Hyperopic thermal keratoplasty procedure in a civilian air traffic controller.
Hyperopic thermal keratoplasty (HTK), also referred to as radial thermokeratoplasty, is one of several refractive surgery procedures in use to correct significant visual acuity problems. The current procedure was developed in the farmer Soviet Union, and was first performed in the U.S. in the early 1980's. The thermocoagulating unit used for the surgery is still considered an experimental device by the Food and Drug Administration, and as such requires a device exemption permit from that Agency for its use. The unit is used to coagulate corneal protein, which alters the shape of the cornea and hence its refractive power. No well-controlled series of patients followed over time exists to conclusively state the pros and cons of the procedure. Excimer laser surgery has been recently used as a substitute for the thermocoagulator, but experience is also limited. Lasers, nevertheless, show great promise for use in this procedure. While HTK has been shown to correct hyperopia, significant sequelae have been documented with the procedure; they have included unstable visual acuity, under- and overcorrection of acuity, damage to the cornea, and scarring. These sequelae may present a problem for individuals involved in aviation, where issues of visual acuity are critical. It is important to identify such individuals and monitor their vision status carefully prior to return to safety related duties.
Federal Aviation Administration, Office of Aviation Medicine, Southwest Region Medical Division, Fort Worth, TX 76193-0300.
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Salazar
D000328:Adult; D000337:Aerospace Medicine; D016039:Corneal Transplantation / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008297:Male; D014792:Visual Acuity