You are here

Home » Community » Blogs

How To Measure Your Eye Pressure At Home And Change the World Too!

Submitted by dave on Wed, 04/15/2009 - 9:53pm

There are certainly a lot of glaucoma patients who could benefit from home eye pressure monitoring. I'm one of them. However, there are probably also some glaucoma patients for whom home eye pressure monitoring is not a good idea. Check with your doctor and don't make any decisions about purchasing expensive equipment while under emotional stress (such as immediately after a glaucoma diagnosis).

By continuing to read this article, you agree with my disclaimer and the terms of use of this site. Specifically, I recommend that you consult your physician or local treatment center before pursuing anything you read about on this site.

In response to something I posted on a forum, a reader asked me, "How do you check your own pressure?  Can one buy a device for doing this?"

This question comes up a lot. I'm going to attempt to give my best response in this post. First, however, I must say that I feel anyone interested in this subject should understand the issues raised by an ophthalmologist who told me that all my efforts measuring my eye pressure are a waste. I'm linking to that past blog post not because I think it is a waste to monitor your eye pressure at home, but because I think anyone with glaucoma needs to be very well-informed on these issues. If you don't feel well-informed on all these issues, and if you don't have the support of your physician, I can't recommend that you act on any of the information in this article.

With all that out of the way, I'd like to share my thoughts and experiences with you. I believe that monitoring my eye pressure closely has been invaluable for me. I also monitor a lot of other things, but intraocular pressure is still considered the most important risk factor in glaucoma. And I believe intraocular pressure is misunderstood. Therefore, we, the community of glaucoma patients, have two important opportunities in regard to monitoring our intraocular pressure right now.

howtochangetheworld Therefore, anyone who can already monitor their eye pressure at home with a professional quality tonometer, please consider joining our intraocular pressure research project. By joining, you will receive many benefits that I think will advance your own understanding of the positive things you can do to manage your eye pressure; you will also be doing something of great value for the community of glaucoma patients and the scientists working on treatments.

I can imagine that in the future glaucoma patients will monitor their eye pressure the way diabetics monitor their blood sugar today. I think most physicians treating diabetes would not dream of caring for a patient without knowing details of how that patient's blood sugar responds to his or her diet and activities throughout the normal course of the patient's life. I believe the same should be done for glaucoma patients.

For at least some glaucoma patients, intraocular pressure can fluctuate widely in response to common activities and stress encountered in everyday life. My intraocular pressure can double or halve as a result of simple things that happen during my day. The single eye pressure measurement every few months in my doctor's office proved inadequate and misleading in my case.

I suspect that many other glaucoma patients who continue to lose vision or experience deterioration of the optic nerve might derive great benefit from either monitoring their condition closely like I'm doing or even by just following up with their physician based on ideas that come out of the experiences I'm sharing. It would be so much better if others share their story or their data through this web site. If you want to share, I will help you get started. If you can collect eye pressure data, please contact me.

If you are interested in monitoring your intraocular pressure at home and you haven't done it before, I'll tell you what I have learned.

