KnowLASIK

Several studies have reported that LASIK surgery results can be affected adversely by warm temperatures and high humidity. One Wake Forest University Baptist Medical Center study showed that an increased number of people required follow-up procedures if the temperature and humidity were not controlled for properly.

This study along with others has demonstrated that environmental factors can affect LASIK outcomes. During the study it was discovered that a 10 percent increase in treatment room humidity meant an additional nine out of every 100 LASIK patients needed an enhancement procedure on a later date. It is believed that the laser could be absorbed by the humidity and therefore has a reduced effect on the patient’s cornea.

The study also found that outdoor temperatures and humidity in the two weeks prior to having LASIK can also influence surgery results. The study showed that the number of eyes requiring an enhancement procedure was zero percent in the winter and as high as fifty percent in September, when outdoor humidity was highest. In less humid months, there was a tendency to overcorrect vision. During humid months, there was a tendency to undercorrect vision. This can be explained by the fact that the laser is influenced by the water vapor in the air between the instrument and the patient’s eyes.

The study, which examined LASIK surgery on 368 eyes of 191 patients, evaluated 12 variables suspected to affect LASIK results. These factors included age, sex, curvature of the cornea, and environmental factors such as room and outdoor temperature and humidity.

An analysis of these variables revealed that indoor humidity had the most impact on whether a person required an enhancement procedure. The findings appear in the current issue of the Journal of Cataract and Refractive Surgery.

Dr. Keith Walter, an assistant professor of ophthalmology and an author of the study stated that “environmental data should play a role in how the [LASIK] equipment is programmed to further refine the visual outcome.” Many LASIK centers have already adjusted their surgical nomogram for days with high humidity. Other centers control carefully for temperature and humidity within the operating room.

“Our study doesn’t mean that consumers should avoid LASIK surgery during the summer. But they should make sure that their physicians compensate for temperature and humidity,” Walter said.

I would advise that any future LASIK patient should carefully consider both the surgeon and the surgical center. If temperature and humidity are not controlled, then it is likely that other factors are also left uncontrolled. Most respectable LASIK centers will control properly for temperature and humidity.