If you have ever been to the eye doctor, you have likely experienced the “air puff” eye test. This test is a way to check the pressure in the eyes. The eye pressure is a key measurement for glaucoma which is a serious eye disease. While the air puff may be annoying or slightly uncomfortable, it is an important screening measure to reduce the risk of severe glaucoma.
What is Eye Pressure?
Like blood pressure, the eye pressure is a measure of how much fluid is in the eye and exerting a force on the eye.
While eye pressure is not linked to blood pressure, the two are similar in how they are monitored.
In the front of the eye, there is a space filled with fluid called aqueous. If there is too much fluid at one time, it will cause the eye pressure to be too high.
Conversely, if there is not enough fluid, the eye pressure will be too low.
The normal range for eye pressure is between 10 and 20 mmHg.
How the Air Puff Works
The air puff test is also called a non-contact tonometer (NCT). This instrument measures the pressure inside the eye by applying a puff of air with a known force to the eye and measuring the resistance.
If the eye pressure is higher, there will be more resistance to the air puff and the instrument can measure this resistance and convert it into a number for the pressure of the eye.
Since the air puff test relies on the resistance of the eye, the eye must be open and cannot blink during the measurement or the results will be off.
Risks with High Eye Pressure
If the eye pressure is too high or above the normal range, there is an increased risk of glaucoma.
Glaucoma is a chronic eye condition that results from the pressure in the eyes being too high and damaging the optic nerve in the back of the eye.
Another risk if the eye pressure is too high is corneal angle closure. This means that the fluid in the front of the eye cannot drain at all and will result in eye pressure spiking very high and causing pain, nausea, and loss of vision.
Early Treatment for Glaucoma
Since glaucoma is a chronic, progressive eye condition, it is important to receive treatment early on in the course of the disease.
In the early stages of glaucoma, there may not be any signs or symptoms of damage and if progression is prevented, the entire eye and vision can be spared.
However, in later stages, glaucoma can result in loss of vision and visual field defects which are not repairable.
To prevent these worse outcomes, it is valuable to screen for glaucoma using the air puff test every year when you have a comprehensive eye exam.
Alternatives to the Air Puff Test
In most offices, the air puff test is the standard method for measuring the eye pressure. However, there are a few alternatives including contact tonometry and the iCare tonometer.
If you have issues with the air puff test, ask your eye doctor about the alternatives that they offer.