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. 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.
Vámosi
P
P
University Medical School of Debrecen, Department of Ophthalmology, Hungary.
Sohajda
Z
Z
Módis
L
L
Vámosi
G
G
Berta
A
A
D000328:Adult; D003315:Cornea / Q000033:anatomy & histology*; D006801:Humans; D015588:Observer Variation; D009885:Ophthalmology / Q000295:instrumentation*; D015203:Reproducibility of Results; D013690:Television