luox: validated reference open-access and open-source web platform for calculating and sharing physiologically relevant quantities for light and lighting

Abstract

Light exposure has a profound impact on human physiology and behaviour. For example, light exposure at the wrong time can disrupt our circadian rhythms and acutely suppress the production of melatonin. In turn, appropriately timed light exposure can support circadian photoentrainment. Beginning with the discovery that melatonin production is acutely suppressed by bright light more than 40 years ago, understanding which aspects of light drive the 'non-visual' responses to light remains a highly active research area, with an important translational dimension and implications for "human-centric" or physiologically inspired architectural lighting design. In 2018, the International Commission on Illumination (CIE) standardised the spectral sensitivities for predicting the non-visual effects of a given spectrum of light with respect to the activation of the five photoreceptor classes in the human retina: the L, M and S cones, the rods, and the melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs). Here, we described a novel, lean, user-friendly, open-access and open-source platform for calculating quantities related to light. The platform, called luox, enables researchers and research users in vision science, lighting research, chronobiology, sleep research and adjacent fields to turn spectral measurements into reportable quantities. The luox code base, released under the GPL-3.0 License, is modular and therefore extendable to other spectrum-derived quantities. luox calculations of CIE quantities and indices have been endorsed by the CIE following black-box validation.

Power Analysis for Human Melatonin Suppression Experiments

“…As a consequence, the results here hold independent of the light quantification metrics, and using a simple scaling factor, can be expressed as melanopic equivalent daylight illuminance (mEDI) [ 31 ]. Following calculations with luox [ 32 ], the melanopic EDIs were 1.58 lx (nominal 10 photopic lx), 48.24 lx (nominal 100 photopic lx), 99.76 lx (nominal 200 photopic lx), 206.33 lx (nominal 400 photopic lx) and 1106.21 lx (nominal 200 photopic lx) in the original data set.…”

Integrative Lighting Aimed at Patients with Psychiatric and Neurological Disorders

“…For data processing, the measured spectra were exported into a *.CSV (commaseparated) file, then uploaded to the Luox platform [83] for the calculation of the relevant quantities (including illuminance, chromaticity, α-opic irradiance, and α-opic daylight illuminance). The software used for the Luox calculation is endorsed by CIE, having made a black-box evaluation of the software as of 11 February 2021, finding that the software performs satisfactorily in calculating the quantities and indices derived from CIE publications [83,84].…”

“…The use of the Luox platform [83] ensured that the calculations of key parameters were accurate and aligned with the CIE requirements [23,84]. The template made using the Canva platform provides a straightforward and visual presentation for each measurement point, making it easier to get an overview of the light level from both visual and nonvisual perspectives.…”

The impact of road lighting on road user alertness in the evening

“… Alpha-opic equivalent daylight illuminances calculated using luox from Spitschan et al . 40 a Vertical illuminances at eye level (1.5 m above the floor). …”

“…Light settings (illuminance and SPD-related metrics) used in the adaptation and test conditions Alpha-opic equivalent daylight illuminances calculated using luox from Spitschan et al40 a Vertical illuminances at eye level (1.5 m above the floor).…”