Monovision contact lens use in the aviation environment: a report of a contact lens-related aircraft accident.
BACKGROUND
The use of contact lenses to satisfy the distance visual acuity requirements for obtaining a civil airman medical certificate has been permitted since 1976. According to the Federal Aviation Administrations Guide for Aviation Medical Examiners, the use of monovision contact lenses is not considered acceptable for aviation duties.


METHODS
A report is presented using information from a National Transportation Safety Board (NTSB) aircraft report (NTSB/AAR-97/03) of a nonfatal accident on a scheduled airline flight. Past studies on the use of contact lenses in the aviation environment are reviewed.


RESULTS
On October 19, 1996, a McDonnell Douglas MD-88 aircraft, Delta Airlines Flight 554, was substantially damaged in an undershoot approach while landing at LaGuardia Airport, Flushing, New York. The approach, with less than favorable weather conditions, was over water to Runway 13 and the flight crew transitioned to visual references just above the decision height. During continued descent, the plane struck an approach light structure and the end of the runway deck, shearing off the main landing gear and sliding 2,700 feet down the runway.


CONCLUSIONS
The NTSB determined that the probable cause of this accident was the inability of the pilot to overcome his misperception of the airplane's position relative to the runway, due to the use of monovision contact lenses. The adverse effects of wearing contact lenses in the aviation environment are discussed.
Nakagawara
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Federal Aviation Administration--Civil Aeromedical Institute, Oklahoma City, Oklahoma 73125, USA.
Véronneau
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D000060:Accidents, Aviation; D000328:Adult; D000337:Aerospace Medicine; D000401:Aircraft; D002568:Certification; D003261:Contact Lenses / Q000009:adverse effects*; D003657:Decision Making; D003867:Depth Perception; D006801:Humans; D008297:Male; D009949:Orientation; D010468:Perceptual Disorders / Q000209:etiology*