Eyes, Right

Editorial, by Jon L. Jordan, MD, JD

Good vision and healthy eyes-including good depth perception—are extremely important in aviation. This has been recognized since the beginning of manned flight, and our earliest medical standards emphasized this factor by "looking" for perfect vision in would-be pilots.

Both military and commercial aviation interests rejected applicants for pilot positions if these applicants required visual correction or had more than very minimal refractive error. Only more recently has there been some relaxation of these requirements, at least in the civilian sector.

The Federal Aviation Administration's (FAA's) medical standards were changed in September 1996 to permit airman medical certification, regardless of uncorrected distance visual acuity, if each eye is corrected to 20/20 (first- and second-class certification) or 20/40 (third-class certification). Certification is contingent on the person wearing the required corrective lenses while exercising the privileges of an airman certificate. The changes were based, however, on many years of certification experience that demonstrated no excess risk with the use of proper visual correction.

Not everyone has agreed with this change or with FAA's adoption of a less stringent, but job related color vision standard. We believe, however, that the current standards are appropriate, but recognize that vigilance regarding accident experience is necessary.

Monovision Pilots

Of immediate concern to the FAA is the increasing use of "monovision" contact lenses or of refractive surgery that leaves the subject with one eye corrected for distance and the other corrected for near vision. This may significantly alter depth perception. The subject is essentially monocular, using only one eye at a time, yet without the long-term adaptation of someone who actually is anatomically monocular. We believe this poses a serious safety risk to airmen (see NTSB story in this issue).

For years, the FAA has noted that this practice is unacceptable for airmen. Unfortunately, many airmen seem to be unaware of this position. In fact, they may wear conventional spectacles or acceptable contact lenses to scheduled medical examinations, yet use monovision lenses while flying. Aviation Medical Examiners must counsel against this practice and ensure that their ophthalmologist and optometrist colleagues also are informed of this potentially dangerous action.

International Vision Research

The Office of Aerospace Medicine, under the auspices of the International Civil Aviation Organization, will participate this summer in a multinational working group that will study vision issues. Included in the study will be consideration of the various methodologies of refractive surgery, such as photorefractive keratectomy (PRK).

The use of these procedures among pilots and air traffic control specialists appears to be rapidly increasing, even though there is concern within the aeromedical community about the suitability of the procedures in aviation and about potentially adverse outcomes. While our experience so far has been good, we look forward to gaining a more comprehensive assessment.

JLJ