Sleep in Myopic and Non-Myopic Children

Abstract

To examine differences in sleep between myopic and non-myopic children. Methods: Objective measurements of sleep, light exposure, and physical activity were collected from 91 children, aged 10 to 15 years, for two 14-day periods approximately 6 months apart. Sleep parameters were analyzed with respect to refractive error, season, day of the week, age, and sex. Results: Myopic children exhibited differences in sleep duration by day of the week (P < 0.001) and season (P = 0.007). Additionally, myopic children exhibited shorter sleep latency than non-myopic children (P = 0.04). For all children, wake time was later (P < 0.001) and sleep duration was longer (P = 0.03) during the cooler season compared with the warmer season. On weekends, children went to bed later (P < 0.001), woke up later (P < 0.001), and had increased sleep duration (P < 0.001) than on weekdays. Younger children exhibited earlier bedtime (P = 0.005) and wake time (P = 0.01) than older children. Time spent outdoors was positively associated with sleep duration (P = 0.03), and daily physical activity was negatively associated with wake time (P < 0.001). Conclusions: Myopic children tended to have more variable sleep duration and shorter latency than non-myopic children. Sleep patterns were influenced by season, day of the week, age, time outdoors, and activity. Translational Relevance: Myopic children tended to have more variable sleep duration and shorter latency than non-myopic children, which may reflect previously reported differences in environmental and behavioral factors between refractive error groups.

Objective Behavioral Measures in Children before, during, and after the COVID-19 Lockdown in Israel

“…Thus, it is likely that much of reduction in light exposure was due to social distancing restrictions and not available light exposure. In terms of sleep duration, a previous study with Actiwatches found that a small seasonal difference of 11.5 min [35], unlike the current study which did not find a significant difference in sleep duration. Similarly, we hypothesize that the reduced physical activity observed in the current study during pandemic restrictions was not due to an effect of season.…”

“…Each Actiwatch was dispensed for children to wear continuously for two weeks during the pre-pandemic and 10 days during the pandemic and post-restrictions and set to collect data at 1-min epochs. The epoch length was chosen to compare the results to previous studies in children using the Actiwatch Spectrum [18,34,35].…”

“…Since children's physical activity is composed of short bouts, this may have missed some short-duration vigorous activity. Despite these shortcomings, the same parameters were used in this study as in previous studies of light exposure, physical activity, and sleep using the same device (Actiwatch Spectrum) [18,34,35], so as to compare the results. Furthermore, the main finding was the change in behavior at different points of time for the same subject.…”

Objective and Subjective Behavioral Measures in Myopic and Non-Myopic Children During the COVID-19 Pandemic

“…The Actiwatch has been widely used in behavioral and sleep studies in children and adults. 3 , 28 – 30 The device is waterproof for up to 30 minutes and the battery lasts for up to 60 days when fully charged. The Actiwatch was set to average over 1-minute epochs.…”

IMI Risk Factors for Myopia

“…Associations between sleep and myopia have also been reported, but the evidence is quite inconsistent. [208][209][210][211][212][213] A large longitudinal study from Shanghai reported consistent significant associations of going to sleep late with greater myopia prevalence at baseline, incident myopia, and myopic shift in refraction, after adjustment for several variables including age, but did not find that sleep duration was an important factor. 214 The authors noted that going to sleep late was more prevalent in children who lived in urban areas, were older, had more parents with myopia, had better educated parents, tended to wake up late, spent more time reading and on screens, and spent less time outdoors -all characteristics that were also identified as risk factors for myopia.…”