If you have glaucoma, you probably hear a number every time your eye pressure is checked. You may be told that your pressure is 12, 18, 22, or another number measured in millimeters of mercury, or mmHg.

But is that number good or bad? Is it low enough to protect your vision?

The answer depends on your individual eyes. According to the Glaucoma Research Foundation, there is no single eye-pressure level that is safe for everyone. Instead, your doctor may establish a personal goal known as your target eye pressure.*

“Normal” Eye Pressure Is Not the Same as Safe Pressure

Eye pressure, also called intraocular pressure or IOP, is created by fluid inside the eye. Your eye continuously produces and drains this fluid. If it does not drain properly, pressure can build up.

Most people have eye pressure between 10 and 21 mmHg. However, experts increasingly prefer to call this the “average” range rather than the “normal” range.

That is because:

• Some people have pressure above 21 mmHg without optic nerve damage.
• Some people develop glaucoma even when their pressure stays below 21 mmHg.
• A pressure that is safe for one person may be too high for another.

For example, someone may have a pressure of 20 mmHg and show no signs of glaucoma. Another person may continue to experience optic nerve damage at 15 mmHg.

High eye pressure is an important glaucoma risk factor, but the number alone does not tell your doctor whether the disease is controlled. Your optic nerve health and changes in your vision must also be considered.

You usually cannot feel high eye pressure. Most pressure changes cause no pain or obvious symptoms, which is why regular examinations and testing are so important.

Learn how the IOP test is performed: Intraocular Pressure (IOP) measurement with Icare tonometry for the screening of glaucoma. Focal Pointe Eye Care

How Is Your Target Eye Pressure Chosen?

Your target pressure is the level your doctor believes will reduce the risk of additional optic nerve damage and vision loss. It is not a universal number or a guarantee. It is a personalized treatment goal that may change over time.

Your doctor may consider:

• Your pressure before treatment began
• The type and stage of your glaucoma
• How much optic nerve damage is already present
• Whether your visual field or OCT results are changing
• The thickness and stiffness of your cornea
• Your age, health history, and other risk factors
• How quickly your glaucoma appears to be progressing
• The benefits and possible risks of lowering your pressure further

Your cornea—the clear front surface of your eye—can affect how pressure is measured. A thicker cornea may make the reading appear higher, while a thinner cornea may make it appear lower. Your doctor may order a test called pachymetry to measure corneal thickness and interpret your pressure readings more accurately.

According to a BrightFocus Foundation treatment guide, an initial goal for someone with mild optic nerve damage may be to lower pressure by approximately 20% to 25% from their average pretreatment level. Someone with more advanced or quickly progressing glaucoma may need a lower target.

Your doctor may use prescription eye drops, laser treatment, surgery, or a combination of treatments to reach that goal. Always consult your eye doctor before changing or stopping glaucoma treatment.

Your target can change

A target pressure is better viewed as a guide than a permanent line in the sand.

If your OCT scans and visual field tests remain stable, your doctor may decide that the current pressure is providing enough protection. If testing shows continued damage, your target may need to be lowered—even if your pressure falls within the average range.

Your target may also be adjusted if treatment causes significant side effects or other health concerns. The goal is to balance pressure control with the safety and daily burden of treatment.

Does One Good Reading Mean Your Glaucoma Is Controlled?

Not necessarily. Eye pressure can change by the hour, day, and week. It may be affected by the time of day, medication schedule, body position, and other factors.

A pressure measurement during an appointment is only a snapshot. One low reading could mean that treatment is working, but it could also reflect a normal fluctuation.

Your doctor looks for a pattern over time. Signs that glaucoma is under control may include:

• Pressure readings that consistently stay near the target
• Stable visual field test results
• No meaningful changes in OCT imaging
• No new optic nerve damage
• Consistent use of prescribed treatment

This is why you should keep your appointments even when your pressure was “good” at the last visit or your vision feels unchanged. Glaucoma can progress without noticeable symptoms.

If you use glaucoma medication, take it exactly as prescribed. Tell your doctor if you miss doses, experience side effects, have difficulty using the bottle, or cannot afford your medication. These challenges can affect pressure control, and your care team may be able to help.

Questions to Ask Your Eye Doctor

Consider bringing these questions to your next appointment:

• What is my target eye pressure?
• What was my pressure before treatment?
• How did you choose my target?
• Does my corneal thickness affect my readings?
• Are my visual field and OCT results stable?
• Has my target changed since my last appointment?
• What happens if my pressure stays above the target?
• How will we know whether my treatment is working?
• Should my pressure be checked at a different time of day?

Knowing your target can help you understand the purpose of your treatment and participate more confidently in your care.

References

• Glaucoma Research Foundation. (March 21, 2023). “What Eye Pressure Is Safe for Me?” glaucoma.org
• BrightFocus Foundation. (January 9, 2023). “Glaucoma and Eye Pressure.” brightfocus.org

The information provided by The Glaucoma Community is for educational purposes only and does not replace professional medical advice. Always talk with your healthcare provider before making changes to your treatment or care. The Glaucoma Community does not endorse specific treatments, providers, or products.