Sleep Patterns and Myopia Among School-Aged Children in Singapore

Abstract

PurposeTo evaluate the associations of sleep factors with myopia, spherical equivalent (SE), and axial length (AL) in elementary school-aged children from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort.MethodsThis cross-sectional study included multi-ethnic children who participated in the GUSTO prospective birth cohort and were delivered in two major tertiary hospitals in Singapore (2009–2010). Sleep factors and myopia outcomes were assessed at the 8- and 9-year study visits, respectively. Parent-reported sleep quality was assessed with the Children's Sleep Habits Questionnaire (CSHQ) total scores. Additionally, each child's sleep duration, timing (bedtime; waketime), and the consistency of sleep duration or timing (i.e., the difference between weekends and weekdays) were parent-reported. Outcomes included cycloplegic SE, myopia (SE ≤ −0.5 D) and AL. Eye measurements from both eyes were included in the analyses. Multivariable linear or logistic regression with Generalized Estimating Equations were used to account for the correlation between paired eyes and confounders in the associations of sleep factors at age 8 and myopia at age 9.ResultsA total of 572 multi-ethnic children (49.5% boys; 56.1% Chinese) aged 9 years were included in the analyses. Overall, 37.3% of eyes were myopic. Children reported a mean total CSHQ score of 46 [standard deviation (SD) = 6]. The mean duration of sleep was 9.2 (SD = 1.0) hours per day (h/day), with 59.9% of children reporting sufficient sleep (≥9 h/day) based on guidelines recommended by the National Sleep Foundation, USA. The mean bedtime and wake time were 22:00 (SD = 00:53) and 07:08 (SD = 00:55), respectively. In multivariable regression models, total CSHQ scores, the duration of sleep, bedtime and wake time were not significantly associated with myopia, SE, or AL (p ≥ 0.05 for all), adjusting for gender, ethnicity, time outdoors, near-work, parental myopia, maternal education levels (and additionally the child's height when the outcome was AL). Similarly, the consistency of both the duration and timing of sleep (across weekends and weekdays) were not significantly associated with myopia, SE, or AL (p ≥ 0.05 for all).ConclusionIn this cross-sectional study, sleep quality, duration, timing, and the consistency of specific sleep factors were not independently associated with myopia, SE, or AL among elementary school-aged children in Singapore. Large longitudinal studies are warranted to corroborate these results.

Association between sleep duration and myopia among Chinese children during the COVID-19 pandemic: A cross-sectional study

“…Similar to Singapore (GUSTO) study showed no association between sleep duration and myopia, SE, or AL among 376 3-year-old children ( 24 ). Recently, Li et al also found no independent correlation between sleep duration and myopia, SE, or AL in the same GUSTO study in 572 9-year-old Singaporean children ( 15 ). Moreover, the study by Liu et al of 4,982 Chinese children aged 6–9 years revealed that late bedtime but not sleep duration related to 2-year myopia onset ( 25 ).…”

“…The study on Japanese children aged 10–19 indicated that children with high myopia had the poorest sleep quality and shortest sleep duration than children with emmetropia ( 12 ). In contrast, sleep duration was unrelated to myopia in studies of Chinese and Singaporean children ( 13 – 15 ). These inconsistent results complicate the relationship between sleep and myopia.…”

“…Second, sleep data did not include bedtime, wake time, and sleep quality. However, prior studies could not provide sufficient evidence to support the association of sleep quality and bedtime with myopia ( 15 , 42 , 43 ). Third, the study did not include screen time in children.…”

Association between sleep duration, sleep quality, bedtime and myopia: A systematic review and meta‐analysis

“…A total of 1279 studies were identified using the search strategies. Thirty‐one studies 10–12,16–43 were included in the final analysis after removing duplicates, screening titles and abstracts, and reading the full texts of possible eligible studies (Figure 1). Twenty‐eight studies were conducted in China and the remaining studies were conducted in Singapore and Korea.…”

Myopia and hyperopia are associated with opposite chronotypes in a sample of 71,016 individuals

“…Various sleep parameters, particularly bedtime, sleep quality, and duration, have been investigated in myopia but, thus far, have yielded mixed results. Several studies have found that children with myopia sleep later than children without myopia [16][17][18][19] , while some have found no association [20][21][22][23] . Myopia has been associated with lower sleep quality in some studies 16,24 , while no associations have been found in others 25 .…”