[Relationship between birth month and ocular refraction noted during eye disease checkups for three-and-a-half-year-old children in Japan].

PURPOSE

To examine the relationship between birth month and ocular refraction in three-and-a-half-year-old children.

METHODS

A total of 487 children were examined during eye disease checkups performed in three-anda-half-year-old children in Kishiwada, Japan. Using left eye data, mean refractive values were calculated and graphically analyzed for each birth month. The relationship between refraction and birth season was evaluated by ANOVA.

RESULTS

A slight shift in the mean refraction to the hyperopic side was found for subjects born in September and October. The mean refractions +/- SE were: -0.058 +/- 0.057 D in spring (n = 118), -0.001 0.052D in summer (n = 124), +0.133 +/- 0.064D in autumn (n = 112), and -0.143 +/- 0.055 D in winter (n = 111). Comparisons of refraction for each birth season proved to be significantly different, with subjects born in autumn found to be more hyperopic (p = 0.008).

CONCLUSION

A relationship between refraction and birth season was found in three-and-a-half-year-old children, with children born in the autumn tending to be more hyperopic.