Penetration of riboflavin and postoperative pain in corneal collagen crosslinking: excimer laser superficial versus mechanical full-thickness epithelial removal.

PURPOSE: To compare the severity of postoperative pain and the rate of penetration of riboflavin between eyes treated by corneal crosslinking (CXL) using excimer laser superficial epithelial removal and mechanical full-thickness epithelial removal.
SETTING: Departments of Ophthalmology, Ullevål University Hospital, Oslo, and University Hospital of Northern Norway, Tromsø, Norway.
METHODS: Patients with corneal ectasia were treated with superficial corneal epithelial removal using the excimer laser programmed to 35 mum of phototherapeutic keratectomy (Group 1) or mechanical full-thickness epithelial removal with a brush (Group 2). Pain was evaluated postoperatively by the patients' subjective evaluation and need for analgesia. The duration of topical application of riboflavin to achieve stromal saturation was measured.
RESULTS: Thirty eyes of 30 patients, 15 in each group, were treated. Postoperative pain was severe in 40.0% of patients in Group 1 and in no patient in Group 2 (P = .009) and moderate in 53.3% and 33.3%, respectively (no significant difference). The mean time to riboflavin saturation was 43.7 minutes +/- 10.8 (SD) in Group 1 and 31.3 +/- 3.0 minutes in Group 2 (P = .001).
CONCLUSION: Superficial epithelial removal using the excimer laser resulted in more postoperative pain and the need for prolonged application of riboflavin to achieve corneal saturation.