Comparison of Icare, dynamic contour tonometer, and ocular response analyzer with goldmann applanation tonometer.

Abstract

Abstract Purpose: To compare the intraocular pressure (IOP) readings taken with the ICare tonometer, the Pascal Dynamic Contour Tonometer (DCT), and the Ocular Response Analyzer (ORA) with the Goldmann Applanation Tonometer (GAT). To evaluate the influence of central corneal thickness (CCT) on the IOP measurements. Methods: In a prospective study 93 eyes of 93 patients attending the glaucoma clinic were examined. Patients were randomly divided into four groups to vary the order in which the tonometers were applied. CCT was measured with an ultrasound pachymeter (Pachmate). A multivariate normal model was used to compare the mean IOP measurements between the four instruments. Spearman correlation coefficients were used to assess the correlation between IOP measurements and CCT. Bland‐Altman plots were used to assess the agreement between the tonometry methods. Results: The average CCT was 558 ±47.4 μm. The mean IOP for GAT, ICare, DCT, and ORA (Goldmann correlated IOP) were 15.1 ±4.8, 15.7 ±5.7, 18.3 ±5.1, and 18.3 ±6.6 mmHg respectively. There was no significant difference between the mean IOP obtained with GAT and ICare (p=0.44), nor between DCT and ORA (p=0.99). There was no correlation between the IOP measurements and CCT for the four instruments. Bland‐Altman graphs show disagreement between the measurements taken by the four tonometers. Conclusions: IOP readings from ICare are in accordance with those from GAT, whereas DCT readings correspond well to (Goldmann correlated) ORA measurements. DCT and ORA readings both overestimate IOP measured with GAT.