[Accuracy and reproducibility of the Eyesys corneal topographic analysis system]

Corneal topographic analysis has become quite useful for corneal surgery. Quantitative data on the quality and accuracy of the available instruments are not well known. We studied the accuracy and the reproducibility of the Eyesys machine using 4 calibrated balls: 8.99 mm, 7.93 mm, 7.10 mm, 6.13 mm. The machine is accurate (precision less than 0.1D for all the balls) and reproducible (4 measurements) with a SD less than 0.05 diopter for all the balls except for the 55.04's ball (0.06 to 0.1). We also studied reproducibility with six normal corneas using the same method. SD was 0.26 diopter for keratometry and 0.50 diopter for the astigmatism value.