Vinicius S De Stefano1, Ibrahim Seven1, J Bradley Randleman1, William J Dupps2. 1. From the Cole Eye Institute (De Stefano, Seven, Dupps) and the Department of Biomedical Engineering (Dupps), Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, and the Keck School of Medicine (Randleman) and the Roski Eye Institute (Randleman), University of Southern California Los Angeles, Los Angeles, California, USA; Ophthalmology (De Stefano), Federal University of São Paulo, São Paulo, Brazil. 2. From the Cole Eye Institute (De Stefano, Seven, Dupps) and the Department of Biomedical Engineering (Dupps), Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, and the Keck School of Medicine (Randleman) and the Roski Eye Institute (Randleman), University of Southern California Los Angeles, Los Angeles, California, USA; Ophthalmology (De Stefano), Federal University of São Paulo, São Paulo, Brazil. Electronic address: bjdupps@outlook.com.
Abstract
PURPOSE: To assess the ability of air puff-derived biomechanical variables to predict surgeon-perceived candidacy for laser in situ keratomileusis (LASIK). SETTING: Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, and Emory Eye Institute, Emory University, Atlanta, Georgia, USA. DESIGN: Retrospective case series. METHODS: Data were collected from refractive surgery screening examinations by 2 surgeons at 2 centers. Disqualified cases (19 eyes and 28 eyes from each surgeon) were judged not to be candidates based on available data including standard variables from the Ocular Response Analyzer. Controls consisted of LASIK candidates (n = 26 and 23). Three custom biomechanical variables not available during screening were calculated and compared by group and surgeon. RESULTS: The hysteresis loop area was significantly different between disqualified cases and controls for both surgeons (Surgeon 1: controls, 121.50 ± 25.38 [SD], disqualified, 107.62 ± 18.50, P = .04; Surgeon 2: controls, 135.89 ± 22.47, disqualified, 106.11 ± 16.40, P < .001). The area under the curves of the receiver operating characteristics and the cutoff values were statistically significant for the concavity minimum and hysteresis loop area for Surgeon 1 and for all variables except concavity minimum for Surgeon 2. The hysteresis loop area had the highest odds ratio (Surgeon 1, 4.48, Surgeon 2, 20.00). Adjusted R2 in best-subsets regressions were 40.2% for Surgeon 1 and 62.9% for Surgeon 2. CONCLUSIONS: The hysteresis loop area was predictive of which patients were disqualified for LASIK at different sites. Certain measures of the corneal dynamic response to an air puff might serve as correlates to clinically perceived ectasia risk.
PURPOSE: To assess the ability of air puff-derived biomechanical variables to predict surgeon-perceived candidacy for laser in situ keratomileusis (LASIK). SETTING: Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, and Emory Eye Institute, Emory University, Atlanta, Georgia, USA. DESIGN: Retrospective case series. METHODS: Data were collected from refractive surgery screening examinations by 2 surgeons at 2 centers. Disqualified cases (19 eyes and 28 eyes from each surgeon) were judged not to be candidates based on available data including standard variables from the Ocular Response Analyzer. Controls consisted of LASIK candidates (n = 26 and 23). Three custom biomechanical variables not available during screening were calculated and compared by group and surgeon. RESULTS: The hysteresis loop area was significantly different between disqualified cases and controls for both surgeons (Surgeon 1: controls, 121.50 ± 25.38 [SD], disqualified, 107.62 ± 18.50, P = .04; Surgeon 2: controls, 135.89 ± 22.47, disqualified, 106.11 ± 16.40, P < .001). The area under the curves of the receiver operating characteristics and the cutoff values were statistically significant for the concavity minimum and hysteresis loop area for Surgeon 1 and for all variables except concavity minimum for Surgeon 2. The hysteresis loop area had the highest odds ratio (Surgeon 1, 4.48, Surgeon 2, 20.00). Adjusted R2 in best-subsets regressions were 40.2% for Surgeon 1 and 62.9% for Surgeon 2. CONCLUSIONS: The hysteresis loop area was predictive of which patients were disqualified for LASIK at different sites. Certain measures of the corneal dynamic response to an air puff might serve as correlates to clinically perceived ectasia risk.
Authors: David Touboul; Antoine Bénard; Ashraf M Mahmoud; Anne Gallois; Joseph Colin; Cynthia J Roberts Journal: J Cataract Refract Surg Date: 2011-10-05 Impact factor: 3.351