"You're not going to do that one where you blow air in my eye, are you?!"
This is a phrase us Optometrists have been hearing for decades (since 1986 to be exact). But, what is the 'puff test', why is it done, and do you really need it?
With a puff of air being fired in to your eye, it's easy to understand why you and countless others would rather skip this test. For decades, it has probably been the most annoying, dreaded part of your eye exam.
What is the air-puff test?
Traditionally, optometrists measured the pressure within your eye using the air-puff test. This is a form of tonometry - a test for measuring how much fluid pressure is inside your eyes (also known as intraocular pressure - IOP). Similar to how your body has a blood pressure, your eye has a separate (unrelated) pressure.
While eye pressure is not linked to blood pressure, the two are similar in the way they are monitored.
More specifically, the puff-test is a form of non-contact tonometry, meaning it allows optometrists to measure intraocular pressure without touching the eye. The machine used to measure eye pressure is called a tonometer.
How does it work?
An air-puff tonometer expels a small puff of air on to the front surface of your eye (cornea). Once the air is released, the tonometer calculates the intraocular pressure based on the time it takes for the air to bounce back to the machine.
Although this might be a little uncomfortable, it’s not painful; nothing but the puff of air touches your eye.
Normal IOPs range from 10-24mmHg (millimetres of mercury).
Do I need it?
Monitoring IOP is important to rule out risk of eye diseases developing. Elevated IOP is sometimes referred to as ocular hypertension, which can put you at risk of developing glaucoma. Glaucoma is symptomless in its early stages and can cause sight loss, but is easily treated (simply using eye drops) if caught early.
If you're over 40, or at risk of developing glaucoma, it’s critical for your optometrist to perform tonometry as part of a comprehensive eye exam. Which is why it's important for you to have eye examinations regularly, even if you aren’t experiencing symptoms.
Are there other methods?
Yes! Some optician practices have moved on from this traditional technique, and are instead using more innovative (and comfortable) methods to measure IOP.
Contact tonometry is often used in a hospital setting as it is the "gold standard" for measuring IOP. This method requires a small (generally plastic) probe to applanate the front surface of the eye, requiring topical anaesthetic.
In optometry practice, the iCare tonometer is a great alternative as it doesn't require anasthetic. It's arguably more accurate than the "puff test" and is generally a more comfortable experience.
So, why are optometrists still doing it?
Many optician practices may be of the belief 'If it ain't broke, don't fix it'. After all, it's a quick, cost-effective way of measuring your eye pressure. The air puff costs approximately 7p per use, compared to £1.12 for newer methods.
If you don't want the air puff test, ask your optometrist about the alternatives that they offer.
At CBTR Opticians, we've invested in hospital-grade technology to ensure our clients have an enjoyable experience. And, yes, that means no more air-puff test! Modern innovation allows for more comfortable (and precise!) testing methods.