Comparison of keratometric values of healthy and diseased eyes measured by Javal keratometer, EyeSys and PAR CTS

Purpose. To compare the simulated keratometric results of the PAR CTS and the EYESYS corneal imaging systems to the Javal keratometer in healthy eyes, in keratoconus eyes and in eyes after corneal grafting. Methods. Patients treated on the Cornea Service were divided into three groups (keratoconus; 6-12 months post keratoplasty; and normal corneas), and measured with each of the three instruments. Keratometry results, and ease of obtaining the results, were collected. Results. Eighteen normal corneas, 10 transplanted corneas and 16 keratoconus corneas were examined. Average astigmatism estimated by the EyeSys was lower by 0.71, 1.19 and 0.16 diopters than that measured by the Javal keratometer. The corresponding values for the PAR were 0.06, 0.04 and -0.04 diopters. EyeSys axis estimates were 14.1, 18.9 and 5.8 degrees away from the Javal keratometric results, while PAR axis estimates were different by 23.2, 27 and 23.4 degrees. The number of tries needed to obtain a satisfactory image was 1.4, 2.1 and 2.1 times with the EyeSys and 1.1, 1.4 and 1.2 times with the PAR. Conclusions. The PAR CTS was easier to use than the EyeSys and seemed to estimate astigmatism power bet er. The EyeSys tended to estimate the axis of astigmatism better than the PAR.