Quantitative changes in tear film after refractive surgery: comparative study between PRK and LASIK

PURPOSE: To compare quantitative changes induced in the tear film of patients submited to photorefractive keratectomy and LASIK over a year. METHODS: A prospective, longitudinal, comparative, post-interventional study was designed to distinguish tear film changes before and one year after refractive surgery procedures in 48 patients submited to PRK and 36 patients submited to LASIK, using type 1 Schirmer test in the right eye and red phenol thread test in the left eye. RESULTS: Tear film assessment between the first and third postoperative month demonstrated Schirmer and phenol red measurements below basal values for both procedures. One year after the procedures, measurements returned to presurgical values. CONCLUSION: Besides momentary and within normal limit changes in the measurement of tear film, no complications were found in normal patients.