Comparison of the IOPen® and iCare® rebound tonometers with the Goldmann tonometer in a normal population

• Published in: Ophthalmic & physiological optics Vol. 30; no. 1; pp. 108 - 112
• Main Authors: Jorge, J., Fernandes, P., Queirós, A., Ribeiro, P., Garcês, C., Gonzalez-Meijome, J. M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2010
• Subjects: Adult; Aged; Aged, 80 and over; applanation tonometry; Female; Humans; iCare; impact tonometry; induction; Intraocular Pressure; IOPen; Male; Middle Aged; Ocular Hypertension - diagnosis; rebound tonometer; Statistics, Nonparametric; Tonometry, Ocular - instrumentation; Tonometry, Ocular - standards; Young Adult
• ISSN: 0275-5408; 1475-1313
• DOI: 10.1111/j.1475-1313.2009.00697.x

This study proposes to evaluate the level of accuracy of intraocular pressure (IOP) measurements of a second generation rebound tonometer (IOPen®), taking as references the Goldmann Applanation Tonometer (GAT) and the iCare® rebound tonometer. The right eyes of 101 consecutive clinical patients were assessed with the three tonometers. The IOPen® and iCare® measurements were taken by two different optometrists and the GAT by an ophthalmologist. In this study, statistically significant differences were found when comparing the IOPen® tonometer with the other two tonometers (p < 0.001). The IOPen® underestimated the IOP value when compared to the GAT and the iCare® (mean differences were 2.94 ± 4.65 mmHg and 3.20 ± 4.72 mmHg (mean ± S.D.), respectively). The frequency distribution of differences demonstrated that in more than 55% of measurements the IOP readings differed by more than 3 mmHg between the IOPen® and the GAT. Based on the present population study, these results suggest that IOPen® measurements should be interpreted with caution.