Advantages and disadvantages of the iCare tonometer: prospects for medical use

BACKGROUND: Ophthalmic tonometers are instruments used for the measurement of intraocular pressure in the diagnosis and monitoring of conditions in which the level of intraocular pressure deviates from the individual norm. One such tonometer is the iCare, which operates on the rebound principle [1]. A small rod is directed towards the cornea, the nature of its movement is analyzed, and the device calculates the intraocular pressure [1, 2]. The use of rebound technology for the advancement of a portable eye tonometer will facilitate the development of a convenient, accurate, and reliable device for the measurement of intraocular pressure.

AIM: The aim of this study is to identify the principal advantages and disadvantages of the iCare ophthalmic tonometer, with a view to facilitating the further development of a Russian analogue.

MATERIALS AND METHODS: The authors conducted a comprehensive literature review, searching for relevant publications in PubMed, Web of Science, Scopus, and eLibrary databases from 2005 to 2023. The search terms used were “rebound tonometry”, “iCare tonometry”, and “intraocular pressure”. A total of 17 scientific articles were analyzed.

RESULTS: The main advantages of the iCare tonometer are highlighted:

• No patient discomfort due to minimal corneal contact time, no anesthesia required [1, 2];
• The accuracy of the indicators measured by the iCare tonometer is comparable to the gold standard of intraocular pressure measurement, the Goldmann tonometer [3, 4, 6];
• Portability and compactness of the tonometer, ability to measure pressure in a sitting or lying position [1, 2];
• Intraocular pressure measurement takes little time [1, 16, 17];
• The use of a disposable handpiece minimizes the risk of infectious disease transmission [16];
• Possibility to measure intraocular pressure in eyes with various pathologies, such as glaucoma, keratoconus [9, 10], post-refractive surgery [11] and keratoplasty [8, 12, 13], vitreous cavity tamponade with silicone [14];
• The iCare tonometer does not require regular maintenance and calibration, is easy to use, and can be used by other professionals and patients at home [16, 17].

Disadvantages include:

• High cost compared to other tonometers, requiring regular purchase of disposable probes [15, 17];
• The limited use of the iCare tonometer in patients with corneal abnormalities, namely patients with an abnormal corneal resistance factor or corneal hysteresis [5, 7].

CONCLUSIONS: The iCare tonometer offers a number of advantages, including patient safety and comfort during the examination, accuracy, portability, quick results, and the ability to be used on healthy eyes as well as on eyes with various diseases or after surgery. However, it also has some limitations when used in certain clinical cases, as well as a high cost. Despite these limitations, the iCare tonometer remains a valuable tool for measuring intraocular pressure. Therefore, we propose to use the rebound technology employed in the iCare tonometer to develop a domestic portable tonometer.