FEB 2014

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

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Boston Fun Fact from multiple centers. There is a possibility that the patients who were selected as the controls may d evelop keratectasia outside the study period (12 months following LASIK). As mentioned by the au- thors, the finding that one patient in the control group developed post- operative keratectasia at a later date adds validity to this concern. Indeed, many cases of post-LASIK ectasia take years to develop. Addi- t ionally, it is unknown whether a control group with significant refrac- tive error undergoing LASIK evalua- tion is representative of the greater normal population. Linear discriminant analysis is based on the Gaussian distribution assumption for each group. While the authors mentioned checking t his assumption in the Patients and Methods section, no testing results were reported. It is thus unclear whether this assumption was met for all the input variables involved in the discriminant functions and checked separately for each group. Non-probability sampling meth- ods were used based on convenience to amass control cases, but this could introduce selection bias. Significant differences in refractive error, sphere, spherical equivalent, and astigmatism existed between the two groups. These large differences are not surprising given the control eyes were preparing to undergo refractive surgery. However, large differences in baseline demographics can hamper the ability to draw appropriate conclusions, as these baseline differences may be poten- tial confounders. Ideally, the authors would have matched for these pa- rameters by having patients with low refractive error in the control group. In summary, this metric holds p romise as a potential method for determining if a patient has subclin- ical keratoconus. While it may serve a purpose in patients with a family history of keratoconus, atopic dis- ease, other risk factors for kerato- conus, or interest in refractive procedures, the ideal of mass public health screenings to identify and t reat at-risk individuals remains elu- sive. The metrics put forth in this study should undergo further valida- tion in a larger, prospective study with a broader distribution of clini- cal characteristics. EW R eferences 1. Buhren J, Kuhne C, Kohnen T. Defining s ubclinical keratoconus using corneal first- surface higher-order aberrations. Am J Ophthalmol 2007; 143:381–389. 2. Li X, Rabinowitz Y, Rasheed K, Yang H. Longitudinal study of the normal eyes in uni- lateral keratoconus patients. Ophthalmology 2004; 111:440–46. 3. Vazirani J, Basu S. Keratoconus: current perspectives. Clin Ophthalmol. 2013;7:2019– 2030. Epub 2013 Oct 14. 4. Smadja D, Touboul D, Cohen A, Doveh E, Santhiago MR, Mello GR, Krueger RR, Colin J. Detection of subclinical keratoconus using an automated decision tree classification. Am J Ophthalmol. 2013 Aug;156(2):237-246.e1. doi: 10.1016/j.ajo.2013.03.034. Epub 2013 Jun 7. 5. Spadea L, Cantera E, Cortes M, Conocchia NE, Stewart CW. Corneal ectasia after myopic laser in situ keratomileusis: a long-term study. Clin Ophthalmol. 2012;6:1801-13. doi: 10.2147/OPTH.S37249. Epub 2012 Nov 2. Contact information Siatkowski: RMichael-Siatkowski@dmei.org Mind if we get a plug in here? We understand. Treating chronic dry eye shouldn't be complicated, painful or expensive. We're confident our new VeraPlug™ is going to give you a fresh perspective on patient care. Lacrivera. You'll want to keep an eye on us. A F R E S H P E R S P E C T I V E ™ © 2014 Lacrivera. All rights reserved. 2500 Sandersville Rd ■ Lexington KY 40511 USA lacrivera.com ( 855 ) 857-0518 Get a fresh perspective at booth #506 Mind Mind a plug if we get Mind a plug if we get Mind a plug if we get in here a plug in here a plug ? in here a plug give you a fresh perspective on patient care 're confident our new e W 't be complicated, painful or expensive shouldn e unde We understand. give you a fresh perspective on patient care eraPl Ve 're confident our new 't be complicated, painful or expensive reating chronic dry eye T e understand. . give you a fresh perspective on patient care ™ is going to eraPlug . 't be complicated, painful or expensive reating chronic dry eye acrivera. L A F R E S H P E R S P E C T I V E ™ eep an eye on us. ou'll want to k Y You'll want to k acrivera. A F R E S H P E R S P E C T I V E ™ eep an eye on us. Review continued from page 89 Fenway Park, home of the Boston Red Sox, is the oldest original Major League Baseball park still in use. Source: www.cityofboston.gov February 2014 84-90 Residents_EW February 2014-DL2_Layout 1 1/30/14 3:42 PM Page 90

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