Corneal Collagen Cross‑Linking Using Epithelium Disruptor Instrument in Progressive Keratoconus

To compare the effects of accelerated corneal collagen cross-linking (CXL) in progressive keratoconus (KCN) patients via epitheliumremoval and transepithelial techniques, using Daya Disruptor (Duckworth and Kent, Hertfordshire, UK).

This study is a double-blinded, randomized clinical trial. Patients with documented bilateral progressive KCN were randomized into two groups: one eye underwent epithelium removal (Group 1), and the fellow eye underwent epithelium disruption (Group 2). The primary outcomeswere best corrected visual acuity (BCVA) and uncorrected visual acuity (UCVA), Scheimpflug-extracted keratometric indices, and anteriorsegment-optical coherence tomography-derived epithelial thickness profiles. These parameters were evaluated before and 12 months after CXL.

Sixty-four eyes from 34 patients with progressive KCN (34 eyes in the epithelium-removal group and 30 eyes in the epithelium-disruptiongroup) were included. The mean ± standard deviation (SD) of age was 23.4 ± 3.8 years in the epithelium-removal group and 23.2 ± 3.5 yearsin the epithelium-disruption group. The mean ± SD of the preoperative spherical equivalent (SE), front maximum keratometry (K-max), back K-max, thickness of thinnest point, and corneal apex thickness were − 2.9 ± 3.0 diopter (D) and − 3.7 ± 3.1 D (P = 0.183), 53.8 ± 5.15 D and 54.4 ± 5.53 D (P = 0.653), −6.63 ± 2.40 D and − 6.68 ± 2.48 D (P = 0.131), 459.2 ± 37.4 μm and 460.8 ± 32.7 μm (P = 0.708), 470.5 ± 37.7 μm and 469.7 ± 33.1 μm (P = 0.679), and 55.4 ± 4.97 μm and 54.6 ± 7.16 μm (P = 0.767) in the epithelium-removal and epithelium-disruption groups,respectively. The mean ± SD changes of the UCVA and BCVA 12 months after CXL were − 0.1 ± 0.11 and − 0.02 ± 0.18 and − 0.04 ± 0.12and − 0.02 ± 0.14 in the epithelium-removal and epithelium-disruption groups, respectively. No statistically significant improvement was observedin the UCVA and BCVA between the two groups (P = 0.868 and P = 0.937, respectively). The mean ± SD changes of the SE, superior epithelialthickness, corneal apex thickness, and thickness of thinnest point 12 months after CXL were − 0.21 ± 1.1 D and + 0.32 ± 1.6 D (P = 0.0001),−0.08 ± 0.26 μm and + 0.03 ± 0.33 μm (P = 0.028), −23 ± 11 μm and − 2 ± 6 μm (P = 0.0001), and − 25 ± 8 μm and − 3 ± 7 μm (P = 0.0001) in the epithelium-removal and epithelium-disruption groups, respectively.

This study showed that the epithelium-disruption CXL using Daya has a similar potential for halting KCN progression as the epithelium-removal CXL. However, regarding the 12-month changes, the epithelium-disruption CXL is superior to the epithelium-removal CXL in the SE and corneal pachymetry