Daily light exposure habits of youth with migraine: a prospective exploratory study

Photophobia is a common symptom in youth with migraine, but it is unknown if this leads to light-avoidant behavior, and its effect on migraine disease burden. We conducted an exploratory study measuring light exposure using wearable light logger pendants in 20 adolescents with migraine (ages 15-21) over one week. On average, participants received recommended light exposure during only 15.1% during the day ( $\ge$ 250 lux melanopic equivalent daytime illuminance from 7:00-17:00) but were generally within recommended light levels in the evening (78.1% from 20:00-23:00 at $\le$ 10 lux), and at night (99.1% from 0:00-6:00 at $\le$ 1 lux). We observed differences in light exposure on weekdays versus weekends. Individual variation in circadian delay of light exposure was strongly correlated with the number of headache days per month (Rho = 0.66, p = 0.002). Measuring daily light exposure is feasible in pediatric populations with photophobia and warrants further study.