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Patients may experience severe dry eye symptoms following refractive surgery. By 6 months postoperatively, however, the majority of patients are no longer plagued by severe dry eye, according to a prospective, randomized study. More LASIK patients than PRK patients seem to experience severe dry eye after 1 month postoperatively, but by 3 and 6 months, this is no longer the case.
In a prospective study, 241 patients were randomly assigned to bilateral treatment with either wavefront-guided LASIK or PRK using one of two platforms (VISX STAR S4 CustomVue, Advanced Medical Optics [AMO]; LADARVision, Alcon Laboratories). Those who underwent the surface procedure were treated with an epithelial scrubber (Amoils, Innovative Excimer Solutions Inc.) to remove the epithelium and received a bandage contact lens, tetracaine, topical antibiotic, and fluorometholone tapered over 2 months. Patients in the LASIK group were treated with a 15-kHz femtosecond laser (IntraLase, AMO) used to create a superior-hinged flap measuring 100 μm. They received topical antibiotic and a steroid for 1 week postoperatively.
Patients were asked to complete a questionnaire about their dry eye symptoms before and after surgery to determine the severity of the dry eye, the frequency of artificial tear use, and the effect of dry eye symptoms on daily living activities. The results were quite enlightening, said Dr. Schallhorn, director, refractive surgery, U.S. Navy, Naval Medical Center San Diego.
"LASIK [patients] had more symptoms than PRK [patients], but at 3 and 6 months postoperatively, there were no differences in symptoms" between the two groups, Dr. Schallhorn said. "In fact, PRK [patients] had more symptoms (4%) than LASIK [patients] (3%) at 6 months, although the difference was not significant."
The use of artificial tears also increased significantly following refractive surgery regardless of the procedure undertaken. At 1 month postop, the mean tear drop use had risen above two drops daily, but by 3 months it had fallen to about 1 drop daily.
"The use of artificial tears decreased at 6 months postoperatively yet was still above the baseline figure (of less than 0.5 drop daily)," Dr. Schallhorn noted.
More females than males experienced dry eye symptoms before refractive surgery, and this trend continued after surgery, he continued. In addition, patients who wore glasses before surgery were more likely to have dry eye complaints than those individuals who wore contact lenses, Dr. Schallhorn reported. At 6 months postoperatively, the mean frequency of symptoms in the cohort wearing glasses was 1.74, whereas those wearing contact lenses had a score of only 0.34.
Dry eye complaints were higher with increasing age of the patient population, although the average age was just above 30 years.
"Patients with dry eye symptoms also noted that they had more problems with their daily activities" at 1 month postop, Dr. Schallhorn said. "When we examine these patients postop, another reason to treat their dry eye symptoms is [that] it is related to problems with their daily activities."
When the researchers examined the relationship between the amount of myopia or cylinder treated compared with dry eye symptoms, they found no correlation. This differs from previous reports that suggest that dry eye symptoms are related to the amount of tissue removed by the excimer laser, Dr. Schallhorn said.
"We found more dry eye symptoms in the LASIK group at 1 month postoperatively than the PRK group, but surprisingly not at 3 and 6 months postop," Dr. Schallhorn said. "We expected LASIK to have more symptoms than PRK at every postoperative period. PRK may have more symptoms at 6 months postop if we did a larger study. There are, however, other more important factors related to dry eye, such as gender, age, and wearing glasses before surgery."
It is important to note that dry eye symptoms are related to problems with daily activities, and to treat it appropriately, he said.