One-Year Follow-Up of Changes in Corneal Densitometry After Accelerated (45 mW/cm2) Transepithelial Corneal Collagen Cross-Linking for Keratoconus: A Retrospective Study

Purpose:The objective of this study is to investigate changes in corneal densitometry after accelerated transepithelial corneal collagen cross-linking (ATE-CXL) for patients with progressive keratoconus (KC).Methods:Seventeen progressive KC patients who underwent ATE-CXL (KC group) were examined and compared against 17 non-KC myopes (control group). For the KC group, corneal topography and densitometry were evaluated preoperatively and at 1, 6, and 12 months postoperatively. Manifest refraction spherical equivalent and best spectacle-corrected distant visual acuity were assessed preoperatively and at 12 months postoperatively. These parameters were also evaluated in the control group.Results:Preoperatively, in the KC group, the densitometry values of the total layer over the annular diameters () 0 to 2 and phi 2 to 6 mm were 18.47 +/- 1.81 and 16.62 +/- 1.60, respectively. In the control group, the values were 14.98 +/- 1.18 and 13.39 +/- 1.33, respectively, significantly lower than those of the KC group (both post hoc P values < 0.001). At postoperative month 12, the densitometry values of phi 0 to 2 and phi 2 to 6 mm of the total layer in the KC group were 16.88 +/- 1.57 and 15.28 +/- 1.40, which were significantly lower than the preoperative values (post hoc P = 0.012 and 0.030, respectively). However, they were still higher than those of the myopes (post hoc P = 0.002 and 0.001, respectively).Conclusions:KC patients have much higher corneal densitometry values than myopes without KC. The KC patients' corneal densitometry values decreased significantly when measured at 12 months after ATE-CXL. However, they remain higher than those of the myopes.