Choosing a Tonometer

Deciding whether to monitor your own Eye PressuresReichert 7CR

With self tonometry, the possibility of monitoring eye pressure at home is within every glaucoma patient's reach. And with intraocular pressure as the only current treatable risk factor for glaucoma, those with pre-glaucoma or glaucoma are wise to gather as much data as possible regarding the nature and behavior of their eye pressures. Currently, the practice of monitoring those who are glaucoma suspects (ocular hypertension or OHT) and glaucoma patients entail only receiving routine eye pressure checks at their doctor's office or clinic. It is known by us in the Fiteyes community who test via self tonometry, and by the many studies showing diurnal variations, that eye pressures are far from static (this is even more the case with glaucoma). Therefore, the very infrequent exams that patients are receiving, in our opinion, are completely inadequate in describing the behavior of ocular pressure behavior and variation. This is especially true considering the 'off hours' that doctors don't test the very important night time and morning pressures, and the very important charting of diurnal variation of which Dr. Ritch and others have noted as being a predictor of glaucoma risk (the greater the diurnal variation, the greater the risk factor).

Therefore, for one with glaucoma or OHT, the decision to begin the process of self tonometry can be one of the most important, challenging, and rewarding decisions that a person can make. If a person is still undecided whether self tonometry is a worthwhile decision for them, a review of the Fiteyes home page article Why you should Monitor you IOP is highly suggested because it delves into many of these questions, and expounds on some of the pitfalls, objections and concerns which either a doctor or patient may have with the practice of home monitoring of pressures.

ICare Rebound Tonometer as a Home Intraocular Pressure Monitoring Device?

Submitted by Bailey on Mon, 03/07/2011 - 9:47am

I am posting a question (and followup) which we received regarding the following article from the 'Asrani' study on the ICare portable tonometer..

Evaluation of the ICare Rebound Tonometer as a Home Intraocular Pressure Monitoring Device


Are handheld or portable tonometers appropriate for home eye pressure monitoring?

Submitted by dave on Thu, 04/22/2010 - 12:29pm

In any tonometer (based on today's technology), you can have some, but not all of, the following:

  • ease of use
  • accuracy (reliability and validity of data)
  • low cost
  • portability

handheld portable tonometerPeople tend to give a priority to portability and low cost. New products aimed at this feature set have recently been announced. Does it make sense to utilize those devices for self-tonometry?

We have to agree that any trade off that doesn't include reliability and validity of IOP data invalidates the whole endeavor of self-tonometry. Not only is it meaningless to do it if the data is not of sufficient quality upon which to make important decisions, but it could actually be detrimental to do self-tonometry in that case.

With today's technologies, portability entails user-alignment (in the context of self-tonometry). Proper user-alignment to produce a valid measurement, by definition, depends upon user skill as well as various specific conditions of each measurement. User-alignment, regardless of the tonometer, is difficult! (User-alignment is defined as the operator of the tonometer having to align the tonometer with the eye manually. Alignment is a very precise process requiring a steady hand, good eyesight, training and practice.)

Therefore, the requirement of user-alignment conflicts with the requirement of reliability and validity of IOP data. We cannot guarantee reliability and validity of IOP data when variable user skills are required to produce that data.

If any decent ophthalmologist or scientist (or intelligent thinker) considers a set of IOP data, they must consider how the data was obtained. If patient skill played a critical role in producing that data, as it does when user-alignment is required, the clear thinking person will immediately discount that data. Therefore, the self-tonometrist's efforts may not produce much of value.

Preview of the Icare ONE handheld tonometer for home eye pressure monitoring

Submitted by dave on Fri, 04/09/2010 - 11:44am

My evaluation Icare ONE tonometer arrived today. I will compare it to:

    * Icare TA01i
    * Reichert 7CR Tonometer
    * Pascal Dynamic Contour Tonometer
    * Ocular Response Analyzer
    * Reichert AT555 Tonometer
    * maybe another one or two tonometers...

Look for a full review in the near future on FitEyes.com. UPDATE: I have decided not to publish my review of the Icare ONE at this time. Please read Are handheld or portable tonometers appropriate for home eye pressure monitoring?

Let me offer an analogy. If I were reviewing golf clubs, I would not include a review of a baseball bat. A baseball bat is not appropriate for playing golf. During the process of evaluating the Icare ONE, I came to a broader conclusion about all handheld tonometer and their appropriateness for self-tonometry (home eye pressure monitoring). Therefore, I feel it is better to have that general discussion first. You can read my thoughts here: Are handheld or portable tonometers appropriate for home eye pressure monitoring?

There is a related discussion on the Icare ONE here: New iCare ONE Tonometer Designed for Home Eye Pressure Monitoring

For now, here are some pictures of my evaluation Icare ONE tonometer.

Just arriving via FedEx (below). Some tonometers it will be evaluated against are shown in the background.

Icare ONE home eye pressure monitoring tonometer


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