Darlene A. Dartt, Ph.D.

Question: I have read that many soldiers have LASIK surgery (laser-assisted in situ keratomileusis) on their eyes before going to combat zones in the middle east, and that some develop severe dry eye syndrome after they are deployed. Is there something that can prevent the complications for these servicemen and women?

Answer: Thousands of soldiers have LASIK surgery to correct far- and near-sightedness
before they go overseas.Whilemany civilians choose this surgery for cosmetic reasons, those in the armed forces opt for the surgery because it can help them see better and identify objects and people in the field more quickly, and because it eliminates the worry and hassle of glasses or contacts. These advantages can be lifesaving on the battlefield.

As you know, LASIK surgery uses small laser cuts to reshape the surface of the cornea (the clear tissue window on the surface of the eye). Usually, LASIK causes some dry eye syndrome directly after surgery, but the condition resolves within a few months. Dry eye syndrome occurs when the mechanism that produces tears, called the tear film, does not function well enough to lubricate the eye. In a small number of cases, the dry eye condition following LASIK can become chronic and impact functioning of both civilian and military individuals for as long as nine months after surgery.

While painful in civilian life, dry eye syndrome could become life threatening under combat conditions.

As part of our commitment to our military research program, we decided to investigate what makes a person more likely to develop this chronic eye syndrome.

We discovered that people who had less than normal tear production before LASIK surgery were more likely to develop the chronic dry eye condition after surgery. At the same time, we developed a reliable prescreening test and criteria for patients and ophthalmologists to consider before surgery.

To do this, we evaluated 24 patients who were about to undergo LASIK at the Massachusetts Eye and Ear Infirmary. The patients were given a series of evaluations, including the Schirmer test with and without anesthesia, before and after surgery. Using a piece of filter paper on the corneal surface, the Schirmer test measures the amount of tears an eye is producing. Study subjects also filled out a dry eye questionnaire, indicating their experience with dry eyes pre- and post-operatively. The team discovered that if a patient had apresurgical tear production value greater than 20 mm of wetting of the Schirmer strip in 5 minutes, they were not likely to develop chronic dry eye syndrome. Patients who produced fewer tears were more likely to develop long-term dry eye syndrome.

We believe that these findings should help ophthalmologists determine if pretreatment, which can include a regimen of artificial tears over a given period of time, is necessary before surgery—or if surgery is appropriate at all for an individual.

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