Biology subjects

Spitschan, M.

Publications and source records attributed to Spitschan, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Phasic pupil responses to melanopsin- and cone-directed stimulation remain stable across circadian time

Human pupil responses vary with time of day, but whether this reflects circadian modulation of specific photoreceptor pathways is unclear. Twelve healthy adults completed repeated pupillometry during a 40-hour ultra-short sleep-wake protocol that limited sustained wakefulness; data from eight met the quality-control criteria and were analysed. This design was intended to limit progressive accumulation of homeostatic sleep pressure across sampled circadian phase. During wake episodes, 0.4-Hz silent-substitution stimuli targeted broadband flux, melanopsin, luminance, L-M cone-opponent, or S-cone pathways. Salivary melatonin provided participant-specific period estimates. We separated slow tonic constriction from phasic pupil tracking and compared hierarchical circadian cosinor models with constant-level models. Constant-level models were favoured for phasic amplitude in all five conditions (log10 BF10 = -3.36 to -1.10). They were also favoured for tonic minimum in four conditions; L-M favoured the circadian model (log10 BF10 = 0.67), but the evidence was imprecise. Under the tested contrast, adaptation, and frequency, these data do not support circadian modulation of phasic photoreceptor-directed pupil tracking. Other metrics and smaller or non-sinusoidal effects remain possible.

neuroscience↗

bioRxiv2026

Age-corrected model for predicting pupil diameter in real-world conditions from melanopic equivalent daylight illuminance

Purpose: Pupil diameter in daily life depends on both the light reaching the eye and the observer's age, but established prediction formulas require laboratory quantities that are rarely measured in natural environments. We developed a compact age-corrected model that predicts pupil diameter from melanopic equivalent daylight illuminance (mEDI). Methods: We used an existing field dataset in which binocular pupil diameter and near-corneal spectral irradiance were recorded while 83 adults aged 18-87 years moved through indoor and outdoor environments. The analysis included 10,082 valid paired observations. We fitted a bounded sigmoid relating pupil diameter to mEDI and age, with each participant given equal influence, and assessed prediction in participants excluded from model fitting. Performance was compared with simpler models, a flexible generalised additive model (GAM), and Watson-Yellott predictions based on assumed field geometry. Results: Pupil diameter decreased smoothly as mEDI increased. Age primarily reduced the difference between pupils in dim and bright conditions, by 0.768 mm per decade, while the predicted bright-light diameter changed little with age. In held-out participants, the bounded model had a participant-balanced root mean squared error (RMSE) of 0.630 mm and mean absolute error of 0.537 mm. The GAM had a slightly lower point-estimate RMSE of 0.610 mm, but the difference was small and uncertain. The bounded model outperformed the tested log-linear, reduced, age-only, and Watson-Yellott alternatives. Conclusion: Age and mEDI are sufficient to provide useful population-average pupil predictions across the observed adult age and real-world light range. The model is transparent, physiologically bounded, and nearly as accurate as a flexible GAM, but predictions approaching darkness remain uncertain because valid mEDI measurements were not available in that range.

neuroscience↗

bioRxiv2026

Toward scalable ambulatory light dosimetry: sensor-placement bias under naturalistic conditions

BackgroundPersonal light dosimeters enable exposure assessment under free- living conditions, but sensors are rarely positioned near the eyes--the relevant site for visual and non-visual responses. Chest and wrist placement may improve adherence and scalability, yet placement-dependent error and its consequences for derived outcomes remain insufficiently characterised. ObjectiveTo quantify how chest and wrist placement affects time-resolved estimates of eye-level light exposure across naturalistic contexts and derived exposure metrics. MethodsWe analysed concurrent 10-s melanopic equivalent daylight illuminance measurements from identical dosimeter models at the glasses, chest, and wrist across eight sites in seven countries. Melanopic equivalent daylight illuminance was compared at two analytical scales. Generalised additive mixed models quantified time-resolved placement error across contexts (N=787 participant-days), and mixed- effects models compared 54 daily metrics (N=604 participant-days). Hierarchical bootstrap resampling quantified the precision of population-average metric bias across participant numbers and monitoring durations. ResultsBody-worn dosimeters generally underestimated eye-level exposure. Across categorical contexts, estimated mean errors ranged from -23.1% to -4.2% at the chest and from -54.7% to -30.3% at the wrist, with larger errors generally observed at night. Nineteen of 54 chest-derived and 27 of 54 wrist-derived metrics differed nominally from glasses. Among these, median absolute bias was 5% at both placements, but maxima reached 50% and 84%, respectively. Timing outcomes were comparatively insensitive, whereas level and temporal-dynamics outcomes were more sensitive. With seven days per participant, the class-median bias standard deviation reached the 5% precision tolerance with 2-16 participants for all classes except temporal dynamics, which required 33 at the chest and 59 at the wrist. SignificanceDosimeter-placement validity depends on analytical scale and exposure construct. Chest placement can support scalable studies focused on aggregated timing or duration outcomes, whereas wrist placement introduces greater and less predictable bias. Near-eye measurement remains preferable for small- sample studies, time-resolved exposure levels and temporal-dynamics analyses.

