We would like to respond to the comments by Zhang and associate regarding our article entitled “Corneal collagen cross-linking with riboflavin and ultraviolet-A irradiation in patients with thin corneas,” published in the Journal .

The authors provide general comments regarding the eminent subject of minimum corneal thickness after epithelial removal when performing corneal collagen cross-linking (CXL) treatment in keratoconic and post–laser in situ keratomileusis (LASIK) ectasia patients. It is known that the standard protocol proposes a minimum corneal thickness of 400 μm after epithelial removal, which is necessary for an effective and safe CXL treatment.

In our study we investigated the effect of CXL in thinner corneas, with central pachymetry less than 400 μm. The main conclusions of our study were that in those patients a significant endothelial cell count loss was evident postoperatively, not related with clinically significant corneal edema, and that at the last follow-up examination, a topographic stabilization of the ectasia was apparent in our patient series.

In our article we did not suggest an extension of the protocol in thinner corneas; we merely commented on the fact that a large percentage of keratoconic and post-LASIK ectasia patients has thin corneas that apparently do not fulfill the criteria for the standard CXL procedure.

Zhang and associate’s comments on the standard corneal collagen cross-linking procedure for the patient with a thin cornea are not specifically addressed as a response to our article and can be considered general comments on the subject of the enhancement of safety when performing the standard CXL procedure.