Towards a framework for light-dosimetry studies: Quantification metrics

Abstract

Light dosimetry aims to measure personal light exposure with wearable sensors, which is a complex multistep procedure. The resulting data may be used to investigate non-visual effects of light in real-life settings, to validate laboratory findings and answer questions pertaining to implications in applied contexts. However, personal light exposure patterns are usually complex and can be quantified in many ways. Various measurement and analysis methods have been applied across previous studies, complicating comparability and interpretation of results. To improve the quality and comparability of light-dosimetry research, a framework with consensus guidelines for light-dosimetry procedures is needed. To provide the groundwork towards such a framework, we reviewed previous light-dosimetry studies to identify considerations regarding measurement and data quantification. Here, we review metrics for quantifying light-dosimetry data in terms of the characteristics known to modulate non-visual responses. Overall, various metrics have been employed across studies, with several metrics for each characteristic. We provide a description of each metric, discuss their properties and provide example calculations for the application to light-dosimetry data. Moreover, we propose considerations for data quantification and possible research strategies for future studies. To facilitate exploration and use of the identified metrics, corresponding functions are provided in an openly accessible R-package.

Editorial: The many faces of sustainability in lighting research

“…In situ light exposure can be challenging to gauge due to the variability in occupants' position and field of view but using light-dosimeters (wearable devices) can enable estimating occupants' personal light exposure to light stimulus with the caveat of reduced accuracy compared to controlled lab conditions. 12 Hartmeyer and Andersen 13 underlined the need for consensus guidelines for light-dosimetry procedures. They review metrics for quantifying light-dosimetry data, discuss metric properties and propose considerations for data quantification and possible research strategies for future studies Sustainability in lighting research is innately multifaceted, aiming to address various environmental, economic and social challenges associated with lighting systems and practices.…”

Human-Centric Lighting Research and Policy in the Melanopsin Age

“…A growing set of evidence has examined the impact of light and light exposure under lifelike, real-world conditions. These studies, enabled by the availability of small, wearable light loggers ( Hartmeyer & Andersen, 2023 ; Hartmeyer et al, 2022 ; Spitschan et al, 2022 ), have established some key links between real-world light exposure and a range of outcomes, such as sleep architecture ( Wams et al, 2017 ), circadian entrainment ( Woelders et al, 2017 ), and body mass index (BMI) ( Reid et al, 2014 ).…”

“…However, for sample sizes that may yield evidence for the genetic underpinnings, there are no convenient assays for NIF function that can be deployed at scale. Ways forward could lie in a variety of different techniques, including miniaturized wearable light sensors ( Casson, 2023 ; Hartmeyer & Andersen, 2023 ; Hartmeyer et al, 2022 ; Joyce et al, 2020 ; Mohamed et al, 2021 ; Spitschan et al, 2022 ; Stampfli et al, 2023 ); smartphone-deployed apps probing alertness, cognition, and other parameters ( Gardesevic et al, 2022 ; Klein et al, 2021 ; Shatte & Teague, 2020 ); ambulatory systems for measuring hormone concentrations continuously ( Grant et al, 2022 ); and novel nonintrusive ways of measuring sleep–wake rhythms over long periods ( Alkalih et al, 2022 ).…”

Integrative Lighting Aimed at Patients with Psychiatric and Neurological Disorders

“…It seems to us that many of the limitations of the current practice for field measurements could be alleviated by using circadian light dosimeters [64][65][66]. However, to date, and to the best of our knowledge, there are no such devices available on the market, apart from the Lys button from Lys technologies [67].…”