Intraocular (say "in-truh-AW-kyuh-ler") pressure is the pressure caused by the
fluid inside the eye that helps maintain the shape of the eye. The level of
pressure inside the eyes depends on:
How much fluid is produced inside the
Whether fluid can travel normally through the
How well the fluid drains from the eye.
The pressure within the eyes varies during the day. Normally,
the pressure inside the eye ranges from 10 millimeters of mercury (mm Hg) to 21
Intraocular pressure (IOP) can vary from person to
person. The higher the pressure in the eye, the greater the chance
of damage to the optic nerve. Optic nerve damage leads to the eye disease glaucoma. Some people who have higher-than-normal
pressure in their eyes don't develop
Not all people with glaucoma have
increased pressure inside the eye.
Many people who have intraocular pressures consistently
above 27 mm Hg develop optic nerve damage unless the pressure is lowered by
Some people have intraocular pressures consistently
higher than 21 mm Hg but do not develop optic nerve damage. This condition is
called ocular hypertension.
Doctors measure IOP with a tonometry test. This is one of several tests that helps determine your risk for glaucoma.
Adam Husney, MD - Family Medicine & Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology