Kindergarten type, preschool educational environment, and screening-defined myopia in Japanese preschool children.

PURPOSE: To evaluate the association between kindergarten type (public vs private) and screening-defined childhood myopia among Japanese preschool children, and to explore potential behavioral correlates of this association.

STUDY

DESIGN

Cross-sectional study.

METHODS

We analyzed data from 153 preschool children aged 3-6 years attending public (n=115) or private (n=38) kindergartens in urban Kawasaki City, Japan. Myopia was defined using non-cycloplegic refraction combined with age-specific visual acuity thresholds to reduce overestimation. Kindergarten type was the primary exposure. Prespecified covariates were age, sex, and parental myopia. Exploratory behavioral variables included weekday reading/writing time, screen time, and exercise time at kindergarten. Because only eight children had screening-defined myopia, penalized logistic regression was used.

RESULTS

Myopia prevalence was 1.7% (2/115) in public kindergarten attendees and 15.8% (6/38) in private kindergarten attendees. After adjustment for age and parental myopia, private kindergarten attendance was associated with higher odds of screening-defined myopia (odds ratio [OR], 6.50; 95% confidence interval [CI], 1.54-36.86). This association remained consistent in sensitivity analyses additionally adjusting for sex (OR, 7.93; 95% CI, 1.80-46.89) and recoding parental myopia as binary (OR, 8.95; 95% CI, 2.04-53.38). Exploratory analyses showed that private kindergarten attendance was associated with longer weekday reading/writing time and shorter exercise time at kindergarten, but not clearly with screen time.

CONCLUSION

Private kindergarten attendance was associated with a higher prevalence of screening-defined myopia in this sample of Japanese preschool children. These findings suggest that differences in preschool educational environment and daily visual behavior may contribute to early myopia risk. Further multicenter longitudinal studies are warranted to confirm these findings and to identify modifiable environmental factors that may support future strategies for the early prevention of childhood myopia.