Study finds link between myopia, vitamin D status

ORLANDO, Fla. — In a study involving 946 young adults, researchers found that increasing serum concentration of vitamin D was associated with a decreasing prevalence of myopia and that a higher vitamin D status decreased the risk of myopia.

Alex W. Hewitt, BMedSci(Hons), MBBS, PhD, of the Centre for Eye Research in Melbourne, Australia, reported here at the Association for Research in Vision and Ophthalmology meeting results of a 20-year follow-up of the Western Australian Pregnancy Cohort (Raine) Study.

Hewitt and colleagues found that 220 subjects in the group were myopic. Myopia was considered as a mean spherical equivalent of at least –0.5 D.

Patients underwent cycloplegic autorefraction and conjunctival ultraviolet autofluorescence to measure UV light in the eye, Hewitt said. Circulating vitamin D levels were measured by serum 25(OH)D concentration. Data were deseasonalized, he noted.

“Usual players were found to be factors in the myopia cohort: Asian ancestry, ongoing education, family history of myopia, outdoor activity being less common,” he said. “An objective measure of conjunctival UV autofluorescence was found to be smaller in those who were myopic, and we found an association between vitamin status and myopia.”

He referred to these associations as “modest but statistically significant.”

The relationship between vitamin D and myopia was first evaluated in 2011, Hewitt said.

“Supporting earlier work, we found a weak positive relationship between conjunctival autofluorescence and vitamin D levels and a weak inverse relationship between refractive error and vitamin D levels,” he said.

The authors noted in the abstract that it still must be determined whether higher vitamin D serum concentration is protective against myopia or merely indicates sun exposure.

Disclosure: Hewitt and colleagues have no relevant financial disclosures.