Comparison of different keratometers with the EyeSys videokeratoscope

We compared the accuracy and the reproducibility of the measurements using a Haag-Streit, a Shin-Nippon, and a Carl Zeiss keratometer and an EyeSys videokeratoscope. Two investigators performed 20 measurements on 3 calibrated steel balls and 5 measurements on 22 normal corneas with all instruments....

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Bibliographic Details
Published in:Acta ophthalmologica Scandinavica 1998-04, Vol.76 (2), p.158-164
Main Authors: Vámosi, Péter, Sohajda, Zoltán, Módis, László, Vámosi, György, Berta, András
Format: Article
Language:English
Subjects:
Adult
Cornea - anatomy & histology
Humans
Observer Variation
Ophthalmology - instrumentation
Reproducibility of Results
Television
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Summary:We compared the accuracy and the reproducibility of the measurements using a Haag-Streit, a Shin-Nippon, and a Carl Zeiss keratometer and an EyeSys videokeratoscope. Two investigators performed 20 measurements on 3 calibrated steel balls and 5 measurements on 22 normal corneas with all instruments. Calculating the accuracy of the measurements the limits of the 95% confidence intervals of the bias were determined. The accuracy was better than +/-0.1D for the keratometers, whereas it was better than +/-0.25D for the EyeSys videokeratoscope. The coefficient of reproducibility (1.96 x standard deviation) on test balls and corneas was smaller than 0.25D in the case of the Shin-Nippon and Carl Zeiss keratometers and the EyeSys videokeratoscope whereas it was between 0.25-0.5D in the case of the Haag-Streit keratometer. The Carl Zeiss keratometer was the best with respect to the accuracy and reproducibility of the measurements. Paired t-test was used to find possible significant differences between the results of the two investigators, but only clinically insignificant differences were found.
ISSN:1395-3907
1600-0420
DOI:10.1034/j.1600-0420.1998.760207.x