Although the Dresden protocol for corneal collagen crosslinking (CXL) remains the conventional choice for treating keratoconus, new data suggests the accelerated protocol is just as effective. Researchers used Scheimpflug tomography to measure corneal parameters before and after 58 eyes with keratoconus progression underwent CXL with either Dresden or accelerated protocols.
Preoperatively, both groups showed similar rates of significant progression, as measured by three different parameters: D value, thinnest pachymetry and Kmax. Specifically, differences in the D value were higher, but not significant, in the Dresden cohort than in the accelerated cohort.
Postoperatively, however, the Dresden protocol showed a larger decrease in the D value compared with the accelerated protocol, effectively equaling a reduction in keratoconus. Despite this difference, the researchers note none of the variables showed a significant progression postoperatively, suggesting both methods effectively halted disease progression.
The value in the results, according to the study authors, is the use of three different measurements of relevant variables for keratoconus progression to establish preoperative corneal stability trends.
“We know that keratoconus progression can slow down by itself in the course of aging, so it remains unclear whether the effect is caused by CXL or just a physiological process,” the author said. “Therefore, the strength of this study is the multiple preoperative measurements, which allow us to make a clear statement about the current progression of keratoconus for each patient before promising a CXL procedure and to exclude the possibility of corneal stabilization even before CXL was performed, for example, by aging.”
|Shajari M, Sowwa G, Steinwender G, et al. Comparison of corneal collagen cross-linking protocols measured with Scheimpflug tomography. Cornea. 2018;37(7):870-4.|