Comparison of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in keratoconus treatment

PURPOSE: To compare the severity and duration of ocular discomfort after three different epithelial debridement techniques for corneal collagen cross-linking in the treatment of keratoconus. METHODS: Fifty-five patients (65 eyes) known to have keratoconus were enrolled in this retrospective study. The eyes were divided into three groups based on the technique used for epithelial debridement for corneal collagen cross-linking procedure; excimer laser transepithelial phototherapeutic keratectomy was used in group 1 (18 eyes), alcohol-assisted epithelial removal was used in group 2 (27 eyes), and mechanical epithelial debridement was used in group 3 (20 eyes). Preoperative and postoperative (third month) best-corrected visual acuity (BCVA) using Snellen chart, objective refraction, and keratometry results were recorded. The results of the questionnaire obtained from the patient’s medical records were reviewed regarding their subjective evaluation of postoperative symptoms including foreign body sensation, tearing, photophobia, and burning at the end of the first postoperative week. Paired-samples t test was used to compare preoperative and postoperative clinical findings. One-way analysis of variance (ANOVA) was used to analyze the differences between three independent groups. RESULTS: BCVA improved from 0.51 ± 0.27 to 0.58 ± 0.21 (p = 0.05). Objective mean spherical and cylindrical refraction decreased from −5.08 ± 2.78D to −4.46 ± 2.91D (p = 0.22) and from −3.45 ± 2.73D to −3.03 ± 1.97D (p = 0.25). Mean maximum keratometry reading (K(max)) decreased from 57.63 ± 4.73D to 56.13 ± 4.47D (p = 0.001). The mean score for foreign body sensation was the highest in group 3 (4.50 ± 0.53) and the lowest in group 1 (2.10 ± 1.85) (p = 0.01). The mean scores for tearing, photophobia, and burning sensation were comparable in three groups (p = 0.84, p = 0.13, and p = 0.61, respectively). The duration of photophobia was the shortest in group 1 (1.50 ± 2.37 days), followed by group 3 (2.00 ± 1.31 days) and group 2 (4.00 ± 1.83 days) (p = 0.04). CONCLUSIONS: The severity and duration of adverse subjective symptoms during the first postoperative week after corneal collagen cross-linking appear to be milder with epithelial debridement using excimer laser transepithelial technique compared with -assisted debridement and mechanical debridement.