Comparison of the ICare® rebound tonometer with the Goldmann tonometer in a normal population

• Published in: Ophthalmic & physiological optics Vol. 25; no. 5; pp. 436 - 440
• Main Authors: Fernandes, P., Díaz-Rey, J. A., Queirós, A., Gonzalez-Meijome, J. M., Jorge, J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.09.2005; Blackwell
• Subjects: Adolescent; Adult; applanation tonometry; Biological and medical sciences; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; Humans; impact tonometry; induction; Intraocular Pressure; IOP; Male; non-contact tonometry; rebound tonometer; Reference Values; Reproducibility of Results; Tonometry, Ocular - instrumentation; Vertebrates: nervous system and sense organs; Induction; IOP; Normal; non-contact tonometry; Applanation tonometry; Contact; Tonometer; impact tonometry; rebound tonometer; Rebound; Ophthalmology; Comparative study; Intraocular pressure
• ISSN: 0275-5408; 1475-1313
• DOI: 10.1111/j.1475-1313.2005.00327.x

The aim of this study was to evaluate the accuracy of measurement of intraocular pressure (IOP) using a new induction/impact rebound tonometer (ICare®) in comparison with the Goldmann applanation tonometer (AT). The left eyes of 46 university students were assessed with the two tonometers, with induction tonometry being performed first. The ICare® was handled by an optometrist and the Goldmann tonometer by an ophthalmologist. In this study, statistically significant differences were found when comparing the ICare® rebound tonometer with applanation tonometry (AT) (p < 0.05). The mean difference between the two tonometers was 1.34 ± 2.03 mmHg (mean ± S.D.) and the 95% limits of agreement were ±3.98 mmHg. A frequency distribution of the differences demonstrated that in more than 80% of cases the IOP readings differed by <3 mmHg between the ICare® and the AT. In the present population the ICare® overestimates the IOP value by 1.34 mmHg on average when compared with Goldmann tonometer. Nevertheless, the ICare® tonometer may be helpful as a screening tool when Goldmann applanation tonometry is not applicable or not recommended, as it is able to estimate IOP within a range of ±3.00 mmHg in more than 80% of the population.