A comparison of the Canon TX-20P™ non-contact tonometer and pachymeter in healthy eyes

Abstract

Background: The aim of this study was to compare the intraocular pressure (IOP) and the central corneal thickness (CCT) measurements obtained with the Canon TX-20P™ with IOP measured with Goldmann applanation tonometer (GAT) and the CCT measured with ultrasound (US) pachymetry in healthy eyes. Methods: Thirty one healthy voluntary subjects participated in the study, age ranging from 16 to 81 years (mean age 50.9 years). In total 58 eyes were selected for analysis. All measurements were performed by the same examiner. The measurements were taken in the same order in all subjects: Canon IOP and CCT, Goldmann IOP and US CCT. Results: A strong correlation was found between IOP for both CCT compensated and raw values (R2 0.79 and 0.71 respectively) and CCT (R2 0.80) readings from GAT and US pachymetry as compared with the Canon TX-20P™, however, a small but statistically significant difference was found in both IOP and CCT measurements. Conclusions: The Canon TX-20P™ is a compelling two-in-one non-invasive instrument that allows both IOP and CCT measurements. The Canon TX-20P™ has acceptable agreement for IOP measurements, especially the CCT compensated IOP, as compared with GAT and for CCT when compared with US in healthy subjects. However, it remains to be evaluated if such an agreement can be found in subjects with abnormal IOP and CCT.