Las Vegas-Post-LASIK dry eye is a common problem even in patients with no preoperative evidence of dry eye. In fact, the prevalence of dry eye in the adult population has been reported to be as high as 70% (under certain conditions). Therefore, all LASIK candidates should be treated as if they might develop the condition, according to a refractive surgery expert.
Dry eye may occur after keratorefractive surgery because of inflammation, surgically induced trauma, or the use of drugs with preservatives. Patients may experience dry eye symptoms due to neurotrophic conditions that develop after flap creation or ablation of the superficial corneal nerve plexus, said Peter J. McDonnell, MD, who spoke during the refractive surgery subspecialty day held in conjunction with the annual meeting of the American Academy of Ophthalmology (AAO) and sponsored by the International Society of Refractive Surgery of the AAO.
"In some cases, dry eye may exist prior to LASIK," said Dr. McDonnell, director of The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore.
Dr. McDonnell referred to a study published in 2006 that indicated the various risk factors associated with post-LASIK dry eye in a myopic population (De Paiva CS. Am J Ophthalmol 2006;141:438-445). Researchers found that patients with greater myopia had an increased risk of developing dry eye postoperatively, and the depth of the treatment contributed to the increased risk.
"However, the study showed that the hinge position-whether it had been nasal or superior-was not a major factor in terms of determining who would develop this problem postoperatively," he said.
In this same study, the incidence of dry eye after LASIK in a myopic population was high, with half experiencing symptoms at 1 week postop. The dry eye symptoms persisted at 1 month in 40% of patients, and at 6 months 24% still had dry eye.
Problems of dry eye are more common after hyperopic LASIK than myopic LASIK, in Dr. McDonnell's personal experience. He attributes this occurrence to older patient age and the need for larger-diameter flaps for the hyperopic ablation.
All LASIK candidates should be evaluated for pre-existing dry eye and, if the condition is found, treated aggressively before undergoing surgery.
"The ocular surface should be as healthy as possible" prior to the procedure, he said.
Although there is no proven method for preventing LASIK-associated dry eye, refractive surgeons can take some prophylactic steps to try to avoid this problem.
"Consider using temporary collagen plugs at the time of surgery and then use frequent unpreserved artificial tears after the procedure," he said.
Topical cyclosporine 0.05% (Restasis, Allergan), the only product approved by the FDA for treating moderate-to-severe dry eye, can be advantageous for LASIK patients who experience postoperative dry eye. In a 2005 report from the Association for Research of Vision and Ophthalmology annual meeting, R. Ursea and colleagues noted that two-thirds of refractive surgery patients had postoperative dry eye and had improved surgical outcomes after topical cyclosporine application. This finding included improved postoperative visual acuity. The report was entitled "The role of Restasis in faster visual acuity recovery after refractive surgery," Dr. McDonnell said.
In the future, refractive surgeons may have other management solutions for dry eye, such as nerve growth factor to restore the nerve plexus more quickly. They may be better able to detect subclinical disease before surgery to warn patients about the risks of dry eye and the need for dry eye prophylaxis and follow-up, he said.