Practicing good eye care is crucial to preserving your vision. To do so, you must understand key terms, such as intraocular pressure (IOP). IOP is the fluid pressure inside of your eye and is an important measurement taken during every eye exam. If your IOP is uncontrolled, it may lead to glaucoma. Learn more about normal eye pressure means, how your IOP is measured, and what can happen if your IOP is too high* 

What is normal eye pressure?

When your IOP is measured, what’s really being measured is the fluid in your eye. This fluid, called aqueous humor (AH), drains out of the eye and is replaced by new fluid. Under normal conditions, your body can create a homeostatic balance and regulate IOP all on its own. 

Normal eye pressure can vary by person—anywhere from 12-22 mm HG, according to the Glaucoma Research Foundation (GRF). This is why it’s important to schedule regular eye exams and learn what your “normal” is. Through regular check-ups, your eye care professional can evaluate trends and recognize a worsening IOP.

A high IOP, also known as ocular hypertension, is an “eye pressure of greater than 22 mm Hg,” states the GRF. High eye pressure is typically of greater concern than low eye pressure, as it can eventually lead to glaucoma and vision loss if left untreated. 

How is eye pressure measured?

Eye pressure can be measured at your eye doctor, your primary care doctor, or in the emergency room (ER). Depending on the setting, there are different tonometry tests to measure IOP including: 

• Goldmann applanation is the most commonly used and considered by some to be the gold standard of measuring IOP. This test uses a flat-tipped probe that is gently pressed against the surface of your eye.
• The Tono-Pen and iCare tonometers both work by using air pressure applied to the eye using an instrument that slightly flattens the cornea. 
• The newest tonometry instrument, the Diaton tonometer, is ideal for patients unable to open their eyes and/or previously had surgery on their eyes. This pen-like instrument has a stainless steel tip that can get an IOP reading through the sclera and eyelid, i.e. without having to make contact with the eyeball or the cornea.

Why is having normal eye pressure important?

Over time, a high IOP can cause the fibers in the retina to die, which can result in vision loss and glaucoma. If glaucoma is left untreated, significant vision loss and blindness are common. Sadly, there is currently no way to prevent or reverse glaucoma, but there are eye medications that can slow the progression of the disease.

What treatments are available for IOP and glaucoma?

There are both pharmacologic and non-pharmacologic treatment options. Before starting any treatment options, it is important to discuss all your current medicines, vitamins, and supplements with your doctor. 

For many doctors, the first strategy to improve IOP is eye drops. The most common eye drop medications are: 

• Beta-blockers (betaxolol)
• Topical carbonic anhydrase inhibitors (dorzolamide, brinzolamide)
• α2 adrenoceptor agonist (Brimonidine)
• Cholinergic agonists (pilocarpine)
• Prostaglandins (latanoprost, unoprostone isopropyl, travoprost)
• Prostamide (bimatoprost)
• Combination medication drops (Cosopt, Combigan, Simbrinza)

If eye drops are not effective, the next option is oral medications that work by decreasing the amount of AH in the eye. Eye surgery is another option that is common among glaucoma patients if other treatments, like eye drops, don’t work or cease to be effective.

Non-pharmacologic therapies are not approved by the Food and Drug Administration (FDA) and aren’t used to directly treat IOP. Some people use them, however, as a complementary treatment. 

These complementary therapies include:

• Homeopathic remedies
• Diet changes, including decreasing caffeine intake
• Physical exercise
• Bilberry extract supplements
• Herbal supplements
• Osteopathy
• Vitamin C supplements
• Physiotherapy
• Elevating the head of the bed while sleeping

Before trying any complementary treatments, consult with your healthcare provider first.

*Gaines, K. (2021, Jan. 11). Normal Eye Pressure: Tests and Treatment. Verywell Health. https://www.verywellhealth.com/normal-eye-pressure-5094999

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