Abstract
Purpose :
To identify corneal variables and combinations that best differentiate normal corneas from the clinically unaffected eye from highly asymmetric keratoconic patients using a Placido-Dual Scheimpflug analyzer.
Methods :
A total of 41 normal corneas of 41 subjects evaluated for LASIK were imaged preoperatively with a Placido-Dual Scheimpflug system (Galilei G4, Ziemer, Inc.) and compared to 25 contralateral topographically normal eyes of clinically evident keratoconus in the fellow eye. The posterior surface, anterior surface and high order aberration variables measured were compared between the two groups using Student two-sample t test. Discriminating ability of the variables independently and in combination with each other were compared by receiver operator characteristics curves (ROC).
Results :
The best discriminative variables were Anterior Elevation Best Fit Sphere (AEBFS) (AUC = 0.809 ) and Asphericity Asymmetry Index (AAI) (AUC = 0.799). Combining AEBFS and AAI with Total Coma and Trefoil achieved the highest AUC (0.902).
Conclusions :
Corneal measurements with a dual Scheimpflug Analyzer provides useful parameters for differentiating normal corneas from Subclinical keratoconus. A combination of anterior surface elevation, posterior surface asymmetry, and higher order aberrations provided the best differentiation between groups.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.