Comparison of corneal power, XXXX , and wavefront aberration measurements obtained by a point-source color light-emitting diode-based topographer, a  Placido-disk topographer, and a combined Placido and dual Scheimpflug device.

@entity940 @entity772
PURPOSE: To evaluate and compare the performance of a point-source color light-emitting diode (LED)-based topographer (color-LED) in measuring anterior corneal power and aberrations with that of a Placido-disk topographer and a combined Placido and dual Scheimpflug device. SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas USA. DESIGN: Retrospective observational case series. METHODS: Normal eyes and post-refractive-surgery eyes were consecutively measured using color-LED, Placido, and dual-Scheimpflug devices. The main outcome measures were anterior corneal power, @entity940 , and higher-order aberrations (HOAs) (6.0 mm pupil), which were compared using the t test. RESULTS: There were no statistically significant differences in corneal power measurements in normal and post-refractive surgery eyes and in @entity940 magnitude in post-refractive surgery eyes between the color-LED device and Placido or dual Scheimpflug devices (all P > .05). In normal eyes, there were no statistically significant differences in 3rd-order @entity772 and 4th-order spherical aberration between the color-LED and Placido devices and in HOA root mean square, 3rd-order @entity772 , 3rd-order trefoil, 4th-order spherical aberration, and 4th-order secondary @entity940 between the color-LED and dual Scheimpflug devices (all P > .05). In post-refractive surgery eyes, the color-LED device agreed with the Placido and dual-Scheimpflug devices regarding 3rd-order @entity772 and 4th-order spherical aberration (all P > .05). CONCLUSIONS: In normal and post-refractive surgery eyes, all 3 devices were comparable with respect to corneal power. The agreement in corneal aberrations varied. FINANCIAL DISCLOSURE: Drs. Wang, Koch, and Weikert are consultants to Ziemer Ophthalmic Systems AG. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Surgical, Inc., and i-Optics  Corp.
