For many patients, the strangest part of an eye exam is when the eye doctor shoots a puff of air into their eyes. It doesn't hurt, but it is a weird feeling, and it always surprises you. If everything is okay, your eye doctor will just say something like "looks good," and then you'll be on to the next part of the exam. Perhaps this is why so many patients are left wondering what the air puff test really does and why it's so important. Those questions will be answered in this article.

What is the air puff test, and what does it assess?

The air puff test is more formally known as non-contact tonometry. Its purpose is to basically test how your eye responds to air pressure, which indicates the pressure inside the eye — or the intraocular pressure. The instrument used to conduct the air puff test measures how much the surface of your eye indents in response to the puff of air. The less it indents, the higher the pressure inside your eye.

Why is the air puff test important?

The air puff test is important because elevated intraocular pressure often indicates a condition called glaucoma. Since glaucoma does not cause any symptoms in its early stages, patients often don't find out they have it until they visit the eye doctor. And diagnosing glaucoma before symptoms appear is really important since the first symptom is usually vision loss that you can't recover. If glaucoma is detected early, then your eye doctor can prescribe medications that will hopefully keep you from losing any vision.

What happens if your eye doctor gets a worrisome result from the air puff test?

If the air puff test does indicate that your intraocular pressure is high, then your eye doctor will not automatically diagnose you with glaucoma. But they will schedule you for a more involved set of tests, such as a dilated eye exam. This will basically allow them to see inside of your eye and assess whether there has been any damage to your ocular nerve as a result of your elevated eye pressure. This test will tell them whether you have glaucoma.

The next time your eye doctor gives you an air puff test, you'll have a better understanding of what's going on and why this test is important. If you have any additional questions, don't hesitate to ask your eye doctor.