Evaluation of keratometry with a novel Color-LED corneal topographer

PURPOSE: To assess the performance of a novel keratometer based on reflections of colored light-emitting diodes (LEDs) and compare it with devices based on Placido rings, monochromatic LEDs, and Scheimpflug images.

METHODS: Sixty-three eyes of 63 patients with virgin corneas underwent keratometry with color-LED corneal topography (Cassini; i-Optics, The Hague, The Netherlands) and with devices based on Placido ring reflections (Keratron; Optikon, Rome, Italy), monochromatic LED reflections (Lenstar; Haag-Streit, Koeniz, Switzerland), and Scheimpflug imaging (Pentacam; Oculus Optikgeräte, Wetzlar, Germany). Three repeated measurements were performed with each device. Comparability and repeatability of corneal power and cylinder measurements were assessed. The Bonferroni-corrected α-threshold for statistical significance was 0.016.

RESULTS: Corneal power measurements with the Cassini topographer were not statistically significantly different from those with the Pentacam (P = .64). They were statistically significantly lower than those with the Keratron and Lenstar (P < .01), but the differences were of negligible clinical relevance. Cylinder measurements with the Cassini topographer were not statistically significantly different from those with any other device (P = .46). Repeatability of Cassini corneal power measurements was not statistically significantly different from that of the Keratron (P = .02), but was statistically significantly lower than that of the Lenstar and Pentacam (P < .001). Repeatability of Cassini cylinder measurements was statistically significantly higher than that of the Pentacam and Keratron (P < .001), but was not statistically significantly different from that of the Lenstar (P > .05).

CONCLUSIONS: Corneal power and cylinder measurements with color-LED corneal topography yielded values that were comparable to those of other commonly used devices. Repeatability of corneal power measurements was lower compared to some devices, but repeatability of cylinder measurements was relatively high. This may be of particular interest when using toric intraocular lenses.