Eyeworld

EW RESIDENTS 47 study design arises from the manner in which the study protocol ad- dressed contact lens wear and cessa- tion. Patients were instructed to remove their contact lenses at the same time each day since most were unable to stop wearing their lenses for a full 2 weeks. There is no data provided on the percentage of pa- tients who completed the full course without contact lens wear or the av- erage time without lenses before ker- atometry measurements were performed—both prior to and after CXL. The authors rightly speculate that the limited period of contact lens cessation could have led to an overestimation of the failure rate of CXL by underestimating keratomet- ric progression at enrollment. After 1 year of follow-up, less than half of the eyes (n=64) re- mained in the study, which repre- sents a potential source of effect bias. The authors hypothesize that the high loss in follow-up may have resulted from improvement in the patients' symptoms, resulting in a reduced perceived need for care. Conversely, no improvement or worsening symptoms post-CXL may have led these lost patients to seek alternate care elsewhere. One out- come measure of the study was to report the effect of corneal collagen crosslinking on endothelial cell count and corneal biomechanics as measured by the ORA. However, these parameters were measured in only a small minority of patients leaving potentially important ques- tions unanswered. Finally, we feel that the assessment of outcomes in this study could have been strength- ened by performing subgroup analy- sis based on the severity of keratoconus in enrolled eyes as this may help us better understand which patients will derive the most benefit from crosslinking. In summary, this large retro- spective study confirms and sup- ports existing data regarding the efficacy of CXL in progressive kera- toconus while providing intriguing new insights into potential failure indicators and a previously unre- ported complication. This article outlines the need for a large prospec- tive, well-controlled study of CXL for progressive keratoconus, such as the U.S. FDA phase III trial currently underway. In addition, the few limi- tations of this paper, such as inade- quate standardization of contact lens wear, lack of fellow eye con- trols, and lack of subgroup analysis based on severity, could be instruc- tive to future protocols to help bet- ter define the clinical role of CXL. EW Contact information Starr: drstarr@gmail.com Save the Date! 2012 ASCRS•ASOA Symposium and Congress Saturday, April 21, 2012 7:00 – 9:30 AM McCormick Place CME credit is not available for Corporate Mornings programs. www.eyeworld.org C in progressive keratoconus: Multicenter results from the French National Reference Center for Keratoconus" December 2011

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