FREQUENTLY ASKED QUESTIONS

WHY DOES THE TONOVET NOT REQUIRE CALIBRATION? 

iCare rebound tonometers do not require calibration or routine servicing. The only component that needs periodic maintenance in the clinic is the probe base, which, over time, can collect dust and particles that may interfere with its movement. Users should clean or replace the probe base following the guidelines provided in the user manual. 

If there are any doubts about the measurement results, the calibration can be checked. In such cases, it's advisable to contact your local dealer or distributor. Additionally, if the tonometer has been dropped and requires servicing, please reach out to your local dealer or distributor for further instructions.  

IS THE TONOVET MEASUREMENT PAINLESS? 

The measurement is painless. A light-weight probe touches the cornea momentarily. Most patients do not even notice the measurement.   

IS THE TONOVET MEASUREMENT RESULT ACCURATE?   

Numerous independent studies have verified the accuracy of TONOVET readings. Extensive bench testing and clinical trials have also been conducted to confirm both the accuracy and repeatability of the measurements. It is important to note that improper handling can significantly raise intraocular pressure (IOP). Therefore, avoid using excessive restraint on the patient or applying too much pressure around the eye area.  

WHAT ARE THE CAUSES OF INCREASED IOP VALUES TO A HEALTHY-LOOKING EYE?   

Excessive restraint of the patient or the patient looking to the side can compress the jugular vein(s). A collar that is too tight can lead to abnormally high intraocular pressure (IOP) values. Additionally, applying too much pressure around the eye, such as manually holding the eyelids open, can also contribute to increased IOP. The patient's stress level can elevate IOP as well. Early-stage glaucoma, which may not present any ocular symptoms, can be detected through abnormally high IOP readings. Generally, IOP decreases with age. In dogs, diurnal variation causes changes in IOP, with levels peaking in the morning and gradually declining throughout the day. Conversely, it has been suggested that the opposite pattern may occur in cats and rabbits.  

WHY SIX MEASUREMENTS? 

To obtain accurate measurement results using the TONOVET Plus, six measurements must be taken in a single sequence. The TONOVET Plus software automatically discards the highest and lowest readings, and the final result is the average of the four remaining measurements.   

Similarly, the TONOVET Pro can also take six sequential measurements, like the TONOVET Plus. Additionally, it features a Quick Measure option, which calculates an intraocular pressure (IOP) measurement based on an average of only 2 to 3 sequential readings. Please note that when using the Quick Measure setting, the alignment assistance feature on the TONOVET Pro is automatically disabled.  

SHOULD BOTH EYES BE MEASURED?   

When possible, both eyes should always be measured for adequate information comparison.    

ADVICE FOR TONOVET PLUS LEFT-HANDED USERS.   

TONOVET Plus is used by left-handed customers. During the measurement, it is most important not to look at the display, but to concentrate on the probe's distance from the eye. We say this to all customers regardless of their preferred hand to use. Red/green lights will guide you in positioning the probe correctly. The sound will inform you when the IOP measurement is finished. Also, a customer can swing TONOVET Plus, so the display is facing upwards. Alternatively, the TONOVET Pro has a screen on the back of the unit, facing the user. We still advise that during the measurement, you concentrate on the probe’s distance from the eye and not the display.   

ENVIRONMENTAL CONDITIONS, SPECIFICALLY HUMIDITY, TEND TO AFFECT THE PERFORMANCE OF MY DEVICE, AND THE PROBE DOES NOT SEEM TO MOVE AS IT SHOULD. 

In colder temperatures or high humidity, it is recommended to remove the tonometer from its case to allow it to acclimate to the current environmental conditions. If it is used immediately, especially in humid environments, condensation may be present in the probe base, which can interfere with its movement. This condensation will dissipate within a few minutes if the tonometer is allowed to adjust to its surroundings.  

CAN TOPICAL ANESTHESIA STILL BE USED? 

