Rebound tonometry measures intraocular pressure (IOP) by briefly propelling a small probe against the cornea and calculating IOP based on the probe’s deceleration upon contact. The Tono-Vera Tonometer (Reichert Technologies), which received US Food and Drug Administration 510(k) clearance last year, employs this technique but distinguishes itself with enhanced accuracy thanks to its patented ActiView positioning system. This camera-based feature displays a live color image of the eye along with visual alignment cues to ensure proper positioning (Figure 1). Once the device confirms alignment, it automatically captures the measurement, delivering consistent and reliable IOP readings.
Figure 1. The Tono-Vera’s proprietary ActiView positioning system enables the operator to confirm proper alignment before automatically capturing the intraocular pressure measurement, helping ensure consistent and reliable results.
A US Food and Drug Administration (FDA) clinical trial demonstrated that average Tono-Vera measurements matched Goldmann applanation tonometry (GAT) measurements within 1 mmHg on average.1 “Measuring off center or at an angle can significantly impact the accuracy and repeatability of rebound tonometry measurements,” explains David Taylor, director of business development for Reichert Technologies Inc, a business of Ametek, in Buffalo, New York. “The ActiView positioning system facilitates automatic measurement only at the mechanical center (apex) of the cornea. Operator technique cannot materially influence a reading’s accuracy.
“It was natural for Reichert to enter this growing segment; we saw a great opportunity to improve upon existing products in the market,” continues Taylor. “Handheld tonometry devices are increasingly desirable as practices seek to delegate testing to technician staff more than ever before. But variability in the measurements due to user technique was a significant concern.”
Clinical Uses
The Tono-Vera is suitable for both routine clinical practice and situations where portability is advantageous, such as screening programs, telemedicine applications, operating rooms, and potentially at-home monitoring, says Felipe A. Medeiros, MD, PhD, distinguished professor and vice chair of research at Bascom Palmer Eye Institute at the University of Miami School of Medicine, who performed research on the Tono-Vera.
“It’s particularly beneficial for patients who have difficulty undergoing GAT due to positioning challenges, such as those with limited mobility and children,” observes Dr. Medeiros, who says he evaluated the Tono-Vera Tonometer because he wanted to find a reliable, user-friendly device to measure IOP. “Given its ease of use and consistent agreement with standard tonometry methods, it’s a valuable tool for glaucoma physicians in outpatient settings and primary care environments.”
The Tono-Vera doesn’t require a topical anesthetic, making the measurement process much more comfortable for patients than GAT. The device is intuitive, and physicians and technicians can usually perform proper measurements with the device in just a few minutes, Taylor says. Also, because of its single-use probes, the tonometer doesn’t require high-level disinfection between patients, making it fast and convenient.
Tono-Vera has a rechargeable battery model that sits in a charging cradle, so it’s always ready to use. The cradle features a built-in probe dispenser, making it functional and convenient. There is also an AA battery model; the AA battery cartridge and the rechargeable battery are interchangeable.
Thoughtful Design
The tonometer’s lightweight and comfortable design enhances both clinician comfort and patient experience. The auto-measurement function enables users to measure both eyes without pressing any buttons, which can help prevent repetitive motion disorders.
The adjustable FlexiSoft Forehead rest is not only comfortable for the patient, but it also enables the Acti- View alignment system to work because the soft, compressible, rubber tip permits users to change the distance from the eye without needing to adjust the forehead rest in most instances. Three measurements are taken in less than 1 second.
Bluetooth connectivity allows for seamless data transfer to electronic health records or remote monitoring systems, facilitating integration into modern clinical workflows.
“As a rebound tonometer, the Tono-Vera doesn’t require anesthetic drops, is nearly silent, and almost imperceptible to the patient when the measurement occurs,” Taylor says. “Many patients prefer this methodology over other tonometry methods.”
“Having a reliable and accessible tool supports better disease monitoring and management, ultimately contributing to improved long-term care for glaucoma patients,” concludes Dr. Medeiros. GP
Reference
1. Niles CR, Crinzi AR, Bonaventura R, Taylor DA. Evaluation of agreement of IOP measurements by Tono-Vera tonometer to Goldmann applanation tonometry. Front Ophthalmol (Lausanne). 2024;4:1441343. doi:10.3389/fopht.2024.1441343