Washington, Mar 4 : A new study has found that people with a certain low level of tear production are more likely to develop chronic dry eye syndrome after LASIK (laser-assisted in situ keratomileusis), laser refractive surgery to correct near- and far-sightedness, than those with more plentiful tears.
Researchers at Schepens Eye Research Institute believe that their findings may offer reliable pre-screening criteria for ophthalmologists and patients.
"These findings should help ophthalmologists determine if pretreatment is necessary before surgery or if surgery is appropriate at all for an individual," said Dr. Darlene Dartt, director of the Military Vision Research Program at Schepens Eye Research Institute and the principal investigator of the study.
LASIK surgery uses small laser cuts to reshape the surface of the cornea, eliminating far-sightedness or near-sightedness, and the need for glasses or contacts.
In past few years years, thousands of military personnel have gone for LASIK surgery because it can help them see better, identify objects and people in the field more quickly and also relieves them of the worry about lost or damaged glasses.
Usually, the surgery leads to dry eye syndrome directly after surgery, but the condition resolves within a few months.
However, 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 following surgery.
The researchers wanted to find a way to pre-screen for the chronic condition so that surgeons could prepare patients in advance with preventative artificial tears or opt against surgery for some patients.
Dartt and her team tested the eyes of 24 patients about to undergo LASIK at the Massachusetts Eye and Ear Infirmary.
The patients were given a series of tests, including the Schirmer test with and without anaesthesia, before and after surgery.
The Schirmer test uses a piece of paper on the corneal surface to measure the amount of tears an eye is producing. Patients also filled out a dry eye questionnaire indicating their experience with dry eyes pre- and post-operatively.
The researchers found that if a patient had a presurgical tear production value greater than 20 mm of wetting of the Schrimer strip in 5 minutes, they were not likely to develop chronic dry eye syndrome.
Patients who produced less tears were more likely to develop long-term dry eye syndrome.
The study is published in the January issue of Investigative Ophthalmology and Vision Science.