Excimer laser-assisted corneal epithelial pattern ablation for corneal cross-linking

J. Brekelmans*, M.M. Dickman, S. Verma, S. Arba-Mosquera, R. Goldschmidt, A. Goz, A. Brandis, T.T.J.M. Berendschot, I.E.Y. Saelens, A.L. Marcovich, A. Scherz, R.M.M.A. Nuijts

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Purpose To determine corneal cross-linking (CXL) efficacy and chromophore penetration after excimer laser-assisted patterned de-epithelialization. Methods Two-hundred-twenty porcine eyes were de-epithelialized ex vivo, either fully (mechanical; n = 88) or patterned (excimer laser; n = 132). Consecutively, corneas were impregnated with hypo- or hyperosmolar riboflavin (RF; n = 20, RF-D; n = 40, respectively) or water-soluble taurine (WST11; n = 40, and WST-D; n = 40, respectively), or kept unimpregnated (n = 80). Sixty corneas were subsequently irradiated, inducing CXL, with paired contralateral eyes serving as controls. Outcome measurements included strip extensiometry to assess CXL efficacy, and spectrophotometry and fluorescence microscopy to determine stromal chromophore penetration. Results All tested chromophores induced significant CXL (p < 0.001), ranging from 7.6% to 14.6%, with similar stiffening for all formulations (p = 0.60) and both de-epithelialization methods (p = 0.56). Light transmittance was significantly lower (p < 0.001) after full compared with patterned de-epithelialization. Stromal chromophore penetration was comparable between fully and patterned de-epithelialized samples, with full penetration in RD and RF-D samples and penetration depths measuring 591.7 +/- 42.8 mu m and 592.9 +/- 63.5 mu m for WST11 (p = 0.963) and 504.2 +/- 43.2 mu m and 488.8 +/- 93.1 mu m for WST-D (p = 0.669), respectively. Conclusions Excimer laser-assisted patterned de-epithelialization allows for effective CXL. Stromal chromophore concentration is, however, reduced, which may have safety implications given the need for sufficient UVA attenuation in RF/UVA CXL. The different safety profile of near-infrared (NIR) may allow safe WST11/NIR CXL even with reduced stromal chromophore concentration values. In vivo studies are needed to evaluate the benefits and further assess safety of excimer laser-assisted patterned de-epithelialization for corneal CXL.
Original languageEnglish
Pages (from-to)422-430
Number of pages9
JournalActa Ophthalmologica
Issue number4
Early online date17 Sept 2021
Publication statusPublished - Jun 2022


  • corneal cross-linking
  • WST11
  • riboflavin
  • excimer laser


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