Abstract
Purpose :
To compare the difference and agreement of total corneal higher-order aberrations (HOAs) measurements in normal and keratoconic eyes using Scheimpflug and Dual Scheimpflug/Placido imaging systems.
Methods :
One hundred and five healthy eyes screened for refractive surgery and 50 eyes diagnosed with keratoconus were evaluated sequentially by Scheimpflug and Dual Scheimpflug/Placido devices. Differences, correlations, and agreement between values for total root mean square (RMS), trefoil, coma, and spherical aberration were analyzed and Bland-Altmann plots generated to assess agreement of total corneal HOAs between these two devices.
Results :
In normal eyes, total RMS, coma, and trefoil were significantly different between devices (p<0.001 for all), while spherical aberration values were not. There was moderate positive correlation between devices for trefoil, coma, and spherical aberration, and strong positive correlation for total cornea RMS. In keratoconic eyes, trefoil at 30 degrees, spherical aberration and total RMS were significantly different between devices (p<0.05), while trefoil at 0 degrees and total coma values were not. There was weak positive correlation between devices for trefoil, moderate positive correlation for horizontal coma, and for total cornea RMS, and strong positive correlation for vertical coma and spherical aberration.
Conclusions :
Scheimpflug and Dual-Scheimpflug/Placido imaging devices generated statistically different values for total cornea higher-order aberrations for normal and keratoconic eyes. While correlation between devices were moderate to strong and a reasonable agreement were found in normal eyes, keratoconic eyes showed limited correlations and wide limits of agreement.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.