Under Pressure

Your eyes may feel completely normal, yet silent damage could be occurring without any warning signs. Eye pressure plays a crucial role in maintaining vision health, and understanding what is considered normal can help identify potential risks. Millions of people have elevated eye pressure without realizing it, making regular eye exams essential for early detection of glaucoma.

Not too high, not too low

Eye pressure, also called intraocular pressure (IOP), refers to the fluid pressure inside the eye. It is typically measured in millimeters of mercury (mmHg), much like blood pressure. The normal range generally falls between 10 and 20 mmHg. However, eye pressure isn’t a fixed number—it fluctuates throughout the day and can be influenced by various factors, including body position and overall health. Some people may have slightly higher or lower pressure without experiencing any problems, while others may develop glaucoma even within the normal range.

The silent threat

Glaucoma is an eye disease that damages the optic nerve, often due to increased eye pressure. However, the relationship between eye pressure and glaucoma is not always straightforward. Some people with high eye pressure never develop glaucoma, while others with normal pressure may still experience vision loss. This condition, known as normal-tension glaucoma, occurs when the optic nerve is damaged despite pressure levels falling within the standard range.

Because glaucoma often progresses without noticeable symptoms in its early stages, many individuals remain unaware of the condition until significant vision loss occurs. This is why routine eye exams are crucial—they allow doctors to assess eye pressure, examine the optic nerve, and detect any signs of damage before vision is affected.

When does eye pressure become a concern?

High eye pressure, also known as ocular hypertension, typically refers to readings above 21 mmHg. While not everyone with high pressure develops glaucoma, persistent elevation increases the risk. Certain factors make some individuals more susceptible to pressure-related damage, including:

• A family history of glaucoma
• