The incidence of myopia in the Israel Air Force rated population: a 10-year prospective study.

It is important to define the risk in pilots of becoming myopic in order to determine the need for yearly screening, and to predict pilot eligibility in environments where the use of corrective lenses may present problems. We conducted a prospective study of 1400 air force personnel followed for 10 years, who could be divided into three major groups; those with 20/20 vision in both eyes, those with 20/25 in one eye only and whose vision was 20/20 using both eyes together, and those who were accepted despite the fact that they required corrective lenses. Over the 10-year period, 23.1% of those with 20/25 visual acuity in one eye needed corrective lenses, significantly more than the 7.4% observed in those with 20/20 vision in both eyes (relative risk 3.1, 95% confidence interval 2.2-4.3, p less than 0.0000). The prevalence of corrective lenses increased until age 26. We conclude that 7.4% of pilots will become myopic over a 10-year period if accepted with 20/20 vision in both eyes. The risk, however, is much higher in those with incipient growth myopia starting in one eye at entry. Therefore, the annual screening of visual acuity in air force personnel is essential.