A study that employed wearable sensors and was conducted during the COVID-19 pandemic conditions confirms a link between behaviors and refractive error pathogenesis in childhood myopia. Objective assessment using these devices confirms previous research that shows differing behaviors are associated with myopia, according to the cross-sectional study published in Optometry and Vision Science.

Researchers included 40 children (mean age 14.6±0.4 years, range 10-18 years) in the study, 25 with myopia and 15 without. Participants were asked to wear 2 monitoring technologies — a range-finding device mounted on the right temple of spectacle frames with an infrared tracking beam to measure viewing distance and ambient illuminance, and a wrist-worn actigraph device that records ambient illuminance,  physical activity, and sleep duration — to provide more thorough insight into refractive error pathogenesis.

Participants wore the devices between December 2020 and May 2021, a time when  95% were attending virtual schooling. Researchers found extreme electronic device use (12.0±0.7 hours per day) and sleep duration (8.2±0.2 hours per night) were similar between participants with and without myopia (P >.05 for both). However, those with myopia spent more time performing near and intermediate viewing tasks than those without myopia (P =.008). They also had higher diopter hours (9.4±0.4 vs 7.6±0.5 hours, P =.03).           

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Furthermore, daily light exposure and time outdoors were significantly lower in patients with myopia (P <.05 for both). Participants with myopia were exposed to approximately half as much bright outdoor light as the children without myopia — a behavioral difference substantiating previous findings. Both groups showed “surprisingly” low daylight exposure, according to the researchers — perhaps a sign of the pandemic times in which this study was conducted. Time outdoors averaged 24 minutes on weekdays and 54 minutes on weekend days. Decreased light exposure for children who already have a myopia diagnosis may influence myopic progression. Similarly, extremely low light exposure in patients without myopia may increase myopia prevalence in the future.

While reviews report that extensive use of electronic devices could be myopiogenic, the researchers note that inferences cannot be drawn about the causal relationship between electronic device use, near work, and diminished outdoor time on the onset or progression of myopia

Observations show extensive computer use in tandem with decreased outdoor time and diminished physical activity — factors that may influence potential changes in children’s refractive status and long-term health. The methodology and findings strongly suggest the need for longitudinal studies to investigate these differences in behavioral factors between refractive error groups and their potential role in illuminating influences that contribute to myopia and general wellbeing.

“The effects of extensive computer use with decreased outdoor time and lower level of physical activity may pose changes on long-term general health, in addition to potential changes in children’s refractive status,” according to the researchers. “Longitudinal studies investigating these behavioral factors will shed light on their role in myopia and in overall health.”

Limitations include the study’s relatively small sample size, self-reported refractive status and quantification of electronic device use, and limited range of patient ethnicities.


Bhandari K, Shukla D, Mirhajianmoghadam H, Ostrin LA. Objective measures of near viewing and light exposure in schoolchildren during COVID-19. Optom Vis Sci. 2022;99(3):241–252. doi:10.1097/OPX.0000000000001871