The Changes of Tear Break Up Time after Myopic Excimer Laser Photorefractive Keratectomy

We compared the tear break-up time (BUT) and Schirmer test value after myopic excimer laser photorefractive keratectomy (PRK). Patients with normal preoperative Schirmer test value and BUT were included. Pre- and post-operative tear break-up time and Schirmer test values were measured in 220 eyes who underwent PRK. Minimum follow-up was 6 months. Visx 20/20 B excimer laser was used for myopic PRK. Six months after surgery, no significant changes in Schirmer test value between pre- and post-operation were observed. However, 47.8% of eyes showed a decrease in BUT after surgery, and 72.7% of patients with decreased BUT complained of dry eye symptom. There was no significant relationship between BUT changes and uncorrected visual acuity after PRK. BUT changes did not influence the PRK visual outcome, but excimer laser PRK may change the tear break-up time and cause a dry eye symptom.