physiology↗

bioRxiv2026

Audiovisual stimulation using wearable shutter glasses robustly evokes 40 Hz neuronal activity but does not modulate associative memory

Audiovisual stimulation is a promising approach for studying and modulating human neuronal gamma (>30 Hz) oscillations and associated memory processes. Portable setups can increase ecological validity and therapeutic potential, but options remain limited. See-through shutter glasses are a new mobile technology that adds a visual flicker effect to what the user naturally sees. Here, we validated this method in a multisensory, cognitively relevant setting. We leveraged a previous experimental design from our lab, aiming to A) characterise the neuronal gamma activity evoked by shutter glasses, and B) conceptually replicate the previously reported effect of audiovisual gamma stimulation on memory accuracy, in line with a Spike Timing Dependent Plasticity model. We recorded high-density Electroencephalography (EEG) from 24 healthy participants during an associative memory task. Video-sound pairs were presented with the sound amplitude-modulated at 40 Hz and 40 Hz visual flicker elicited by the shutter glasses, with a phase offset between both modalities. The visual flicker preceded the auditory modulation by 90 or 270 degrees. Participants were asked to remember the video-sound associations. They also underwent a visual-only condition and an electrically equivalent control condition. EEG evoked power and phase coherence were reconstructed at source level and analysed along with behavioural accuracy. As expected, the shutter glasses robustly increased EEG evoked power and phase coherence at 40 Hz compared to the control condition. Effects were widespread and stronger than in a previous study not using shutter glasses. However, we did not replicate the previously reported effects of audiovisual phase offsets on memory accuracy. This could be due to reduced statistical power or methodological differences. Nonetheless, the validation of shutter glasses in a multisensory setting and the EEG analysis software, now improved and open source, enable important further investigations of audiovisual gamma stimulation in research and clinical settings.

neuroscience↗

bioRxiv2026

Individual, behavioural, and environmental determinants of personal light exposure in daily life: A multi-country wearable and experience-sampling study

Light supports circadian regulation and is associated with non-communicable diseases, yet ocular exposure patterns remain poorly understood. We recruited 191 adults across nine sites in seven countries, combining diaries and contextual reports with near-eye (141 participants; 816 participant-days) and complementary chest-level measurements (154 participants; 902 participant-days). In near-eye analyses, only 24.0% of recorded daytime minutes met the recommendation of at least 250 lx melanopic equivalent daylight illuminance; 63.3% of pre-sleep and 87.7% of bedside sleep-environment minutes met their respective limits. Variation among people and days within sites exceeded that among sites (ratio 1.99; 95%-CI, 1.29-4.77). In hourly models, light source and setting contributed the largest shares of fitted variation after time of day. Site-average outdoor exposure was 9.35 times that while awake at home (95%-CI, 6.95-12.59; 714.2 versus 76.4 lx). This baseline identifies a daytime exposure gap and supports testing interventions in everyday settings to improve light exposure and health.

physiology↗

bioRxiv2026

Associations between habitual light exposure-related behaviors and sleep timing and sleep complaints in an international community sample

Sleep is essential for health and light is an important environmental signal influencing its timing, quality, and regulation. Retinal light exposure reflects the interplay between environmental illumination and behavioral choices, yet it remains unclear which habitual light exposure-related behaviors meaningfully impact sleep outcomes. In this preregistered analysis, we examined associations between these behaviors, sleep timing, and sleep complaints in a large, international community sample (N = 774, Mage = 32.6 {+/-} 14.6 years). Participants completed the Light Exposure Behavior Assessment (LEBA), with four behavioral domains included in the analyses. Sleep timing, sleep disturbances and sleep-related daytime impairment were measured using established questionnaires. Bayesian analyses indicated that time spent outdoors and device use in bed were most strongly associated with sleep outcomes. Greater time outdoors was linked to earlier sleep timing and fewer sleep complaints, whereas more frequent device use in bed was associated with greater sleep disturbance and daytime impairment. Morning and daytime lighting practices and evening light control showed no conclusive evidence. Together, these findings highlight the relevance of everyday light exposure-related behaviors for sleep and support behavioral approaches to promoting healthy sleep in real-world contexts.

