NEWS & OPINION 60 EWAP SEPTEMBER 2022 CXL, TECXL, and CACXL simultaneously in one clinic setting. The results of this study suggest that both TECXL and CACXL are comparable to standard epi-off CXL in regard to structural outcomes, as demonstrated by halting progression of ectasia and reduction in Kmax, as well as functional outcomes, as evidenced by improvement in CDVA. Although the exact cut-off for a “thin” cornea remains a topic of debate, TECXL and CACXL performed on corneas as thin as 357 microns in this study showed effective results and no evidence of endothelial toxicity. While the reduction in Kmax was significant among all groups, the greatest reduction was seen in the CACXL group, which was possibly related to the relatively higher baseline Kmax in this group, or the thinner baseline pachymetry—two factors that have both been associated with greater corneal yattening after CXL in previous publications.13,14 Detailed evaluation of depth of treatment demarcation lines as well as endothelial cell structure and function would have been useful to have but were unfortunately not performed in this retrospective study. Complications were minimal and interestingly, only occurred in the TECXL group that did not undergo true epithelial debridement; however, exposure of the corneas to significant amounts of benzalkonium chloride in the riboyavin solution may have rendered the epithelium more irregular and susceptible to keratitis in these patients. The retrospective nature, limited sample size particularly in the TECXL and CACXL groups, and lack of randomization or systematic selection of 8L techniµues are notable limitations that may have prevented some observed trends from reaching statistical significance. Conclusions The results of this study suggest that both TECXL and CACXL are comparable to standard epi-off CXL in regressing and/ or stabilizing progressive keratoconus over a 2-year follow-up period. Each of these three techniµues must be chosen judiciously and can play a useful role in the treatment of patients with progressive keratoconus, with TECXL and CACXL being particularly useful in patients with the thinnest pachymetric readings below 400 microns. More research with larger sample sizes and standardized treatment protocols are needed to investigate these techniµues further and help clinicians determine when and in which patients each of these techniµues should be implemented to treat corneal ectasias. EWAP References 1. Subasinghe SK, et al. Current perspectives on corneal collagen crosslinking (CXL). Graefes Arch Clin Exp Ophthalmol. 2018;256:1363–1384. Ó. Wollensak G, et al. RiboyavinÉ ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003;135:620–627. 3. Podskochy A. Protective role of corneal epithelium against ultraviolet radiation damage. Acta Ophthalmol Scand. 2004;82:714–717. 4. Malhotra C, et al. In vivo imaging of riboyavin penetration during collagen cross-linking with hand-held spectral domain optical coherence tomography. J Refract Surg. 2012;28:776–780. 5. Wollensak G, Iomdina E. Biomechanical and histological changes after corneal crosslinking with and without epithelial debridement. J Cataract Refract Surg. 2009;35:540–546. 6. Spoerl E, et al. Safety of UVA- riboyavin cross-linking of the cornea. Cornea. 2007;26:385–389. 7. Dhawan S, et al. Complications of corneal collagen cross-linking. J Ophthalmol. 2011;2011:869015. 8. Leccisotti A, Islam T. Transepithelial corneal collagen cross-linking in keratoconus. J Refract Surg. 2010;26:942–948. 9. Cifariello F, et al. Epi-off versus epi-on corneal collagen cross-linking in keratoconus patients: A comparative study through 2-year follow-up. J Ophthalmol. 2018;2018:4947983. 10. Magli A, et al. Epithelium-off corneal collagen cross-linking versus transepithelial cross-linking for pediatric keratoconus. Cornea. 2013;32:597–601. 11. Soeters N, et al. Transepithelial versus epithelium-off corneal cross-linking for the treatment of progressive keratoconus: a randomized controlled trial. Am J Ophthalmol. 2015;159:821–828.e3 12. Jacob S, et al. Contact lens-assisted collagen cross-linking (CACXL): A new techniµue for cross-linking thin corneas. J Refract Surg. 2014;30:366–372. 13. Greenstein SA, Hersh PS. haracteristics inyuencing outcomes of corneal collagen crosslinking for keratoconus and ectasia: implications for patient selection. J Cataract Refract Surg. 2013;39:1133–1140. 14. Spadea L, Mencucci R. Transepithelial corneal collagen cross-linking in ultrathin keratoconic corneas. Clin Ophthalmol. 2012;6:1785–1792.
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