Mountain Climbers Who Have Had LASIK Should Be Aware of Possible Changes in Vision

Lack of oxygen, often experienced by climbers at high altitudes, causes a temporary change in vision in people who have undergone the LASIK refractive surgery procedure. This is the conclusion of a study in the March 2001 issue of Ophthalmology, the clinical journal of the American Academy of Ophthalmology.

The effect of lack of oxygen at high altitudes on people who have had LASIK is the opposite from the effect on people who have had radial keratotomy (RK), an earlier type of refractive surgery. "RK patients have a shift towards farsightedness, which makes their near vision poor, as happened in the 1996 Mount Everest mountain-climbing disaster. Study results indicate that LASIK patients may develop a shift that would cause their distance vision to become blurry. If distant vision becomes blurred at high altitudes, it may make it difficult to navigate over long distances."

The authors also cite a previous study that shows no change in vision from lack of oxygen in people who have had PRK, another type of laser vision correction that does not require incisions in the cornea.

The current study used an airtight goggle system over a two-hour period to create a lack of oxygen in one eye and a normal oxygen environment in the other eye of 20 people who had had LASIK for nearsightedness and 20 people who had not had previous eye surgery. This amount of exposure to an oxygen-free environment did not correspond to a specific altitude, but it did cause a significant increase in corneal thickness.

In a previous case report published in Ophthalmology (December 2000), Dr. White and Thomas H. Mader, M.D., a co-author of this study, described the case of a mountain climber in Peru who had had LASIK in both eyes who experienced noticeable nearsightedness after spending two nights at 18,000 feet. His vision cleared when he returned to 10,000 feet. Dr. Nelson explains that this and similar reports indicate that significant changes in vision among climbers who have had LASIK seem to occur only over an extended period of time at very high altitudes. "It's a metabolic effect," he said, "the eye gets starved for oxygen even if the climber is breathing oxygen from a tank. The cornea gets part of its oxygen from the external environment."