neuroscience↗

bioRxiv2025

Circadian timing does not modulate human chromatic temporal contrast sensitivity

IntroductionPrevious studies have reported diurnal variations in colour perception and luminance contrast sensitivity, suggesting modulation of visual processing by the circadian pacemaker. To clarify potential time-of-day effects, we examined whether cone-mediated temporal contrast sensitivity is modulated by circadian timing. MethodsWe disentangled circadian and homeostatic influences on human visual performance using a 40-hour forced desynchrony protocol. Twelve participants (5 women, 24.4 {+/-} 2.9 years, range 19-30) followed a repeating 3.75 h cycle comprising 2 h 30 min of wakefulness and 1 h 15 min of sleep under constant environmental conditions. Circadian phase was determined from 46 salivary melatonin samples collected per participant. During wake periods, participants repeatedly completed temporal contrast sensitivity tasks at 2 Hz and 8 Hz, probing luminance (L+M+S) and chromatic (L-M, S-cone-directed) modulations. We tested for circadian modulation of visual performance by comparing multilevel cosinor and uninformative Bayesian models. ResultsAll participants showed robust melatonin rhythms (mean{tau} = 24.18 {+/-} 0.39 h). Bayesian inference provided decisive evidence against circadian variation in luminance or chromatic contrast sensitivity. DiscussionWithin this controlled protocol, we found no detectable near-24-hour modulation of cone-mediated temporal contrast sensitivity. Previously reported time-of-day effects may instead reflect homeostatic influences, pupil-linked changes in retinal illuminance, or mechanisms outside the cone-mediated pathways probed here. SignificanceBy separating circadian phase from sleep-wake-related influences, this study clarifies when circadian modulation of visual performance can, and cannot, be inferred.

neuroscience↗

bioRxiv2025

Photoreceptor-specific scene statistics reveal melanopic structure in natural environments

Natural scenes shape visual perception and non-visual responses, yet the melanopsin pathway, the retinas key circadian input, is rarely quantified in this context. We measured spectral and spatial properties of 671 natural scenes: indoor scenes without windows (n=115), indoor scenes with windows (n=194), and outdoor scenes (n=362), across all five human photoreceptors. Radiance and photometric metrics increased systematically from windowless indoor view (mean melanopic EDI 280 lx) to indoor scenes with window view (2386 lx) to outdoor scenes (12,142 lx), with melanopic and photopic illuminance strongly correlated (r {approx} 0.9, p < 10-5). Beyond overall -opic exposure, melanopic input exhibited structured spatial variation. RMS contrast ranged from 0.001 to 0.365, lowest without windows and highest outdoors, and correlated with melanopic luminance indoors with windows (r = 0.495) and outdoors (r = 0.477) but not windowless scenes (r = 0.026). Melanopic amplitude spectra followed 1/f -like power laws, steeper slopes indoors (modal{approx} -1.4) and flatter outdoors (modal{approx} -1.1), revealing photoreceptor-resolved regularities in natural melanopic input.

neuroscience↗

bioRxiv2025

Improving the utility and accuracy of wearable light loggers and optical radiation dosimeters through auxiliary data, quality assurance, and quality control

Wearable light loggers and optical radiation dosimeters are increasingly used in chronobiology and circadian health research, yet their data often lack contextual information (e.g., sleep, activity, environmental conditions) and may be compromised by non-wear periods, compliance issues, or technical faults. To address these limitations, we conducted interviews (n=21) and a survey (n=16) with domain experts to distill and iteratively develop auxiliary data and quality-control strategies aimed at improving the accuracy and interpretability of wearable light measurements. From this process, we established a six-domain auxiliary data framework encompassing wear/non-wear logging, sleep monitoring, light-source context, participant behaviour, user experience, and environmental light levels. Survey responses showed strong consensus on the value of auxiliary information (mean importance 4.0/5), with sleep and wear-time tracking rated as the most essential additions. To support practical adoption, we provide implementation tools, including extensions to the open-source R package LightLogR, enabling streamlined integration of wearable and auxiliary data as well as systematic quality assurance and control. Experts agreed that combining contextual records with rigorous QA/QC procedures substantially improves the reliability of field-collected light-exposure data. These recommendations and tools aim to help researchers in chronobiology, wearable sensing, and health sciences maximise data quality and enhance interpretation in real-world light-exposure studies.

