• Association Between Myopia and UVB, Vitamin D Levels, or Genetics of Vitamin D Metabolism

    Written By: Lynda Seminara and selected by Neil M. Bressler, MD

    Journal Highlights

    JAMA Ophthalmology, January 2017

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    Spending time outdoors is known to protect against myopia, but it is not clear whether the primary reason is light intensity, ultraviolet radiation, serum vitamin D concentrations, or other factors. Williams et al. conducted a secondary analysis of the European Eye Study and found that of the factors above, only ultraviolet B (UVB) radiation exposure, particularly during adolescence and early adulthood, was associated with a reduced odds ratio (OR) for myopia.

    Their study cohort (N = 3,168) was selected from a cross-sectional, population-based random sample of individuals 65 years of age and older; 371 participants had myopia, defined as a mean spherical equivalent of –0.75 D or worse. All participants received an eye exam, including refraction; provided a blood sample; and complet­ed a comprehensive questionnaire on demographics, education, and other lifestyle factors. Of particular interest was the amount of time spent outdoors during daylight hours from age 14 years onward.

    Vitamin D serum concentrations were measured using spectrometry and were adjusted by season. Data on vitamin D pathway single nucleotide polymorphisms (SNPs) were available for approximately one-third of the study population. Logistic regression was used to estimate ORs for myopia and UVB exposure, serum vitamin D concentrations, and vitamin D SNPs.

    An increase in UVB exposure in the age groups of 14-19 and 20-29 years was associated with reduced odds for myopia. In keeping with earlier studies, the OR for myopia was significantly higher for the most-educated subset of participants. There was no evidence of a direct link between myopia and serum vitamin D concentrations or the genes involved in vitamin D metabolism. Un­expectedly, very high concentrations of plasma lutein appeared to correlate with reduced odds of myopia, a finding that warrants further investigation.

    The authors concluded that expo­sure to UVB radiation between 14 and 29 years of age is associated with the greatest protection against myopia.

    The original article can be found here.