Certain demographic and physical indicators, such as age and body mass index (BMI), can have an influence on myopia development in adolescents.
Study Design
This retrospective case control study analyzed 1999–2008 National Health and Nutrition Examination Survey (NHANES) data (5 survey cycles) to evaluate potential associations of myopia with age, race, weight, and increased BMI. Information from 9008 adolescents (age 12–19 years) with myopia was included.
Outcomes
The overall rate of myopia in the study population was 30.6%. Older age, Hispanic ethnicity, and greater weight/BMI were associated with increased risk of myopia occurrence. Taller height was a modest risk factor for the degree of myopia.
Limitations
The study relied on NHANES data from 1999–2008, which are now 16–25 years old. Since the incidence of myopia has increased since then and there are many reasons for this increase which were not as prevalent during that time period (e.g., increased tablet/smartphone use, especially in school), the data may not be as relevant now. As well, the study did not examine some NHANES physical indicators which may influence myopia, such as oral health and diet behavior. Finally, the study was limited by the inclusion of only adolescents and not younger children, in which myopia tends to progress the fastest.
Clinical Significance
The causality between weight/BMI and myopia noted in this study is interesting, and could relate to reduced physical activity and other environmental factors. However, the study did not assess behavioral habits. Myopia development and progression is complex and involves multiple factors, both genetic and environmental, that together may all work to regulate axial length and, ultimately, change in refractive error. Additional studies with diverse populations are needed to better understand myopia development and progression.
Financial Disclosures: Dr. Brenda Bohnsack discloses no financial relationships.