Children in Tokyo Have a Long Sustained Axial Length from Age 3 Years: The Tokyo Myopia Study

Abstract

Background: myopia prevalence is high among Japanese schoolchildren, but the underlying causes are unclear. Objective: To examine the distributions of ocular biometry and refraction and their associations with lifestyle variables among Japanese schoolchildren. Methods: This cross-sectional school-based study included 2140 children aged 3–14 years in Tokyo, Japan, and evaluated the distributions under non-cycloplegic conditions and the associated environmental factors. Results: The prevalence of spherical equivalent (SE) ≤−0.75 diopter among preschoolers (aged 3–6 years), elementary school students (aged 6–11 years), and junior high school students (aged 12–14 years) was 49.7%, 72.4%, and 87.7%, respectively. Multiple linear regression analyses showed that the time spent using digital devices was associated positively with lens thickness (β = 0.010; p < 0.050) but not SE, axial length, or vitreous chamber depth. The time spent reading was associated negatively with lens thickness (β = −0.012; p < 0.050), SE (β = −0.152; p < 0.010), axial length (β = 0.110; p < 0.001), and vitreous chamber depth (β = 0.110; p < 0.001). Conclusions: The data indicated that almost half of preschoolers may be myopic. The association with the lens thickness differed depending on the type of near work performed.

The Incidence and Severity of Myopia in the Population of Medical Students and Its Dependence on Various Demographic Factors and Vision Hygiene Habits

“…In each procedure, the autorefractometer was held at the recommended height of the participant’s eyes. The methodology was similar to the study performed by Maruyama et al [ 24 ]. The procedure was applied in an environment recommended by the producer- in a darkened room from a distance of 1 m. The testing of the refractive defect was conducted without pharmacological dilation of the pupil, as described by the producer of the device.…”