Intraocular pressure is the pressure inside of the eye. According to the American Academy of Ophthalmology, “normal eye pressure has historically been considered a measurement of less than 21 mm Hg”. Mm Hg is the unit of measurement used to measure eye pressure – it refers to millimeters of mercury. Intraocular pressure normally stays below 21 mm Hg, but higher pressure is possible and should be monitored to ensure that it is not damaging to the eye.

Normal intraocular pressure

While normal intraocular pressure is less than 21 mm Hg, every person is different and your normal eye pressure can vary significantly from someone else’s normal eye pressure. The intraocular pressure normal range is between 10 mm Hg and 21 mm Hg. When intraocular pressure strays higher than this range, the eye is at a greater risk for developing glaucoma.

The American Academy of Ophthalmology describes intraocular pressure as follows: “a clear fluid called aqueous humor circulates inside the front portion of your eye. To maintain a constant healthy eye pressure, your eye continually produces a small amount of aqueous humor while an equal amount of this fluid flows out of your eye”. Increased intraocular pressure occurs when the eye is producing more of this fluid than is flowing out of the eye. This creates health risks.

Increased intraocular pressure

Increased intraocular pressure puts one at risk for several eye conditions. According to the American Academy of Ophthalmology, ocular hypertension is the state of intraocular pressure being higher than normal. While this is different than glaucoma, having ocular hypertension puts you at a higher risk for developing glaucoma.

The AAO provides the following factors that may increase one’s likelihood of developing ocular hypertension:

  • People with a family history of ocular hypertension or glaucoma
  • People with diabetes
  • People over age 40
  • People of African-American descent
  • People who are very myopic (nearsighted)

Because ocular hypertension does not have any noticeable symptoms, it is important to have regular appointments with your eye care professional.


Intraocular Pressure

Increased intraocular pressure can also be a factor in glaucoma. The Glaucoma Research Foundation explains that “A person with elevated IOP is referred to as a glaucoma suspect, because of the concern that the elevated eye pressure might lead to glaucoma. The term glaucoma suspect is also used to describe those who have other findings that could potentially, now or in the future, indicate glaucoma”. The foundation goes on to explain that vision loss from glaucoma occurs when the eye’s pressure becomes so high that it damages the optic nerve. When detected early, high intraocular pressure and glaucoma can often be treated and maintained so that the eye does not sustain lasting damage.

Intraocular pressure testing is part of a standard eye exam performed during an appointment with your eye care professional. Frequent eye exams allow for early detection of glaucoma, ocular hypertension, and countless other eye conditions.