When we go to the eye doctor, many of us, including myself, are scared of the machine that blows air in our eyes. Why is the puff of air so intimidating? I know the puff of air is coming, it’s a scary/anxious feeling, I have to make sure my eyes stay open or it’s going to be embarrassing, but somehow I still blinked. The nerves in the cornea give a signal to the brainstem in order to protect the eye, therefore the phenomenon of corneal reflex occurs. It’s where the eyelids close before you can even stop it. Then you question why am I here, do I even need my eyes checked, what is this stupid test? This stupid test is actually very important. It’s called tonometry and it measures intraocular pressure. Aqueous humor is the clear fluid that the front of the eye is filled with and is constantly making. The purpose of the aqueous humor is to drain out and if the drainage doesn’t happen then the pressure builds up. Results of this include damaging the optic nerve or more importantly the peripheral vision first. This is the leading cause of irreversible blindness worldwide known as glaucoma. People with diabetes may be at a higher risk and some medications, especially individuals who take steroids therefore, it’s essential for physicians to check eye pressures during an annual exam.
A quick burst of air comes from the air puff tonometry to briefly flatten the cornea and the sensor within measures how much force it took. Typical normal ranges are between 10-21 mmHg, but can vary from person to person. The interesting part is that nothing actually touches your eyes. Luckily, the clinic I used to work at didn’t have this device and chose a friendlier one. The iCare tonometry utilizes a very small plastic ball to the cornea and back. It’s very similar to the traditional tonometry, however the iCare tonometry measures how quickly it rebounds. Now, I understand it sounds a little intimidating with something touching the eye, but it’s super fast and painless, and many of my previous patients had mentioned how it tickles their eyelashes (if that’s even possible). So next time, be brave because a few seconds of discomfort protects vision you can’t get back.
References:
Cleveland Clinic. (2022, May 25). Tonometry: What Is It, Test Procedure, Ranges & Results. Cleveland Clinic. https://my.clevelandclinic.org/health/diagnostics/22859-tonometry
Icons8. (n.d.). tonometry. Icons8. Retrieved September 27, 2026, from https://icons8.com/icon/rrpp0hc9hrAx/tonometry
World Health Organization. (2023, August 10). Blindness and vision impairment. World Health Organization. https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment
I find it interesting how many people will avoid the eye doctors,I know form experience that I have lot of people i know especially close family and friends that have a bad stigma of eye doctors just because of the puff machine. I am glad I can let them know the importance of this test and to follow up annually!
ReplyDeleteI find it quite fascinating that the technology clinics and physicians can use to test their patients is always so creative; it's also so simple and efficient, but also very complex to make and use. Do you know if there is a stark difference between the tonometry and the iCare tonometry besides the use of a plastic probe that quickly gets launched out? Or if one machine is preferred over the other?
ReplyDeleteGreat post! I remember dreading tonometry when I was younger too! I'm pretty sure that involuntary blink is a protective reflex arc: sensory signals travel via the trigeminal nerve (CN V1) to the brainstem, triggering the facial nerve (CN VII) to contract the orbicularis oculi muscle. Routine tonometry embodies beneficence by detecting silent intraocular pressure spikes before optic nerve damage occurs. Meanwhile, using gentler tools like iCare aligns with nonmalfeasance by minimizing patient distress. From your clinic experience, did explaining how the test works help ease patients' anxiety?
ReplyDeleteI love this post (obviously)! I would change this definition of glacuoma though as POAG (primary open angle glaucoma) can have similar symptoms as described with an increase of pressure that causes damage to the optic nerve, but what about Normal Tension Glaucoma? A reading on and iCare or through applination would have a normal pressure but vision loss would still remain. The pressure is not what causes the damage to the optic nerve is all cases but it is still a great screening tool esspecially as it is very accessible and easy to do (takes 5 seconds for both eyes).
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