neuroscience↗

bioRxiv2025

Analysis of human visual experience data

Exposure to the optical environment -- often referred to as visual experience -- profoundly influences human physiology and behavior across multiple time scales. In controlled laboratory settings, stimuli can be held constant or manipulated parametrically. However, such exposures rarely replicate real-world conditions, which are inherently complex and dynamic, generating high-dimensional datasets that demand rigorous and flexible analysis strategies. This tutorial presents an analysis pipeline for visual experience datasets, with a focus on reproducible workflows for human chronobiology and myopia research. Light exposure and its retinal encoding affect human physiology and behavior across multiple time scales. Here we provide step-by-step instructions for importing, visualizing, and processing viewing distance and light exposure data. This includes time-series analyses for working distance, biologically relevant light metrics, and spectral characteristics. The tasks are standardized through the open-source R package LightLogR. By leveraging a modular approach, the tutorial supports researchers in building flexible and robust pipelines that accommodate diverse experimental paradigms and measurement systems.

neuroscience↗

bioRxiv2025

Non-linear effects of evening light exposure on cognitive performance

In humans, exposure to light can impact alertness and cognitive performance. These cognitive effects of light are mediated by the intrinsically photosensitive retinal ganglion cells (ipRGCs) expressing the photopigment melanopsin, which signals environmental light in addition to the cone- and rod-mediated pathways. Most studies investigating the cognitive effects of light have focused on alertness, raising the question how higher-level cognitive tasks such as working memory are modulated by light. This study investigated the dose-response relationship for alertness, cognitive performance and mental workload. Each level of melanopic illuminance (ranging from 1 lx to 595 lx melanopic EDI) was evaluated over separate days with a six-hour exposure in a controlled climate chamber with artificial lighting. Participants (n=16, 10 female, 27.4{+/-}2.5 years), completed the Psychomotor Vigilance Test (PVT) and n-back task every 30 minutes to assess reaction time, attention, and working memory, alongside subjective evaluations through questionnaires. The results suggest an inverted U-shaped correlation between cognitive functions and melanopic EDI and a U-shaped relationship between subjective assessments and melanopic EDI. Extreme lighting conditions in our stimulus set - both dim (1 lx melanopic EDI) and bright (595 lx melanopic EDI) - were associated with increased sleepiness and perceived workload, quicker reaction times, and diminished cognitive performance. Conversely, moderate illuminance levels (10 lx melanopic EDI and 70 lx melanopic EDI) positively influenced cognitive performance and mental workload but resulted in slower reaction times. This study illustrates that the relationship between melanopic EDI levels and cognitive performance does not follow a linear dose-response pattern, indicating a complex strategy for resource allocation in cognition.

neuroscience↗

bioRxiv2025

Joint infrared pupil images and near-corneal-plane spectral light exposure data under natural conditions across the adult lifespan

Factors influencing pupil size can be experimentally controlled or held constant in laboratory experiments, but how the pupil reflects changes in retinal input from the visual environment in real-world viewing conditions has yet to be captured in a large, age-diverse sample. In this dataset, we address this research gap by collecting data in a hybrid field-laboratory experiment (N=83, 43 female, age range 18–87 years) using a custom-built, wearable, video-based eye tracker with a spectroradiometer measuring spectral irradiance in the approximate corneal plane, resulting in a total of valid 29,664 recorded spectral irradiance and eye image pairs along with 83 approximately 3-minute-long calibration videos. After an initial 3-minute calibration procedure, 10-minute dark-adaptation period and a 14-minute controlled laboratory light condition, participants moved in and between indoor and outdoor environments of varying spectral irradiance for ∼25–35 minutes and performed a range of everyday tasks. This dataset may provide a basis for developing algorithms for pupil detection, processing, and prediction under natural conditions.

neuroscience↗

bioRxiv2025

Standardized and calibrated light stimuli via head-mounted displays for investigating the non-visual effects of light

