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A review of the world literature shows that about one-third of patients who are undergoing LASIK already suffer from dry eye, and the proportion affected after surgery is similar. In most cases, however, dry eye does not appear to affect postoperative vision and satisfaction outcomes adversely. Identification of patients at risk and pre-treating may reduce the postoperative incidence of dry eye.
As part of a project undertaken by the Joint LASIK Task Force, a collaboration of representatives from the National Eye Institute, the American Society of Cataract and Refractive Surgery, and the AAO, Dr. Donnenfeld, assisted by several other participants, undertook a comprehensive search and review of the world literature pertaining to dry eye and LASIK. The most important finding was that dry eye was extremely common before and after surgery, said Dr. Donnenfeld, clinical professor of ophthalmology, New York University, and founding partner, Ophthalmic Consultants of Long Island.
Dry eye was present in 32% of patients before LASIK and affected 35% of patients after their laser procedure. Across various studies, dry eye was reported both to worsen and to improve after LASIK, although in general, patients with pre-existing dry eye were at greater risk for experiencing dry eye after surgery.
"These findings reinforce that LASIK surgeons need to be vigilant in identifying surgical candidates with dry eye. This will allow appropriate counseling, pre-treatment, and exclusion of some patients to achieve overall better outcomes," Dr. Donnenfeld said.
The literature search was conducted using the keywords LASIK, laser vision correction, and laser in situ keratomileusis, and it identified 2,915 articles. Abstract review resulted in identification of 1,581 articles that warranted more in-depth review. Of those, 309 articles were determined to meet criteria for Level I (well-designed, well-conducted, randomized controlled trials) or Level II (well-designed case-control or cohort studies) evidence and were considered further. A total of 113 articles were identified as pertinent to the issue of dry eye, but only 46 of the papers included data able to be reviewed. The 46 studies were published in 13 journals, conducted in 15 countries, and included more than 32,000 eyes. Follow-up after LASIK ranged from 1 to 6 months, he said.
Data reported in the studies also indicated that severe dry eye after LASIK was rare. In addition, the published articles showed that post-LASIK dry eye tended to resolve within 6 weeks after surgery and often within 2 to 4 weeks.
One study from Australia reported that preoperative dry eye was the strongest predictor of dry eye after LASIK. In addition, this study showed that higher attempted refractive correction was a risk factor.
"Other issues identified as affecting dry eye after LASIK include the depth of ablation, hinge location, and goblet cell density. In addition, there is evidence that modern thin-flap LASIK is associated with a reduced incidence of dry eye," Dr. Donnenfeld said.
Better treatment of dry eye disease, both pre- and postoperatively, is improving outcomes, he said. These advances include better artificial tears, immunomodulation with topical cyclosporine A emulsion (Restasis, Allergan), use of oral nutritional supplements, and identification and treatment of lid margin disease.
Dr. Donnenfeld reminded his colleagues that dry eye is the leading medical reason that patients seek attention from an eye-care professional. According to one estimate, 55 million Americans suffer from dry eye disease, and the symptoms, which can include burning, irritation, foreign body sensation, and fluctuating vision, can have an effect on quality of life and the ability to perform daily tasks.