A study recently published in Translational Vision Science & Technology evaluated the association between physical activity in elementary school students and the risk of myopia.
Give me some background first.
As one of the most common refractive disorders, myopia has been predicted to affect nearly 5 billion people by 2050.
Even further: Studies have displayed the fastest rates of myopia occurring between ages 6 and 12.
And the risk factors associated with diagnosis?
While a direct cause for myopia is unknown, certain risk factors are speculated to be related:
- Education
- Lifestyle changes such as reduced physical activity
- Reduced outdoor time
- More close-up work
- Genetic factors
The goal with this study: Researchers evaluated if the lifestyle change of physical activity displayed a relationship with childhood myopia prevalence.
Now, talk about the study.
The cross-sectional study was conducted from August to October in 2022, and involved students or their parents/guardians completing self-administered questionnaires.
Who was included in the study?
Data came from the Tianjin Child and Adolescent Research of Eye, where cluster sampling was utilized to pull a randomized selection of students from nine elementary schools.
This research included a total of 2,976 participants (1,408 boys and 1,568 girls); all participants were between 6-12 years of age.
What were the outcome measures?
Visual acuity testing and noncycloplegic autorefraction were administered.
The questionnaire: Participants completed the Physical Activity Questionnaire for Children (PAQ-C).
The PAQ-C is a seven-day recall questionnaire that assesses participation in different physical activities, at school, during evenings, and weekends.
Findings?
Following statistical analysis, investigators identified that 1,575 of the participants had myopia, a prevalence of 52.92%.
The students were then divided into two groups: the myopia group and nonmyopia group.
There were significant differences between the two groups in terms of:
- Age
- Sex
- School region
- UCVA
- SE
- Nearly all dimensions of physical activity (all P < 0.05)
Tell me more.
After a strata was applied to physical activity, myopia prevalence was found to significantly decrease with increasing physical activity level (P < 0.001).
In addition, higher prevalence of myopia was identified among female students (P = 0.002).
The study authors suggested this may be due to “biological factors, outdoor activity time, and a large quantity of near-vision work.”
Expert opinion?
Per the authors: “Physical activity was inversely associated with the risk of myopia.”
They note that this suggests a protective effect of physical activity on the development and progression of myopia in children aged 6 to 12 years.
However, they also stated that, “The exact mechanisms for the association remain elusive.”
Limitations?
Due to the cross-sectional nature of the study, judgements on causality could not be made. In addition, self-administered questionnaires introduced more subjective measures.
The authors also mentioned limitations in the risk factors that were evaluated, but maintained that the large sample size and adjustment for confounding variables were a key strength.
Take home.
Ultimately, the authors suggested that taking part in physical activity may be an effective measure to reduce the prevalence of myopia for pediatric patients.
They concluded: “Future longitudinal study is needed to evaluate the progression of myopia in school-aged children and to develop intervention strategies to prevent or slow down the progression of myopia.”