gms | German Medical Science

102. Jahrestagung der DOG

Deutsche Ophthalmologische Gesellschaft e. V.

23. bis 26.09.2004, Berlin

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Pentacam vs. Keratograph: comparison of keratometry of normal eyes and eyes with corneal pathology

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  • corresponding author C. Kojetinsky - Department of Ophthalmology of Ludwig-Maximilians-University München, München
  • C.-A. Lackerbauer - Department of Ophthalmology of Ludwig-Maximilians-University München, München
  • M. Grueterich - Department of Ophthalmology of Ludwig-Maximilians-University München, München
  • A. Kampik - Department of Ophthalmology of Ludwig-Maximilians-University München, München

Evidenzbasierte Medizin - Anspruch und Wirklichkeit. 102. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft. Berlin, 23.-26.09.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dogP 051

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dog2004/04dog542.shtml

Published: September 22, 2004

© 2004 Kojetinsky et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

Text

Objective

The Pentacam, a new measurement tool, can also be used for keratometry. In contrast to the common used Keratograph (based on Placido rings), measurements are based on Scheimpflug imaging. Up to now there is no generally accepted way how to interprete the results of the Pentacam. Therefore we investigated the correlation of keratometry data between both tools (Oculus Optikgeräte GmbH, Wetzlar, Germany).

Methods

First the horizontal and vertical K-readings (Khoriz bzw. Kvertic) [D] were measured by Keratograph (version: 2,50) und Pentacam (version: 2,57) in 101 normal eyes and 63 eyes with corneal pathology. The mean differences of the results of both tools were calculated and statistically analysed. Second, different measuring modes available for the Pentacam were compared (50 eyes): 12 vs. 25 pictures per eye. Analysis was performed as described.

Results

The mean difference between Khoriz(Keratograph) and Khoriz(Pentacam) in the group of normal eyes was 0,83± 0,42 D and for Kvertic 0,95± 0,52 D, which was statistically significant (p<0,005; Mann-Whitney Rang Sum Test). Concerning the eyes with corneal pathologies the differences were 0,99± 0,98 D (Khoriz) and 1,38± 1,76 D (Kvertic) resp. (no statistically significance). The Keratograph reveal higher K-readings compared to the Pentacam in 87,1% of the normal eyes (Khoriz aswell as Kvertic), and in 76,2% (Khoriz) and 81,0% (Kvertic) of pathological corneas. The mean difference between the two measurement modes of the Pentacam was 0,44± 0,41 D (Khoriz) resp. 0,52± 0,68 D (Kvertic) (no statistically significance: paired t-test, p=0,7792 resp. p=0,8954). Using 25 pictures per eye the K-readings were higher than in the 12 picture mode in 60,0% of the eyes.

Conclusions

In this first published comparison of keratometry data between Keratograph and Pentacam lower K-readings were obtained by the latter method. We assume that this difference is due to the fact that the posterior curvature of the cornea is considered in the algorithm of the Pentacam but not in the one of the Keratograph. Additionally the possible differences in K-readings in varying measurement modes need further investigations.