facility planning and design (2026)

Dauchy, R. T.

Abstract

Light, an environmental factor much like noise, vibration, temperature, and humidity, has long been a concern to lighting engineers, biomedical researchers, and animal care personnel and requires great consideration in the design and planning of research animal facilities and laboratory facilities. In 2023, an International Workshop on Circadian and Neurophysiological Photometry was held in Manchester, UK, to address the problem of light in laboratory animal research. More specifically, appropriate lighting in animal facilities may support welfare and ensure that research animals enter experiments in an appropriate physiological and behavioral state. At this meeting, a Consensus View was developed by the leading light and circadian biology experts encompassing retina-driven effects of light in research animals, animal husbandry, and welfare. Use of red light and red light-filtered observation windows has occurred due to a misunderstanding of basic photobiology, taken by many to suggest that mice, for instance, do not respond to red light (that is, visually “see”) or even sodium light (approximately 589 to 600 nm) due to the known visual pigments of the mouse retina. Indeed, while mice are around 8 times less sensitive to red light and 7 times less sensitive to sodium light than human, recent irradiance response curve studies have shown that, while less sensitive, responses to long wavelength light do occur at higher intensities. To address the use of red light during the dark phase, one consideration may be to eliminate animal room observation windows altogether and to install the new, cost-effective, energy efficient “tunable” solid-state technology light-emitting diode (LED) lighting throughout the animal facility. Such LED lights are currently readily available through a host of vendors, and existing fluorescent light ballast systems may be easily retrofitted with the new, inexpensive technology.