Light influences human physiology profoundly, affecting the circadian clock and suppressing the endogenous hormone melatonin. Experimental studies often employ either homogenous full-field stimulation, or overhead illumination, which are hard to standardize across studies and laboratories. Here, we present a novel technique to examine non-visual responses to light using virtual-reality (VR) head-mounted displays (HMDs) for delivering standardized and calibrated light stimuli to observers in a reproducible and controlled manner. We find that VR HMDs are well-suited for delivering standardized stimuli defined in luminance and across time, with excellent properties up to 10 Hz. We examine melatonin suppression to continuous luminance-defined light stimuli in a sample of healthy participants (n=32, mean{+/-}SD age: 27.2{+/-}5.6), and find robust melatonin suppression in 24 out of 32 participants (75% of the sample). Our findings demonstrate that VR HMDs are well-suited for studying the mechanisms underlying human non-visual photoreception in a reproducible and standardized fashion.

neuroscience↗

bioRxiv2025

dlmoR: An open-source R package for the dim-light melatonin onset (DLMO) hockey-stick method

The dim-light melatonin onset (DLMO) is a commonly used circadian marker indicating the start time of evening melatonin synthesis in humans. Several quantitative techniques have been developed to determine DLMO from melatonin time series, including fixed- or variable-threshold techniques and the hockey-stick method developed by Danilenko et al. (2014). Here, we introduce dlmoR, an open-source (MIT License) implementation of the hockey-stick method written in R. Our clean-room implementation follows the original algorithm description, supported by iterative validation against the existing binary executable. We benchmarked dlmoR on 112 melatonin time series datasets from two independent studies (Heinrichs and Spitschan (2025); Blume et al. (2024)) and found high agreement with the reference implementation: mean discrepancies were -1.482 {+/-} 21.7 minutes for the Heinrichs and Spitschan (2025) dataset and 1.165 {+/-} 28.5 minutes for the Blume et al. (2024) dataset, with circular correlation coefficients of 0.964 and 0.986, respectively. Paired t-tests (p > 0.05) indicated no systematic difference or bias between methods. Beyond reproducing the hockey-stick algorithm, dlmoR adds capabilities absent from the original executable, including interactive visual diagnostics and bootstrapped confidence intervals, offering qualitative and quantitative views of estimation uncertainty. It supports programmatic, reproducible analysis of melatonin profiles, including batch processing and parameter manipulation. Leveraging this flexibility, we evaluated the sensitivity of the hockey-stick algorithm to controlled changes in sampling schedules, threshold levels, data completeness, and noise. Moderate changes, such as small timing jitter, limited data loss, or modest threshold shifts, kept estimates stable within {+/-}10 minutes, whereas pronounced alterations to sampling schedules, large multi-point deletions, or substantial threshold changes delayed estimates by over 40 minutes or prevented estimation. This analysis reveals fundamental limitations in the algorithms internal mechanics, particularly in how it identifies the onset window and models the melatonin rise, and underscores the need for new uncertainty-aware approaches to DLMO estimation.

neuroscience↗

bioRxiv2025

Physiologically-relevant light exposure and light behaviour in Switzerland and Malaysia

Light synchronises the internal clock with the external light-dark cycle. Keeping this alignment benefits health and prevents diseases. Quantifying light exposure is, therefore, vital for effective prevention. Since light exposure depends on photoperiod, culture, and behaviour, we investigated objective light exposure and individual light-related behaviour in Switzerland and Malaysia. In this observational field study, participants (N=39) wore a calibrated melanopic light logger at chest level for 30 consecutive days. At baseline and study end, the Pittsburgh Sleep Quality Index was assessed, and every 3 to 4 days, the Light Exposure Behaviour Assessment (LEBA) was filled. Our pre-registered analyses reveal that participants in Switzerland experienced brighter days (+3.16 times the average mel EDI) and spent more time (x1.9 times the duration) in daylight levels per hour of daylight, had [~]1.5h later bright light exposure in the afternoon, and stayed over 1h longer in dim light conditions before bedtime. LEBA scores did not differ between Malaysia and Switzerland, and LEBA items were stable over time. LEBA items also correlated with objective light exposure variables in Switzerland but not Malaysia, with a medium effect size (range of absolute r=0.32-0.48). These results highlight cultural and geographical differences in light exposure. We showed that LEBA can be related to actual light exposure and is ecologically informative, but this varies by culture.