  • Don't rely on the Proview home tonometer. It costs about $75 on eBay, which makes it the only truly affordable tonometer I know of. However, for many people the eye pressure values it reports have absolutely no relationship to true intraocular pressure. Our research project has the world's most accurate tonometers (Pascal Dynamic Contour tonometer, Reichert Ocular Reponse Anaylzer, Goldmann Applanation tonometer) and I have compared the Proview against these other tonometers many times. In fact, I have worked extensively to find ways to make the Proview provide more useful results. My conclusion is that the concept upon which the Proview is based is flawed and that the Proview cannot provide accurate eye pressure results for a large percentage of people. It seems to work reasonably well for a small percentage of people, but even for those people the results are not research quality. The published research on the accuracy of the Proview is in agreement with my position.
  • (AT555 and AT550 are no longer recommended by FitEyes- replaced by R7 and 7CR -2013) I recommend a Reichert AT555 non-contact tonometer as a very good solution. It is extremely easy to use. In fact, you can take your own eye pressure measurements very easily. I have found the AT550 and AT555 models to be very accurate. Here is another discussion about the best tonometers.
  • The Tiolat iCare rebound tonometer is another good option for some people. See our forum discussion on the iCare here.
  • UPDATE - the TonoPen is not a choice for self-tonometry. If you work closely with your doctor, you could consider a Tono-Pen XL tonometer. A used Tono-Pen can be purchased for less than $3000. However, they are not as safe as the non-contact tonometers or nearly as easy to use. And my personal opinion is that they are no more accurate. In fact, the research shows that the Reichert AT555 is more accurate than the TonoPen. The non-contact tonometer has the advantage of allowing you to collect a lot more measurements and more data can lead to better conclusions. For my purposes, I believe a high-quality non-contact tonometer can often be a better choice. The TonoPen has the advantage of being very portable as well as less expensive. If you choose this option, you will need to acquire significant skill to use the TonoPen properly and you will need to discuss with your doctor a strategy for anesthesia. If you must use anesthesia (the TonoPen does contact the cornea), this will limit the number of eye pressure measurements you can acquire during any given period of time because over-use of anesthesia is unhealthy for the cornea.
  • UPDATE - the Keeler Pulsair EasyEye (the latest model) is not suitable for self-tonometry. Previosly, I had said, "Another good choice might be the Keeler Pulsair tonometer. It is possible to learn to use it for self-tonometry. (UPDATE: click this link to download the full article in PDF format.) The Pulsair is accurate and has been evaluated in many peer review studies. If your doctor will help you learn to use it, this could be a very good option." That statement does not apply to the newer Pulsair models. They cannot be used for self-tonometry. Therefore, the statements below are also inaccurate in regards to self-tonometry:
    • If you have normal tension glaucoma or suspect postural changes my affect your eye pressure, the Pulsair has an advantage over the Reichert AT555 in that it can be used in a variety of positions, including supine.
    • The Pulsair is somewhat portable and the AT555 is not.
    • I believe the Pulsair can be purchased for about $4995, giving it another advantage.
    • The Pulsair is not nearly as easy to use as the AT555. In the study that taught people to do self-tonometry (download PDF), only about 75% of the patients could do it correctly, after extensive training. My guess is that a much larger percentage would be able to do self-tonometry with the AT555. In fact, I think almost anyone with a decent amount of vision can perform self-tonometry with the AT555. The AT555 is much easier to use than any other tonometer I have seen.
  •  UPDATE - the PT100 is not a choice for self-tonometry. Another good choice might be the Reichert PT100. This is a portable tonometer like the Keeler Pulsair.
    • It is more expensive than the Keeler Pulsair by about $1000, depending on where you purchase it.
    • It appears to be much more difficult to use for self-tonometer. I'm not even sure it is possible to reliably use it for self-tonometry at all.
    • If you have a friend or family member who will be measuring your eye pressure, the PT100 might be an option, but it is many times more difficult to use than the AT555 and it is also slightly more difficult to use than the Keeler Pulsair in my opinion.
    • The PT100 is smaller, lighter and more portable than the Keeler. It is cordless.
    • Optometrist Ainsley Smith reviews the Reichert PT100 tonometer in this article (PDF).
    • In our forum we discussed the PT100 and the Keeler Pulsair tonometers recently.
  • The Canon TXF non-contact tonometer is another option, but I can't think of any reason to choose it over the Reichert AT555. It is also slightly more expensive and it is not as easy to use for self-tonometry.
  • The Nidek NT-4000 is an interesting choice (because it has pulse-synchronization), but the same caveats apply: it is  more expensive and it is not as easy to use for self-tonometry as the Reichert AT555.
  • If you want to test the waters before spending thousands of dollars, you can look for used tonometers. I have a whole list of contacts I may publish in the future. For now I will mention a couple options:
    • You can find Reichert NCT II (model 12415) non-contact tonometers on eBay for $200 to $250 plus about $25 shipping.
      • If the person shipping the tonometer to you does not pack it very carefully, the safety stop will break and using the tonometer will be dangerous!
      • These tonometers are about 20 years old. They will not be very accurate. However, even though the reading may be off by as much as 5 mm Hg, for example, the instruments can still give consistent readings. Therefore, if you only want to find out if your eye pressure does fluctuate in response to events in your life, you can probably answer that question with one of these instruments.
      • You may be lucky enough to find an old Reichert NCT II in good condition and with a small error. However, you may have to purchase more than one before you find a good one. And if you aren't working closely with your doctor, you won't know if you have a good one.
      • Reichert cannot recalibrate these tonometers any longer. They cannot be factory serviced or repaired.
      • You cannot use them for self-tonometry. And the person taking the measurements needs to be trained. They are not easy to use.
      • Even with all those caveats, this is a far better option than the Proview if you want to limit your costs while seeing if there is any promise in home eye pressure monitoring for you.
      • If you purchase an old Reichert NCT II (model 12415) I have instructions on how to use them. I will only provide this information if doing so doesn't violate any regulations. I may require you to agree to a waiver also.
    • Used Reichert Xpert Plus tonometers are available and they can be a good choice. This is a much newer model than the Reichert NCT II. Many doctors currently use the Xpert Plus and are happy with it. One of my doctors has an Xpert Plus (in addition to a Goldman applanation tonometer) and we make use of it frequently. The eye pressure values are about the same as the AT555. However, you will have to have someone else take your eye pressure with this tonometer. You cannot use it for self-tonometry.
  • The Diaton tonometers are not very accurate and they are not very easy to use correctly. Marcel owns one of these and he has found that it is not suitable for self-tonometry at all. I have not used one yet, but I would be interested in hearing from others who have used them for self-tonometry. If you have a different opinion on the accuracy (and you are not a Diaton sales person), I'd like to hear from you. BTW, these are the tonometers that are being aggressively marketed everywhere on the Internet. They sell new for $2000 and up with the most common price being $2500. The marketing claims that this is an accurate tonometer are not backed up by the research. In fact, the manufacturer's best claimed accuracy in the hands of a highly-trained user (a doctor who uses it daily) is +/- 2 mm Hg up to 20 mm Hg and then 10% error up to 60 mm Hg. Those are large errors!
  • Be aware that different brands and types of tonometers give different measurements. If a lot of people start doing this, it would be great if we have some consistency in methods and instruments.

