Incidence of myopia higher than expected

A major US-based study has found that the number of children from a range of ethnic backgrounds found to be myopic is much higher than had previously been thought.

The study, published in this month's Archives of Ophthalmology, followed the refractive progression of over 5,000 children aged 5-16. When using the definition of -0.75D or more myopia in both principal meridians, 16.4 per cent of the children became myopic during the study period.

If researchers used the definition of -0.50D mean sphere or more myopia, 23.4 per cent became myopic. Mean sphere-based definitions yielded more cases of myopia than did definitions based on the refractive error in both principal meridians.