BACKGROUND AND AIMS
Eighty percent of youth with migraine report photophobia.1 It is unknown if photophobia leads to light avoidant behavior, which may further worsen light sensitivity and lead to sleep disruption. The technological development of wearable continuous light loggers makes it possible to address these open questions. Furthermore, these devices can distinguish light that stimulates the melanopic (i.e., circadian, or ‘blue light’) and photopic (i.e., image forming) visual pathways. The authors conducted an exploratory study2 in 20 youth with migraine to determine the feasibility of measuring daily light exposure with wearable light loggers and explore its relationship to migraine burden.
METHODS
Adolescents and young adults aged 15–21 years with a headache specialist-confirmed International Classification of Headache Disorders (ICHD)-3 diagnosis of migraine were recruited from Children’s Hospital of Philadelphia (CHOP) headache clinics. Each participant recorded 7 consecutive days of light logging data from the ActLumus (Condor Instruments, São Paulo, Brazil) light logger, worn as a pendant around the neck, paired with a text-based daily migraine symptom diary during a typical school week between November 2024–March 2025. Melanopic equivalent daylight illuminance (mEDI) was derived from light logger measurements and used to calculate percent time spent within recommended light exposure levels for the day (>250 lux mEDI), 3 hours prior to bedtime (<10 lux mEDI), and at night (<1 lux mEDI), optimal for circadian entrainment.3 To measure shifts in daily light exposure, 24-hour light exposure patterns for each participant were compared to the mean across participants.
RESULTS
Twenty participants (median age: 17 years; interquartile range [IQR]: 16–19; 70.0% female) completed 7 days of continuous light logger recording and daily headache diary. Data completion rates were high, with 136/140 (97.1%) useable days of light logger data and 100% adherence on the daily headache diary. While a range of disease burden was represented in the authors’ sample, participants tended towards more severe symptoms (Table 1).4-7

Table 1: Participant headache characteristics (n=20).4-7
CGRP: calcitonin gene-related peptide; FOPQ-C: Fear of Pain Questionnaire, Child report; IQR: interquartile range;
mo.: month; mod./sev.: moderate-to-severe; PedMIDAS: Pediatric Migraine Disability Assessment;
PROMIS: Patient-Reported Outcomes Measurement Information System; VLSQ-8: Visual Light Sensitivity Questionnaire-8.
Light exposure patterns were delayed on the weekends compared to weekdays and were consistent with reported sleep and wake times. Participants spent an average of 15.1% ± SD 8.0 of daylight hours getting the minimum recommended light exposure, while they were more consistently under the maximum light levels recommended 3 hours prior to bed (78.1% ± 20.8 of the time), and at night (99.1% ± 2.9 of the time). Youth whose light exposure was delayed to later in the day reported a greater number of any headache days per month (Spearman correlation coefficient: 0.66; p=0.002) and bad headache days per month (Spearman correlation coefficient: 0.60; p=0.005). The authors also evaluated the effects of weather and daylight length on daily light exposure: days with precipitation, but not colder weather or shorter daylight length, was associated with decreased light exposure.
CONCLUSION
The authors’ exploratory data indicate that youth with migraine get low levels of daylight exposure. Participants in this study spent an average of 1.6 hours a day at or above recommended daylight levels, which was less than half that of a cohort of healthy adults in a similar study done in Manchester, UK.8 While case control comparison is needed to account for other confounding factors (e.g., geography, age, season), the authors’ findings indicate that this is an important direction for future research. Additionally, the authors’ results indicate that delayed daily light exposure should be explored as a potentially modifiable contributor to migraine burden. For more details on this study, please see the publication.2,9



