Purpose:
To evaluate the agreement between Rebound Tonometer (RBT), OcularResponse Analyzer (ORA), Dynamic Contour Tonometer (DCT) andGoldmann applanation tonometer (GAT) in measuring intraocularpressure (IOP), and the influence of the corneal propertieson the difference in IOP measurements between these tonometers.
Methods:
A total of 57 eyes of 18 healthy individuals and 39 glaucomapatients were included. Central corneal thickness (CCT) wasobtained using ultrasonic pachymetry (mean of 3 measurements)and keratometry (central corneal curvature) readings were basedon the automated keratometry. Corneal hysteresis (CH) was obtainedusing the ORA. IOP measurements were taken using iCare RBT (meanof 6 readings), corneal-compensated ORA IOP (mean of 4 readings),Pascal DCT (mean of 2 readings) and GAT (mean of 2 readings)in random order with an interval of 10 minutes among the devices.
Results:
The mean (SD) IOP obtained with RBT, ORA, DCT and GAT was 15.2(6.5) mmHg, 18.7 (6.8) mmHg, 16.5 (3.9) mmHg and 15.3 (5.7)mmHg respectively. The mean (SD) CCT was 538.2 (37.9) µm.The mean (SD) keratometry was 44.35 (1.64) diopters. The mean(SD) CH was 9.00 (1.72) mmHg. The agreement between tonometersis shown in Table 1. The correlation between differences inIOP measurements and corneal properties is shown in Table 2.
Conclusions:
Poor agreement was found between tonometers. The CCT was correlatedwith the difference between RBT and DCT measurements, and betweenDCT and GAT measurements. The CH is correlated with the differencebetween RBT and GAT measurements.
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: systems/equipment/techniques • cornea: basic science