For most people, the Reichert AT555 (now 7CR) will be the easiest tonometer to use accurately. There is almost no way you can go wrong. If you use a Reichert AT555 non-contact tonometer, about the only advice you need to know is that it is important to keep your chin fairly close to the instrument. If the instrument is too low and you have to bend forward and down, you may be too far away. I recommend that you set the height so that you have good natural posture while checking your eye pressure.

To use the Reichert AT555 (now 7CR) non-contact tonometer, you simply sit on the patient side, look at the light, and push the button. That's all there is to it. (It comes with full instructions.)

We have a private forum here on for the discussion of how to perform self-tonometry research. If you have a professional quality tonometer and want to participate in our research, please contact me and I will give you access to this forum. However, the information below is a general overview. 

I would highly recommend that you set the instrument up to take three measurements with each eye. I call this collection of 6 total measurements an "Eye Pressure Exam".  Sometimes I collect more than 6 measurements in an eye pressure exam. I never throw out any measurements. The tonometer will sometimes indicate if it thinks a measurement is not valid. It can detect several different conditions that indicate another measurement is required. I perform an additional measurement when required, but I also note and record every value. That's just the way I do it.

I also pay attention to the order in which I take the measurements. You could take 3 measurements with one eye, and then switch to the other eye. You could alternate the eye you start with. Or you could alternate eyes with each measurement.

The Reichert AT555 (now 7CR) non-contact tonometer will print out the results for you. It will also send the measurements directly to a computer over a serial cable connection. I would encourage anyone monitoring their eye pressure to consider keeping good records (and even sharing the data with our research project as I mentioned above). We can perform detailed data analysis on intraocular pressure data and I am sure you and your physician will find our analyses beneficial.

I would encourage anyone monitoring their eye pressure at home to check it upon awakening in the morning. Be aware that your eye pressure may change quickly, so a few minutes of time can impact whether the eye pressure measurement truly reflects your eye pressure upon awakening vs. your eye pressure while moving around.

If you use a Reichert AT555 (now 7CR) non-contact tonometer, it is so quick and easy to check your eye pressure that you can do it any time you suspect your eye pressure may be elevated.

I would encourage you to work closely with your doctor at every step of the way. I hope you are lucky enough to have a doctor who is helpful. I know several people who don't have such good fortune and that's a tough situation.

I have several really good doctors I work with and I appreciate everything they have done to help me along in my eye pressure research project. I'll try to help anyone else who wants to contribute eye pressure data to our research project.

Subscribe to RSS Feed