Czech and Slovak Ophthalmology 339 10.31348/2024/37 Original article Long-Term Refractive and Topographical Changes in Keratoconic Eyes after Accelerated Corneal Crosslinking Benca Kapitánová Karolína https://orcid.org/0000-0001-9209-0223 Javorka Michal https://orcid.org/0000-0001-7562-5193 Vida Rastislav Ťažandláková Monika Budinská Miroslava Králik Michal https://orcid.org/0000-0001-8566-7637 Žiak Peter https://orcid.org/0000-0002-3910-6174 Halička Juraj https://orcid.org/0000-0003-0234-3616 27 8 2024 1 2

Aim: To evaluate the long-term impact of accelerated corneal cross-linking (A-CXL) on selected refractive and topographical parameters in eyes with progressive keratoconus. Methods: 77 eyes with keratoconus in 54 patients treated with A-CXL (10 min "epi-off" protocol) were included in the analysis. Preoperative and postoperative (1, 3 and 5 years after A-CXL) values of the studied parameters were compared. Results: In the cohort, there was an improvement in best corrected central visual acuity (BCCVA) 1 year (p = 0.004) and 3 years (p < 0.001) after A-CXL. Values of cylindrical component of refraction (Dcyl) (p = 0.043; p = 0.009; p = 0.063), maximum anterior corneal surface curvature (Kmax) (p = 0.003; p < 0.001; p ˂ 0.001), Coma aberration (p = 0.023; p ˂ 0.001; p = 0.005) and minimum corneal thickness (Pachymin) (p ˂ 0.001; p = 0.003; p = 0.034) were reduced at 1 year, 3 years and 5 years after surgery. The value of the steepest meridian of the anterior corneal surface (K1) was reduced only at 3 years and 5 years after surgery (p = 0.007; p = 0.012). In the year-to-year comparison 1 year vs. 3 years after surgery, there was a continued improvement in K1 (p = 0.024), the flattest meridian of the anterior corneal surface (K2) (p = 0.012), Kmax (p = 0.001) and Coma (p ˂ 0.001) values, and this also applied 1 year vs. 5 years after A-CXL in the case of Kmax (p = 0.001) and Coma (p = 0.049). We confirmed that the younger the patient at the time of A-CXL, the more pronounced the decline in Kmax at the 3-year interval after the procedure. Furthermore, we observed a significant correlation between the maximum preoperative anterior corneal surface curvature (Kmax_0) and the change in the DCyl parameter 1 and 3 years after A-CXL, as well as between Kmax_0 and the postoperative decrease in Kmax 5 years after surgery. Conclusion: In the cohort, there was a favorable change in most of the analyzed parameters (BCCVA, Dcyl, K1, K2, Kmax, Coma, and Pachymin) and a trend towards a further decrease in K1, K2, Kmax, and Coma values at 3 years, and subsequently in Kmax and Coma at 5 years after surgery, was confirmed.

 progressive keratoconus accelerated corneal cross-linking refractive and topographical parameters References Vazirani J, Basu S. Keratoconus: current perspectives. Clin ophthalmol. 2013;7:2019-2030. Rabinowitz YS. Keratoconus. Surv Ophthalmol. 1998;42:297-319. Wollensak G, Spoerl E, Seiler T. Riboflavin/ ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003;135:620-627 Caporossi A, Mazzotta C, Baiocchi S, Caporossi T. Long-term results of riboflavin ultraviolet a corneal collagen cross-linking for keratoconus in Italy: the Siena eye cross study. Am J Ophthalmol. 2010;149(4):585-593. Raiskup F, Spoerl E. Corneal crosslinking with riboflavin and ultraviolet A. I. Principles. Ocul Surf. 2013;11(2):65-74. Mazzotta C, Raiskup F, Hafezi F, Torres-Netto EA, Armia Balamoun A, Giannaccare G, Bagaglia SA. Long term results of accelerated 9 mW corneal crosslinking for early progressive keratoconus: the Siena Eye-Cross Study 2. Eye Vis (Lond). 2021 May 1;8(1):16. Salman A, Ali A, Rafea S, et al. Long-term visual, anterior and posterior corneal changes after crosslinking for progressive keratoconus. Eur J Ophthalmol. 2022 Jan;32(1):50-58. Eslami M, Ghaseminejad F, Dubord PJ, Yeung SN, Iovieno A. Delayed topographical and refractive changes following corneal cross-linking for keratoconus. J Clin Med. 2022 Mar 31;11(7):1950. Gomes JAP, Tan D, Rapuan ChJ, et al. Global Consensus on Keratoconus and Ectatic Diseases. Cornea. 2015 Apr;34(4):359-369. Kandel H, Abbondanza M, Gupta A, Mills R, Watson AS, Petsoglou C, Kerdraon Y, Watson SL. Comparison of standard versus accelerated corneal collagen cross-linking for keratoconus: 5-year outcomes from the Save Sight Keratoconus Registry. Eye (Lond). 2024 Jan;38(1):95-102. Deshmukh R, Ong ZZ, Rampat R, et al. Management of keratoconus: an updated review. Front. Med. 2023 Jun;10:1212314. Mohammadpour M, Heidari Z, Hashemi H. Updates on Managements for Keratoconus. J Curr Ophthalmol. 2017 Dec 6;30(2): 110-124. De Bernardo M, Capasso L, Lanza M, et al. Long-term results of corneal collagen crosslinking for progressive keratoconus. J. Optom. 2015;8:180-186. Veselý P, Veselý Ľ, Combová V, Žukovič M. Specific corneal parameters and visual acuity changes after corneal crosslinking treatment for progressive keratoconus. Cesk Slov Oftalmol. 2021;77(4): 184-189. Raiskup F, Theuring A, Pillunat LE, Spoerl E. Corneal collagen crosslinking with riboflavin and ultraviolet-A light in progressive keratoconus: Ten-year results. J Cataract Ref Surg. 2015;41:41-46.