This prospective study compared the safety and efficacy of accelerated transepithelial (A-epi-on) corneal collagen crosslinking (CXL) with standard epi-off CXL in children with progressive keratoconus.
The authors enrolled 51 patients (61 eyes) younger than 18 years who had progressive keratoconus.
The first group (36 eyes) underwent accelerated epi-on CXL with 30 minutes of riboflavin application (0.25% riboflavin, 1.0% phosphate hydroxypropyl methylcellulose, 0.007% benzalkonium chloride), followed by 5 minutes of irradiation at 18 mW/cm2.
The second group (25 eyes) underwent standard epi-off CXL with 30 minutes of riboflavin application (riboflavin 0.1% solution, 20% dextran 500), followed by 30 minutes of irradiation at 3 mW/cm2.
Scheimpflug imaging parameters were evaluated preoperatively and at 6 and 12 months postoperatively.
At 12 months postop, BCVA significantly improved by 0.09 logMAR and 0.06 logMAR for the A-epi-on and the epi-off groups, respectively (both P=0.05). The UCVA and mean maximum keratometry, however, did not significantly differ from baseline in either group. Despite these nonsignificant differences, the A-epi-on group had mean increases of +0.23 and +0.1 D for steep and maximum keratometry, respectively; whereas the epi-off group had mean decreases of −0.33 and −0.94 D, respectively.
The groups showed similar changes in pachymetry and posterior elevation values. Keratoconus progression—defined as an increase of 1 D or more in maximum keratometry at 12 months postop—was observed in 5.6% and 12% of eyes in the A-epi-on and epi-off groups, respectively.
This study was not randomized. There were differences between groups in number of eyes (6 in the epi-on and 9 in the epi-off groups) that had maximum keratometry >54 D, which has previously been associated with a higher failure rate. A follow-up period of 12 months may not have been long enough to truly capture progression in this young population.
This study adds to literature comparing epi-on and epi-off protocols for CXL, and finds that both protocols are effective in stopping keratoconus progression in children.