Comparison between Goldmann, Icare Pro and Corvis ST tonometry

Abstract

PurposeTo compare intraocular pressure (IOP) between the new non-contact tonometer Corvis ST (CST), the Goldmann applanation tonometry (GAT) and Icare Pro rebound tonometer (PRO). MethodsA total of 178 eyes of 178 healthy subjects were selected for the study. Measurements of IOP were made in a random order with GAT, PRO and CST. Central corneal thickness (CCT) was determined by ultrasound pachymetry. The mean of three valid measurements of each variable was used in the statistical analysis. The relationship between the tonometers was established using Bland–Altman plots. ResultsMean IOP was 15.5±2.8mmHg for GAT, 15.4±2.8mmHg for CST, and 14.6±2.3mmHg for PRO. The mean differences between pairs of tonometers were: GAT-PRO=0.9±1.7mmHg (p<.001), GAT-CST: 0.1±2.2 (p=.398), and PRO-CST: −0.8±−0.7mmHg, p<0.001. A positive relationship was detected between CCT and the three tonometers: GAT: r=0.325, p<.001; PRO: r=0.385, p<.001, and CST: r=0.428; p<.001. ConclusionsThe differences found between PRO and GAT were significantly higher than those found between CST and GAT, which showed non-significant differences. The measurements of the three tonometers were affected by the CCT.