Summer babies, more myopia?

Are summer babies more near-sighted? A recent study from Israel suggests this.

Over 250,000 conscripts to the Israeli armed-forces, aged 16-22, were examined. 2.4% were found to be extremely myopic (more than six diopters of myopia). These subjects were 25% more likely to have been born in June or July than in December or January.

While this statistical correlation is modest, it suggests that increased exposure to light during infancy may have a role in developing myopia. A study a few years back about use of nightlights and myopia progression, which I discounted due to the possibility of confounding variables, now may have more credence.