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

PURPOSE To compare the clinical outcomes between pulsed and continuous accelerated crosslinking for keratoconus. SETTING Hospital. DESIGN Retrospective comparison study. METHODS Korean patients who were treated for keratoconus between September 2015 and January 2018 at Seoul St. Mary's Hospital were included. Eyes were subjected to pulsed accelerated crosslinking (30 mW/cm for 8 min, 1 second on/1 second off) or continuous accelerated crosslinking (30 mW/cm for 4 min; delivering 7.2 J/cm). Outcomes were evaluated after 1 year. RESULTS At 1 year, the two groups did not exhibit changes in their corrected and uncorrected distance visual acuity values. The pulsed group (25 eyes) exhibited significantly improved values for sphere (p=0.009) and spherical equivalent (p=0.033), although no significant difference was observed in the continuous group (20 eyes). All keratometry values (SimKf, SimKs, SimKmean, and Kmax) were improved in both groups (all p<0.05), although the pulsed group had significantly greater changes in the SimKmean value (p=0.036) and the Kmax value (p=0.03). Both groups had significantly decreased central and thinnest corneal thicknesses (all p<0.001), although the pulsed group had a substantially lower thinnest corneal thickness (p=0.017). Corneal densitometry measured using the Pentacam® device (Oculus Inc., Wetzlar, Germany) was increased in both groups (all p<0.001), with a higher densitometry value in the pulsed group (p=0.013). Furthermore, the depth of the demarcation line was deeper in the pulsed group (p=0.015). CONCLUSIONS Pulsed accelerated crosslinking may provide better post-crosslinking effects than continuous accelerated crosslinking.