Present status of radial keratotomy myopia surgery: aerospace considerations

Radial keratotomy (RK) is one of several corneal surgery operations recently developed to change the refraction of the eye. RK consists of four to eight deep radial incisions extending from the corneal edge to a small central optical zone, which flattens when the corneal scars heal. This decreases the myopia, or excess corneal dioptric power by 2.00 to 6.00 diopters. The draw-backs of RK for aviators consists of the following problems and side effects: 1) several ocular surgical complications, which may cause loss of vision; 2) glare and dazzle inflight effects; 3) imprecise and unpredictable results; 4) diurnal change of refraction and vision; 5) residual regular and irregular astigmatism; 6) a decrease of best corrected vision; 7) late progressive hyperopia; and 8) greater susceptibility to aggravated ocular trauma. Radial keratotomy presently appears to be fraught with intrinsic hazards and is imprudent and inadvisable for pilots or aircrew, in whom long-term stable, non-fluctuating, asymptomatic, keen vision is required in both bright and dim light.