Summer births increase myopia risk

The month in which one is born may increase the likelihood of suffering severe myopia, according to a study published in the April 2008 issue of Ophthalmology.

Yossi Mandel, MD, MHA of Selim and Rachel Benin School of Computer Science and Engineering, Hebrew University of Jerusalem, Israel and colleagues conducted a five-year retrospective, population-based epidemiological study of 276 911 subjects aged 16–22 years to determine the relationship between the length of perinatal light exposure (photoperiod) and severe myopia.

Across all subjects, the incidence of severe myopia was 2.4%. After adjusting for traditional myopia risk factors, the odds ratios for severe myopia were higher for shorter photoperiods (1.24) than for longer photoperiods (1.15–1.33). Severe myopia was found to be least prevalent in subjects born in December/January, and most prevalent in subjects born in June/July.

The researchers concluded that there was a correlation between month of birth and severe myopia; specifically, that those born in summer months have an increased likelihood of becoming a sufferer. The investigators posited that the exposure to light during the perinatal period may impact the eye's development and ability to refract light.