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, Ulleval University Hospital, Oslo, and University Hospital of Northern Norway, Tromso, Norway. Methods Patients with corneal ectasia were treated with superficial corneal epithelial removal using the excimer laser programmed to 35 μm 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.