Many people put off regular eye care until there’s a major problem that interferes with their daily lives. Here, optometrist Melanie J. Denton, O.D., MBA, FAAO explains why you shouldn’t wait, and answers common questions she hears from patients regarding overall eye health, and specifically eye pressure: what it is, how it’s tested, and why it’s so important.*

What is intraocular pressure? 

The human eye can be compared to a beach ball. To keep it inflated and its structures intact, there needs to be pressure inside, pressing outward. Instead of air pressure, the eye makes fluid to keep its globe-like shape. This fluid is constantly regulated to maintain a healthy internal eye, or intraocular, pressure (IOP). High IOP is a risk factor for glaucoma.

Is glaucoma tested in every eye exam? 

In comprehensive eye exams involving eye pressure testing, the answer is “yes.”

How is eye pressure tested? 

Eye pressure is tested by applying a gentle force to the front surface of the eye and measuring the amount of force the eye generates in response. Testing can be done in several ways:

• An air puff test (widely known and involving no direct eye contact)
• A measuring probe, such as the handheld iCare tonometer and Tono-Pen devices
• A blue light test (Goldmann tonometer)

The air puff test can be “a little terrifying” for some patients, but Denton says it’s effective for measuring IOP.

What can patients expect during probe testing? 

Prior to testing, numbing drops are used in the eyes. The numbing effect lasts about 20 minutes, during which the eyes will feel ”a little weird.” There is no pain at all, though, and the procedure is over “very, very quickly.”

What is normal eye pressure? 

Normal eye pressure ranges from 10-21 mm Hg (millimeters of mercury) and depends on the individual. Normal for one person could be high for another. For some people, higher eye pressure doesn’t cause any issues. Denton urges listeners to speak to their doctor about their eye pressure, to determine what’s normal for them.

Why is eye pressure so important? 

High eye pressure is the most common risk factor for glaucoma, so regular monitoring is necessary. For those who already have glaucoma, regular monitoring is important to ensure that the treatment for lowering internal eye pressure is effective. You don’t want inner eye pressure to get too low, however, as that can lead to other eye health and vision issues. 

Denton advises listeners to have their eye pressure checked yearly. “If you haven’t had an eye exam in a while, I definitely recommend that you do it,” she says, “and you’ll know more about why they’re testing your eye pressure this time.”

*Eye School with Dr. D. (2019, December 11). What You Need to Know About Eye Pressure | All About Intraocular Pressure in Your Eye [Video file]. Retrieved from https://www.youtube.com/watch?v=medcwQ7MxpM