Usability and Acceptability of a Corneal-Plane α-Opic Light Logger in a 24-h Field Trial

Abstract

<b><i>Introduction:</i></b> Exposure to light fundamentally influences human physiology and behaviour by synchronising our biological clock to the external light-dark cycle and controlling melatonin production. In addition to well-controlled laboratory studies, more naturalistic approaches to examining these “non-visual” effects of light have been developed in recent years. As naturalistic light exposure is quite unlike well-controlled stimulus conditions in the laboratory, it is critical to measure light exposure in a person-referenced way, the “spectral diet.” To this end, light loggers have been developed to capture personalised light exposure. As an alternative to light sensors integrated into wrist-worn actimeters, pendants, or brooch-based light loggers, a recently developed wearable light logger laterally attached to spectacle frames enables the measurement of biologically relevant quantities in the corneal plane. <b><i>Methods:</i></b> Here, we examine the usability and acceptability of using the light logger in an undergraduate student sample (<i>n</i> = 18, mean±1SD: 20.1 ± 1.7 years; 9 female; Oxford, UK) in real-world conditions during a 24-h measurement period. We probed the acceptability of the light logger using rating questionnaires and open-ended questions. <b><i>Results:</i></b> Our quantitative results show a modest acceptability of the light logger. A thematic analysis of the open-ended questions reveals that the form factor of the device, in particular, size, weight, and stability, and reactions from other people to the wearer of the light logger, were commonly mentioned aspects. <b><i>Conclusion:</i></b> In sum, the results indicate the miniaturisation of light loggers and “invisible” integration into extant everyday objects as key areas for future technological development, facilitating the availability of light exposure data for developing personalised intervention strategies in both research, clinical and consumer contexts.

Protocol for a prospective, multi-centric, cross-sectional cohort study to assess personal light exposure

“…Furthermore, the studies by Brown et al (2021) and Cheng et al (2021) describe novel, non-physiological methods to predict individuals' circadian phases. Finally, the studies by (Balajadia et al, 2023) and van Duijnhoven et al (2017) highlight the limitations of current corneal-plane light loggers placed laterally on glasses in ensuring high-quality data experience by participants.…”

Power analysis for personal light exposure measurements and interventions

“…Developments in the eld of miniaturized sensor platforms have reduced the cost and size of these devices, while computational power and interfaces improved. We see a surge in studies using wearable light sensors in recent years, which is likely fueled by these developments in combination with increasing interest from the scienti c community [1,[11][12][13][14][15][16]]. This trend is likely to continue and bring new challenges for researchers working on the non-visual effects of light.…”