The iCare TONOVET rebound tonometer is designed for use without the need for a topical anesthetic. The lightweight probe touches the eye so gently that most patients hardly blink in response. For the most accurate measurements, we recommend avoiding the application of a topical anesthetic. While it is possible to measure an anesthetized eye, the readings may be slightly influenced by the swelling caused by the anesthetic. However, this effect is typically minimal, usually less than 2 mmHg.  

DO CERTAIN ANESTHETIC AGENTS OR SEDATIVES AFFECT IOP MORE THAN OTHERS?   

Most anesthetics and sedatives tend to lower intraocular pressure (IOP), while some others may increase it. Medications that help reduce anxiety before an eye examination can be appropriate. However, a veterinary ophthalmologist can recommend the most suitable medication based on the specific needs of the pet. 

CAN HANDLING THE PATIENT AFFECT THE IOP?   

Yes, it can significantly increase the IOP. Excessive restraining of the patient should be avoided, and if the eye needs to be held open, be careful not to add any pressure to the eyeball. If a collar is worn, make sure it is not too tight or remove the collar for the measurement. Pressure around the neck (jugular veins compressed) increases IOP. Measuring should always be done so that the patient is looking straight ahead in a natural, relaxed position. Even if the head is tilted sideways for measuring, it can affect the IOP and cause it to increase.   

WHAT ARE THE NORMAL IOP RANGES FOR USING TONOVET?    

‘Normal’ range is intended to serve as a general guideline only and should always be interpreted in the context of other visual findings. There is no sharp cut-off value between a healthy and a diseased eye. Tonometry should be performed in both eyes. The values of IOP should be within 5 mmHg between healthy eyes of the same subject.  (see page 11- we need to update this page #) 

WHAT SETTING SHOULD I USE TO MEASURE A SPECIES NOT INCLUDED IN THE TONOVET CALIBRATIONS?

Whenever measuring an animal for which we do not have a specific calibration, it is up to the user to choose the setting and analyze the results. We cannot recommend anything that we do not have validation for. Although our species settings are calibrated for the cat, dog, rabbit, horse, mouse, and rat, our tonometers are widely used on several other species. As a rule of thumb, we recommend using the setting (calibration) closest to the eye size, with some restrictions: the cat setting should always be used on felines only.    

WHICH TONOMETER IS EASIER TO USE ON HORSES? 

The TONOVET Plus and Pro are more user-friendly for measuring horses compared to the original TONOVET, which struggled to measure at a downward angle due to the probe ejecting from the device. The TONOVET Plus allows for horizontal positioning, along with slight upward and downward adjustments. Meanwhile, the TONOVET Pro offers 200 degrees of positional freedom and probe release control, making it even easier to position for measuring horses.  

IF THE EYE HAS DISCHARGE, CAN YOU DO A SALINE WASH BEFORE THE MEASURING OR WILL THAT AFFECT THE TEST? 

KCS (Dry Eye) and severe ocular inflammation can cause a sticky surface, which should always be washed with a sterile eye wash before measuring. Discharge might affect the bounce of the probe, which can affect the reading. Saline washes will not affect the reading.   

CAN AN EYE WITH AN ULCER BE MEASURED, AND HOW MUCH ACUTE ULCERS CAN AFFECT THE IOP?   

A measurement should not be taken when a cornea has weakened tissues, as with deep and/or infected ulcer, a corneal perforation, or a descemetocele.  This can cause the eye to rupture/perforate.  Even gentle eyelid manipulation can cause a weakened cornea to perforate.   

CAN PROBES BE REUSED?  

To ensure safe and reliable measurements, the probe is designed for single use only. Probes should never be cleaned or sterilized, as these processes can damage the probe and result in unreliable measurements or even harm to the tonometer. However, the same probe can be used for measuring the same patient within a short period. 

DO ALL TONOVET TONOMETERS USE THE SAME PROBES?

All TONOVET tonometers use the same standard probes, except the TONOLAB, which requires specially designed probes.