• Refractive Mgmt/Intervention

    Review of: Comparison of pulsed and continuous accelerated corneal crosslinking for keratoconus: 1-year results at a single center

    Kang M, Hwang J, Chung S, et al. Journal of Cataract & Refractive Surgery, May 2021

    This single-center, retrospective study compares the outcomes of pulsed and continuous accelerated crosslinking (CXL) for keratoconus.

    Study design

    Twenty-five eyes in the pulsed CXL group received 8 minutes of 1 second on/1 second off CXL at 7.2 J/cm2 while 20 eyes in the continuous CXL group received 4 minutes of continuous CXL at 7.2 J/cm2. Outcome measures included change in UDVA, CDVA, spherical equivalent, keratometry, corneal thinness, corneal densitometry and demarcation line at 1 year.


    Neither group showed a change in UDVA or CDVA. The pulsed group demonstrated significant improvement in spherical equivalent while the continuous group remained unchanged. Both groups had statistically significant improvement in keratometry, but the pulsed group's improvement was significantly greater for some values. Similarly, both groups showed significant decreases in corneal thickness, but pulsed-CXL group had significantly slimmer thinnest corneal thickness. Although data were not available for all subjects, the pulsed group had significantly greater change in densitometry and deeper demarcation line.


    Between the 2 groups, certain parameters showed greater effectiveness in the pulsed accelerated epi-off CXL group than the continuous accelerated epi-off CXL group. The study contains a small number of eyes in each group, and the criteria used for offering continuous versus pulsed treatment are unclear. A high number of eyes were excluded from the analysis and CXL changes may occur even beyond the 1-year time frame of this study.

    Clinical significance

    Although this study has significant limitations, it is valuable as clinicians continue to determine the best method for crosslinking.