neuroscience↗

bioRxiv2025

Regulation of eye movements and pupil size in natural scenes

The visual diet of humans is complex in space, time, spectrum, and conse- quently the activation of the retinal photoreceptors. While analyses of natural scenes have yielded valuable insights, the naturalistic natural stimulus on the retina is not very well understood. In the present study, we performed eye tracking in naturalistic indoor and outdoor real-world scenes. We recorded pupil size, several saccade and fixation metrics, as well as subjective scene perception ratings derived from subjective questionnaires. For the first five seconds of eye tracking, the descriptive data analysis revealed significantly increased average saccade frequency (p =.0025), amplitude (p =.0049), peak velocity (p =.0072), as well as pupil size (p = 1.307e-09) in the indoor environ- ments. After this initial phase, these differences vanished, except for pupil size. Using an exploratory analysis on the whole 4-minute measurement, we found that saccade and fixation metrics, along with scene ratings, showed significantly different correlations between indoor and outdoor conditions. Despite the inherent constraints of such a naturalistic study (reduced ability to exert control over the precise task and the environmental conditions), we contend that the dataset holds substantial value for field of eye movement research, as it has effectively minimized confounding factors that have been prevalent in previous eye tracking studies. HighlightsO_LIIncreased amplitude, frequency, and peak velocity of saccades in real- world indoor environments within the initial 5 seconds of eye tracking C_LIO_LIDifferent correlations of eye movement metrics and subjective scene per- ception between real-world indoor and outdoor environments C_LIO_LIEstablishing an eye movement dataset of various saccade in fixation metrics in naturalistic real-world environments with reduced confounding factors C_LI

neuroscience↗

bioRxiv2024

How to deal with darkness: Modeling and visualization of zero-inflated personal light exposure data on a logarithmic scale

Personal light exposure, the pattern of ocular light levels across time under free-living conditions measured with wearable devices, has become increasingly important in circadian and myopia research. Very small measurement values in light exposure patterns, especially zero, are regularly recorded in field studies. These zero-lux values are problematic for commonly applied logarithmic transformations, and should neither be dismissed nor be unduly influential in visualizations and statistical models. Common approaches used in zero-inflated data sets fail in at least one of these regards. We compare four ways to visualize such data on a linear, logarithmic, hybrid, or symlog scale and we model the light exposure patterns with a generalized additive model by removing zero-lux values, adding a very small or -1 log10 lux value to the dataset, or using the Tweedie error distribution. We show that a symlog-transformed visualization displays relevant features of light exposure across scales, including zero-lux, while at the same time reducing the emphasis on the small values (<1 lux). Symlog is well-suited to visualize differences in light exposure covering heavy-tailed negative values. The open-source software package LightLogR includes the symlog transformation for easy access. We further show that small but not negligible value additions to the light exposure data of -1 log10 lux for statistical modelling allow for acceptable models on a logarithmic scale, while very small values distort results. We also demonstrate the utility of the Tweedie distribution, which does not require prior transformations, models data on a logarithmic scale, and includes zero-lux values, capturing personal light exposure patterns satisfactorily. Data from field studies of personal light exposure requires appropriate handling of zero-lux values in a logarithmic context. Symlog scales for visualizations and an appropriate addition to input values for modelling, or the Tweedie distribution, provide a solid basis.

neuroscience↗

bioRxiv2024

Collecting, detecting and handling non-wear intervals in longitudinal light exposure data

In field studies using wearable light loggers, participants often need to remove the devices, resulting in non-wear intervals of varying and unknown duration. Accurate detection of these intervals is an essential step during data pre-processing. Here, we deployed a multi-modal approach to collect non-wear time during a longitudinal light exposure collection campaign and systematically compare non-wear detection strategies. Healthy participants (n=26; mean age 28{+/-}5 years, 14F) wore a near-corneal plane light logger for one week and reported non-wear events in three ways: pressing an "event marker" button on the light logger, placing it in a black bag, and using an app-based Wear log. Wear log entries, checked twice daily, served as ground truth for non-wear detection, showing that non-wear time constituted 5.4{+/-}3.8% (mean{+/-}SD) of total participation time. Button presses at the start and end of non-wear intervals were identified in >85.4% of cases when considering time windows beyond one minute for detection. To detect non-wear intervals based on black bag use and lack of motion, we employed an algorithm detecting clusters of low illuminance and clusters of low activity. Performance was higher for illuminance (F1=0.78) than activity (F1=0.52). Light exposure metrics derived from the full dataset, a dataset filtered for non-wear based on self-reports, and a dataset filtered for non-wear using the low illuminance clusters detection algorithm showed minimal differences. Our results highlight that while non-wear detection may be less critical in high-compliance cohorts, systematically collecting and detecting non-wear intervals is feasible and important for ensuring robust data pre-processing.

neuroscience↗