Longitudinal Outcomes of U.S. Air Force Pilot Applicants With Waivered Astigmatism

Current U.S. Air Force medical standards allow applicants to enter pilot training with up to 1.50 D of astigmatism. However, waivers are considered for individuals with up to 3.00 D of astigmatism. Although typically a benign finding, higher levels of astigmatism may be progressive and can be associated with corneal ectasia (e.g., keratoconus or pellucid marginal degeneration) leading to reduced visual acuity with spectacles and/or soft contact lenses. The goal of this study was to evaluate the long-term outcomes of pilot applicants waivered into training with astigmatism exceeding the aeromedical standard.

Subjects were identified on the basis of their enrollment in the Excessive Astigmatism Management Group maintained by the Aeromedical Consultation Service, Ophthalmology branch at Wright-Patterson Air Force Base, Ohio. Metrics evaluated included refractive status, visual acuity, aeromedical waiver status, safety data, and the development of corneal ectasia.

Seventy-six subjects were tracked for up to 10 years, with an average follow-up period of 5.5 years. Mean astigmatism at initial examination was 1.91 D, although mean astigmatism on the basis of the most recent examination was 2.19 D. Subjects with excessive astigmatism who were waivered into pilot training showed an average increase in astigmatism of slightly less than 0.05 D annually, which equates to a total increase in astigmatism of approximately 0.25 D for the duration of the study. No subjects developed ectasia or were disqualified from flying for vision or refractive reasons. No mishaps were identified with vision being a causative or contributing factor.

This study supports continuation of current Air Force waiver policy, although a longer follow-up period is required to consider modifying the aeromedical standard for astigmatism.