Corneal collagen crosslinking (CXL) is an established technique that is now used fairly extensively, and excellent scientific work has been conducted to rationalize its use in patients with inadequate corneal tensile strength and thus an unstable cornea. Translation to clinical application has occurred; however, is it effective? This month’s cover focus will explore several facets of CXL for keratoconus, including treatment protocols and short- and long-term data.
As the goal of the procedure is to stabilize the condition of the cornea—in other words, to ensure there is no change for the worse— measures of efficacy are proving to be difficult to establish. Coupled with the fact that each keratoconic cornea is unique in its dimensions, we must remember that the devices we use to measure abnormal corneas have a level of instrument error. This further contributes to the difficulty of establishing the certainty of the effect of CXL.
Jerome C. Vryghem, MD, PhD, of Belgium, Brussels, recently organized a private meeting of keratoconus experts at the latest European Society of Cataract and Refractive Surgeons (ESCRS) meeting in Paris. The topics related to surgical visual rehabilitation of keratoconus, including CXL, intrastromal corneal ring segments, phakic implants, transplantation, and surgical combinations of the above treatments. The fundamental sources of frustration were defining the magnitude of keratoconus using more advanced topographic methods and defining progression. There are some accepted general criteria, like use of the KMax feature on the Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany); however, to date there is no consensus on use of other parameters.
The number of variables associated with keratoconus makes analysis difficult. The answer lies in the development of an expert system for analyzing and interpreting these variables and comparing sequential topographic maps. Those of us ophthalmologists across the globe with an interest in or who are involved with keratoconus research will hopefully play a significant role in this area, working with the providers of our tools to achieve such a goal.
Despite the issues that we must still overcome with regard to defining the magnitude and progression of keratoconus, at least we now have a wonderful addition to our armementarium—CXL—which holds the promise of benefitting a large group of patients. Further developments continue to surface, including variations in how to perform the procedure as well as the use of higher energy in an approach some refer to as rapid crosslinking.
This cover focus contains a roundtable discussion on CXL that reviews approaches to visual rehabilitation of eyes with ectasia. Chaired by William B. Trattler, MD, of Miami, this lively discussion illustrates differing viewpoints among CXL experts; it certainly makes for entertaining reading. I participated in the live roundtable, and I enjoyed hearing— and contributing to—the differing opinions. Events such as this are how boundaries are broken. In time, and of course built on the basis of scientific evidence, there will inevitably be a convergence in approach. Until then, we remain in relatively uncharted territory.
2010 has gone by rapidly, and despite severe recessionary influences, this year has been fairly vibrant in terms of cataract, corneal, and refractive surgery. Again I would like to take the opportunity to thank the wonderful publishing and editorial team at CRST Europe, along with my Co-Chief Medical Editors and friends Khiun F. Tjia, MD, and Erik L. Mertens, MD, FEBO. We have had some wonderful and landmark publications this year, which I know many have you have not thrown away. Thank you, too, for your unyielding support.
I wish you all a very happy and prosperous 2011.