Exploring the Effects of Age at Menarche and Pregnancy on Myopia.

Purpose: Associations between age at menarche and myopia have been observed in studies that included older women. Furthermore, pregnancy-related hormone surges in young women are associated with short-term changes in refractive error, although the long-term effects are less known. This study explored associations of age at menarche and parity with refractive error and ocular biometry in young women, and the relationship between age at menarche and refractive error in middle-aged adults for comparison.

Methods: Community-based young women underwent eye examinations at 20 and 28 years old. Information on age at menarche and parity were collected prospectively. The older cohort underwent an eye examination and information on age at menarche was self-reported retrospectively. Cross-sectional associations between age at menarche and myopia were explored in both cohorts. Associations between parity and 8-year longitudinal change in refractive error measures were explored in the young cohort.

Results: The cross-sectional analyses comprised 429 young (age 18-22) and 1,818 older (age 46-69) women. No associations were found between age at menarche and myopia or ocular biometry measures in either cohort. The longitudinal analysis (n = 269 women) revealed that for each pregnancy carried to full term, there rate of lens thickening increased by 0.004 mm/year (95% CI = 0.002-0.007). No other associations between parity and refractive error or ocular biometry were found.

Conclusion: There is no association between age at menarche and myopia or its related measures. While pregnancy was associated with thicker lens in the long term, there is no lasting effect on refractive error.