Standard corneal crosslinking (epi-off CXL) was safer and more effective than accelerated transepithelial (A-epi-on) CXL in halting the progression of pediatric progressive keratoconus (KC), according to a study published in Cornea.

In this prospective cohort study, researchers evaluated and compared the 5-year efficacy and safety of the epi-off and the A-epi-on CXL procedures performed between September 2008 and September 2014 in consecutive pediatric patients with KC. Boys (n=36; 55.38%) and girls (n=29; 44.62%) were included for a total of 78 eyes. Epi-off CXL was performed in 46 eyes and A-epi-on CXL was performed in 32 eyes. Postoperative results were analyzed according to the standard follow-up protocol: at 1, 7, and 30 days after surgery, every 3 months during the first year, every 6 months during the second year, and once a year thereafter. At each follow-up examination, researchers obtained data for manifest refraction, uncorrected visual acuity, best corrected visual acuity (BCVA), slit-lamp examination, and Scheimpflug imaging analysis.

Progression of KC was halted by both the epi-off and A-epi-on CXL procedures, with no statistically significant differences between groups in uncorrected visual acuity, BCVA, sphere, cylinder, steep keratometry (K), and pachymetry. Only 3 patients experienced progression, all of whom were in the A-epi-on CXL group. There was no loss of BCVA lines in the epi-off group, but there was a loss of BCVA lines in all 3 eyes that progressed in the A-epi-on group. Flat, steep, and maximum K did not have significant changes at 12 or 60 months postoperatively in the A-epi-on group, but there was significant flattening of all 3 variables at 60 months with epi-off (0.77±1.41 D, P <.001; 1.02±1.85 D, P =.023; and 1.67±2.22 D, P <.001, respectively). There was also a significant decrease in pachymetry in only the epi-off group (24.40±28.87 µm and 16.67±26.20 µm at 12 and 60 months postoperatively; both P =.001). A significant decrease in anterior elevation values was found in the epi-off group at 60 months follow-up (4.42±5.42 µm, P <.001) but no significant changes in anterior elevation values were found at either 12 or 60 months of follow-up in the A-epi-on group.

“Although epi-off procedure seems to be more effective than A-epi-on procedure, it is important to remember that KC progression in children occurs approximately in 80% of the cases, and in both procedures, the progression was halted in more than 90% of the cases,” the authors said. “It seems that epi-off CXL is more aggressive in flattening K readings when compared with A-epi on procedure, and maybe, this fact should be taken into account when thinking on the desirable effect on the cornea and the risk of progression in each patient.”


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Reference

Henriquez MA, Hernandez-Sahagun G, Camargo J, Izquierdo L. Accelerated epi-on versus standard epi-off corneal collagen cross-linking for progressive keratoconus in pediatric patients: Five years of follow-upCornea. [published online August 11, 2020]. doi: 10.1097/ICO.0000000000002463