Long-Term Results of Phototherapeutic Keratectomy Versus Mechanical Epithelial Removal Followed by Corneal Collagen Cross-Linking for Keratoconus

PURPOSE: To compare the long-term visual outcomes of patients with keratoconus treated with either phototherapeutic keratectomy (PTK) or mechanical epithelial removal before corneal collagen cross-linking (CXL) at 1, 3, 6, and 12 months postoperatively. METHODS: CXL was performed by 1 of 3 surgeons (K.B., W.B.J., or G.M.). Seventeen eyes underwent mechanical epithelial removal before CXL and were consecutively selected after being matched with the 17 eyes in the PTK group for the variables of procedure date, average keratometry, and pachymetry. All cones were central. Manifest refraction spherical equivalent, sphere, cylinder, corrected distance visual acuity (CDVA), and pachymetry were measured and compared preoperatively and in follow-up. RESULTS: The mean CDVA change in the PTK group at 12 months postoperatively was statistically different from the mean CDVA change in the mechanical group at 12 months postoperatively (P = 0.031). The PTK group had significantly better outcomes in visual acuity 12 months postoperatively than did the mechanical group (P > 0.05). The mean number of lines of improvement in the PTK and mechanical groups were 2.30 ± 0.96 and 0.00 ± 0.33 lines, respectively (P = 0.0036). The mean change between the preoperative and 12 months postoperative manifest refraction spherical equivalent for the PTK and mechanical groups were 0.78 ± 0.65 and 0.17 ± 0.65, respectively (P > 0.05). CONCLUSIONS: PTK CXL resulted in better visual outcomes in comparison with mechanical epithelial removal CXL 1 year after treatment.