letters to the editor

Corneal CXL: Epi-Off is More Effective

I read with interest the article by Vishakha Thakrar, OD, FAAO, titled, "New Protocols for Managing Keratoconus and Corneal Ectasia" that published in the April 2013 issue. The article is very well written and appropriately referenced.

However, I need to correct one section in which my chapter from the International Ophthalmology Clinics is referenced and where there was a misunderstanding of what I stated. We did not demonstrate and we do not advocate the transepithelial approach for corneal collagen cross-linking (CXL) in most cases. In fact, we believed then and still believe now that the epithelium-off procedure is the one that is safe and efficacious as stated in our chapter, not the epi-on procedure. Since publication of that chapter, even more peer-reviewed papers have supported that belief.

It would be helpful if one day the epi-on procedure is shown to be as effective as the epi-off procedure, but that day has not yet come. We appreciate Dr. Thakrar's citing our work on CXL, and we look forward to more advances in this exciting field.

Ronald N. Gaster, MD, FACS, Clinical Professor, Ophthalmology Gavin Herbert Eye Institute, UC Irvine and Beverly Hills, Calif.

Dr. Thakrar's Response:

I appreciate Dr. Gaster's comments on my article. Dr. Gaster is correct that the majority of research to date demonstrates that the epi-off technique of CXL is more efficacious. I unfortunately misreferenced Dr. Gaster with respect to the statement I made on the efficacy of the epi-on procedure. I meant to reference a 2012 paper by Stojanovic et al titled "Safety and Efficacy of Epithelium-On Corneal Collagen Cross-Linking Using a Multifactorial Approach to Achieve Proper Stromal Riboflavin Saturation." This paper, along with research by Fillipello et al (2012) and Magli et al (2013), demonstrates that the transepithelial cross-linking procedure potentially may be a safe and efficacious procedure for patients who have keratoconus. I apologize to the researchers involved for making this referencing error.

For references, please visit www.clspectrum.com/references.asp and click on document #217.