Study of Demarcation Line Depth in Transepithelial versus Epithelium-Off Accelerated Cross-Linking (AXL) in Keratoconus

Yehia Salah, Kholoud Omar, Ahmed Sherif, Sarah Azzam, Yehia Salah, Kholoud Omar, Ahmed Sherif, Sarah Azzam

Abstract

Aim: This is a prospective interventional clinical trial to assess the depth of the demarcation line in transepithelial versus epithelium-off accelerated corneal cross-linking (AXL) in keratoconus patients.

Methods: This prospective clinical trial was conducted on 40 eyes of 20 patients. Each patient had transepithelial AXL in one eye and epithelium-off AXL in the contralateral eye applying UVA light with an irradiance of 45 mW/cm2 for 2.4 minutes and 30 mW/cm2 for 4 minutes. The depth of the demarcation line was measured using anterior segment OCT (Topcon 3D OCT-2000) one month postoperative for both eyes.

Results: The demarcation line was patchy in 50% of the transepithelial AXL eyes, the other half showing a demarcation line at a mean depth of 183 ± 41.6 μm. In the epithelium-off AXL technique, the demarcation line was well defined in all cases with a mean depth of 219 ± 27.3 μm. There was a statistically significant difference in corneal demarcation line depth between transepithelial and epithelium-off techniques (P = 0.008 and P < 0.05). The shallower demarcation line in the transepithelial group suggests that it is less effective.

Conclusion: Based on the depth of the demarcation line, the cross-linking effect of epi-off AXL seems more efficacious than after transepithelial AXL. The future will show if the biomechanical effect will be sufficient to stop progression of keratoconus similarly after standard CXL. This trial is registered with NCT04045626.

Conflict of interest statement

The authors declare that they have no conflicts of interest.

Copyright © 2019 Yehia Salah et al.

Figures

Figure 1
Figure 1
A patchy corneal demarcation line (white arrow) after transepithelial cross-linking.
Figure 2
Figure 2
A barely visible corneal demarcation line at a central depth of 185 μm after transepithelial cross-linking.
Figure 3
Figure 3
A corneal demarcation line at a central depth of 227 μm after epithelium-off cross-linking.

References

    1. Rabinowitz Y. S. Keratoconus. Survey of Ophthalmology. 1998;42(4):297–319. doi: 10.1016/s0039-6257(97)00119-7.
    1. Wollensak G. Crosslinking treatment of progressive keratoconus: new hope. Current Opinion in Ophthalmology. 2006;17(4):356–360. doi: 10.1097/01.icu.0000233954.86723.25.
    1. Ozgurhan E. B., Sezgin Akcay B. I., Yildirim Y., Karatas G., Kurt T., Demirok A. Evaluation of corneal stromal demarcation line after two different protocols of accelerated corneal collagen cross-linking procedures using anterior segment optical coherence tomography and confocal microscopy. Journal of Ophthalmology. 2014;2014:5. doi: 10.1155/2014/981893.981893
    1. Wollensak G., Spoerl E., Seiler T. Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. American Journal of Ophthalmology. 2003;135(5):620–627. doi: 10.1016/s0002-9394(02)02220-1.
    1. Mazzotta C., Wollensak G., Raiskup F., Pandolfu A. M., Spoerl E. The meaning of the demarcation line after riboflavin-UVA corneal collagen crosslinking. Expert Review of Ophthalmology. 2019;14(2):115–131. doi: 10.1080/17469899.2019.1611425.
    1. Caporossi A., Mazzotta C., Paradiso A. L., Baiocchi S., Marigliani D., Caporossi T. Transepithelial corneal collagen crosslinking for progressive keratoconus: 24-month clinical results. Journal of Cataract & Refractive Surgery. 2013;39:1157–1163. doi: 10.1016/j.jcrs.2013.03.026.
    1. Koppen C., Wouters K., Mathysen D., Rozema J., Tassignon M. J. Refractive and topographic results of benzalkonium chloride-assisted transepithelial cross linking. Journal of Cataract & Refractive Surgery. 2012;38(6):1000–1005. doi: 10.1016/j.jcrs.2012.01.024.
    1. Spoerl E., Huhle M., Seiler T. Induction of cross-links in corneal tissue. Experimental Eye Research. 1998;66(1):97–103. doi: 10.1006/exer.1997.0410.
    1. Spoerl E., Mrochen M., Sliney D., Trokel S., Seiler T. Safety of UVA-riboflavin cross-linking of the cornea. Cornea. 2007;26(4):385–389. doi: 10.1097/ico.0b013e3180334f78.
    1. Moramarco A., Iovieno A., Sartori A., Fontana L. Corneal stromal demarcation line after accelerated crosslinking using continuous and pulsed light. Journal of Cataract & Refractive Surgery. 2015;41(11):2546–2551. doi: 10.1016/j.jcrs.2015.04.033.
    1. Jiang L. Z., Jiang W., Qiu S. Y. Conventional vs. pulsed-light accelerated corneal collagen cross-linking for the treatment of progressive keratoconus: 12-month results from a prospective study. Experimental and Therapeutic Medicine. 2017;14(5):4238–4244. doi: 10.3892/etm.2017.5031.
    1. Bouheraoua N., Jouve L., El Sanharawi M., et al. Optical coherence tomography and confocal microscopy following three different protocols of corneal collagen-crosslinking in keratoconus. Investigative Opthalmology & Visual Science. 2014;55(11):7601–7609. doi: 10.1167/iovs.14-15662.
    1. Kymionis G. D., Tsoulnaras K. I., Grentzelos M. A., et al. Corneal stroma demarcation line after standard and high-intensity collagen crosslinking determined with anterior segment optical coherence tomography. Journal of Cataract & Refractive Surgery. 2014;40(5):736–740. doi: 10.1016/j.jcrs.2013.10.029.
    1. Kymionis G. D., Tsoulnaras K. I., Liakopoulos D. A., Skatharoudi C. A., Grentzelos M. A., Tsakalis N. G. Corneal stromal demarcation line depth following standard and a modified high intensity corneal cross-linking protocol. Journal of Refractive Surgery. 2016;32(4):218–222. doi: 10.3928/1081597x-20160216-01.
    1. Lhuillier L., Ghetemme C., Boiché M., et al. Visibility and depth of the stromal demarcation line after corneal collagen cross-linking using anterior segment optical coherence tomography: comparison between isoosmolar and hypoosmolar riboflavin. Cornea. 2018;37(5):567–573. doi: 10.1097/ico.0000000000001493.
    1. Artola A., Piñero D. P., Ruiz-Fortes P., Soto-Negro R., Pérez-Cambrodí R. J. Clinical outcomes at one year following keratoconus treatment with accelerated transepithelial cross-linking. International Journal of Ophthalmology. 2017;10(4):652–655. doi: 10.18240/ijo.2017.04.24.
    1. Liu Y., Liu Y., Zhang Y. N., et al. Systematic review and meta-analysis comparing modified cross-linking and standard cross-linking for progressive keratoconus. International Journal of Ophthalmology. 2017;10(9):1419–1429. doi: 10.18240/ijo.2017.09.15.
    1. Wollensak G., Iomdina E. Biomechanical and histological changes after corneal crosslinking with and without epithelial debridement. Journal of Cataract & Refractive Surgery. 2009;35(3):540–546. doi: 10.1016/j.jcrs.2008.11.036.

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