A study conducted in Germany and presented yesterday at the 2019 ARVO meeting suggests that practitioners should examine keratoconus patients at regular intervals, especially five years after performing corneal collagen crosslinking (CXL), to recognize and re-treat progression early. Researchers defined a satisfactory response to CXL as a postoperative stabilization of K­_max of an increase of more than two diopters or any decrease of K_max.

The researchers analyzed 168 eyes of 131 patients who were treated with standard CXL. Retrospective follow-up was one (n=103 eyes) to a maximum of 10 years (n=44 eyes). After CXL, median K₂ increased by 0.1D after one year, but then decreased over the remaining postoperative period by 0.85D after 10 years. Mean apical corneal thickness decreased by 11µm, 9µm and 3µm after three, seven and 10 years, respectively. Median K_max showed high variation with no significant change. After 10 years, the study noted a 0.1D increase. Mean best-corrected visual acuity (logMAR) significantly increased by 0.14 after two years and then by 0.15 after five and 10 years.

One, seven and 10 years post-CXL, 87.8%, 81.1% and 66.7% of eyes met the responder criteria, respectively. The researchers re-treated four eyes, one each that were three and four years after CXL, respectively, and two eyes that were five years post-op. There were no complications in repeating CXL, and keratoconus stabilized afterwards.