Comparison of intraocular pressure measurements and assessment of intraobserver and interobserver reproducibility with the portable ICare rebound tonometer and Goldmann applanation tonometer in glaucoma patients.

Objective: The goals of our study were to analyze the correlation of rebound tonometer (RBT) and Goldmann applanation tonometer (GAT), assess the intraobserver and interobserver reproducibility of these tonometers, and investigate the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements recorded with both tonometers in glaucoma patients under treatment.

Methods: In a prospective study of 65 eyes with glaucoma, IOP was measured using RBT and GAT, followed by measurements of CCT.

Results: A clear correlation between RBT and GAT was found (r=0.89, P<0.001). Bland-Altman analysis showed a mean difference of measurements by GAT and RBT of 2.45 mm Hg with 2 SD=4.24 mm Hg. Both tonometers were affected by CCT. High intraobserver correlation coefficients were found with both tonometers (0.981 and 0.979 for RBT for examiner 1 and examiner 2, respectively, and 0.989 for GAT for both examiners). Interobserver agreement appeared to be better with GAT when compared with RBT (variation coefficients were 4.6% for GAT and 7.1% for RBT).

Conclusions: RBT may have a potential role and use in routine evaluation and management of glaucoma patients given its high correlation with GAT and high reproducibility in IOP measurements. As with GAT, measurements obtained with RBT are affected by CCT, reinforcing the role of pachymetry in glaucoma management.