Abstract
Purpose :
To assess the ability of air-puff derived measures of biomechanical behavior to predict clinical decisions on refractive surgery candidacy.
Methods :
Data were retrospectively collected from consecutive refractive surgery screening exams by two surgeons from different academic centers (Cleveland Clinic Cole Eye Institute (CC) and Emory Eye Center (EEC)). Only right eyes were analyzed. The disqualified subject groups consisted of 19 (CC) and 28 (EEC) eyes and included subjects who were disqualified as candidates based on clinical impression after reviewing available clinical, topo/tomographic (Placido and Scheimpflug), and biomechanical data (Ocular Response Analyzer (ORA)). Control groups consisted of eyes deemed clinically to be safe candidates for LASIK (n=26 (CC) and 23 (EEC)). Keratometric and pachymetric data from the Pentacam were compared for each group. While standard ORA variables were available to surgeons at the time of the decision, the 3 investigator-derived variables (Table 1, previously described by Hallahan et al, Ophthalmol 2014) were calculated retrospectively and surgeons were effectively masked to them. Comparisons were performed using t-tests for independent samples.
Results :
Anterior curvature and corneal thickness data were significantly different between groups (Table 1). Hysteresis loop area (HLA) was the only biomechanical variable that was significantly different between disqualified and control subjects across both centers (Table 2).
Conclusions :
Across two clinical sites, a custom biomechanical variable, HLA, was predictive of which refractive surgery screening patients were selected for LASIK and which were disqualified. Certain measures of the corneal dynamic response to an air puff may serve as objective correlates to clinically perceived risk of ectasia.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.