Both conventional corneal collagen crosslinking (CXL) and accelerated CXL (A-CXL) can halt the progression of keratoconus, investigators say, but A-CXL has the added benefit of causing less haze and fewer long-term risks of continuous flattening. Doctors and patients alike have reason to prefer the A-CXL protocol, as it reduces procedure time, as long as outcomes aren't compromised relative to conventional CXL.

The Japanese research team, who presented their findings yesterday at the 2019 Association for Research in Vision and Ophthalmology (ARVO) meeting, looked at 22 eyes of 21 progressing keratoconus patients who underwent epithelium-off CXL treatment. Twelve eyes of 11 patients underwent conventional CXL, which involves a 0.1% riboflavin instillation and 3.0mW/mm² UVA irradiation for 30 minutes. The other 10 underwent the A-CXL, which uses a higher-intensity 18mW/mm² UVA irradiation for only five minutes.

While best-corrected visual acuity, thinnest corneal thickness and corneal endothelial cell densities were similar between the two groups, steepest keratometric values were significantly different, with the conventional CXL patients showing more flattening compared with the A-CXL at one year, and the difference increasing thereafter through the five-year study period. Also at five years, 58.3% of the conventional CXL group had flattening Ks of more than 1D—none in the A-CLX group exhibited the same finding. Finally, corneal densitometry was significantly higher after conventional CXL than A-CXL from one month to one year after the procedure.