Intraocular pressure (IOP) is the pressure in your eyes. When that pressure is higher than normal, it causes ocular hypertension. While ocular hypertension isn’t an eye disease in itself, it is an indication that you could develop glaucoma.
Your eye pressure is measured in millimeters of mercury, expressed as mm Hg. Normal eye pressure is between 10 to 21 mm Hg. High intraocular pressure is greater than 21 mm Hg.
What causes ocular hypertension?
There are five main causes of high eye pressure that can lead to an ocular hypertension diagnosis.
Overproduction of aqueous: Aqueous humor is a clear, watery fluid in the eye behind the iris. Its purpose is to bathe and carry oxygen and nutrients to the lens, and help maintain pressure. It flows through the pupil and fills the space between the iris and the cornea, then drains through a structure called the trabecular meshwork.
Sometimes the body produces too much aqueous. If aqueous is produced at a higher rate than it can drain, that causes increased eye pressure.
Slow aqueous drainage: If for any reason the drainage system doesn’t function as it should, the aqueous accumulates and drains too slowly. Even if the body is producing the right amount of the fluid, inadequate drainage can also cause ocular hypertension.
Trauma to the eye: This also has to do with aqueous. Some injuries disrupt or affect the balance of aqueous production and drainage, which can lead to high eye pressure. Note that a trauma can affect your eyes months or years after the actual injury takes place, so let your eye doctor know if you’ve had an injury in the past.
Medications: Steroid medications, including steroidal eye drops, could cause high eye pressure.
Other eye conditions: Conditions including corneal arcus, pigment dispersion syndrome, and pseudoexfoliation syndrome are all associated with ocular hypertension.
Who gets it?
Risk factors include being older than 40: in the United States, it’s estimated that as many as 10% of adults older than 40 have intraocular pressures of 21 mm Hg or higher.
Race and family history can also increase your risk of high eye pressure and glaucoma, as well as those with thin central corneas or who are very nearsighted.
How is it detected?
Ocular hypertension typically doesn’t have any side effects or symptoms. At your annual eye exam, your eye doctor will use an instrument called a tonometer to measure your IOP. He or she will also check for other eye diseases, including for signs of glaucoma by looking for optic nerve damage and examining your peripheral vision.
When is high eye pressure serious?
It does make you at higher risk for developing glaucoma, so having ocular hypertension would make you a “glaucoma suspect.” Because glaucoma is a disease that damages your optic nerve and ultimately could cause vision loss, your eye doctor would want to closely monitor your eye pressure and advise steps to diminish it.
Glaucoma can cause symptoms like severe and throbbing eye pain, headache, blurry vision, nausea and vomiting, eye redness, or seeing halos. Be sure to check with your doctor immediately if you experience any of these symptoms.
How can eye pressure be reduced?
Your eye doctor may prescribe special eye drops to reduce eye pressure. You can also control high eye pressure and improve your overall eye health through good lifestyle choices:
- Eat a healthy diet that includes lots of fruits and vegetables.
- Get regular exercise.
- Stay hydrated.
- Limit caffeine consumption.
Getting regular eye exams is sometimes the only way to detect certain eye conditions. Contact us to schedule your exam or ask questions about your eye care today.