FEB 2014

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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Page 91 of 114

the maximum area under the ROC curve of 0.956. Anterior data with significant differences were total higher order aberrations (HOA), residual HOA, 1st, 3rd, and 5th order RMS, C(1,1), C(2,2), C(3,–1) and C(4,–2). Posterior data with significant differences included 6th and 7th order RMS and C(3,–1). Of pachymetry data, only relative data and profile slope values from the pe- ripheral cornea attained significance (P<.05). All output values of previ- ously published and newly calcu- lated discriminant functions showed highly significant intergroup differ- ence (P<0.001). The authors con- cluded that these findings validated the previously studied metric in an expanded population. Comments The study group of "normal" fellow eyes with early keratoconus serves as a valid marker for subclinical kerato- conus given the significant risk of fellow eye progression in cases of seemingly unilateral keratoconus. Additionally, a Bonferroni correction was appropriately used in comparing the multiple parameters to avoid inflating Type 1 error rates. The corneal wavefront and pachymetry- based metrics proved useful for dis- criminating between normal eyes and those with subclinical kerato- conus at a statistically significant level. It was mainly coefficients that represent vertical asymmetry [C(1,– 1), C(3,–1)] and their corresponding RMS values (1st order, 3rd order, and 5th order RMA) that showed marked differences between the normal and subclinical keratoconus populations. The determination that members of the control group did not progress to keratectasia was made by an ex- pert, but single, examiner who was masked to the preoperative topogra- phies to minimize bias. Given the inherent subjectivity of this process, it may have been more appropriate to include multiple examiners and assess inter-observer agreement. Despite the numerous positives associated with this article, there were some weaknesses. The study group was small, consisting of only 32 subjects from a single center. This compromises the generalizability of the article outside this study group due to low power. One way to over- come this would be to include cases Become an ESCRS Member Integral to your continuing education FREE TO MEMBERS: ESCRS On Demand iLearn – online CME accredited learning platform In addition to: Subscription to the Journal of Cataract and Refractive Surgery Reduced ESCRS Congress Fees ESCRS FREE 3 YEAR MEMBERSHIP FOR TR AINEES visit www.escrs.org today 1 16:59 new patient collective" From left to right: First row: Blake Isernhagen, MD, Evan Allan, MD, Yasser Elshatory, MD, PhD; second row: Jeremy Tan, MD, Tyler Sorensen, MD, Jonathan Walgama, MD, James Hoffmann, MD; third row: Andrew Wilson, MD, Derek Bitner, MD, Jared Jackson, MD, Evan Sussenbach, MD; not pictured: Jonathan Perkins, MD Source: John Jernigan continued on page 90 February 2014 84-90 Residents_EW February 2014-DL2_Layout 1 1/30/14 11:13 AM Page 89

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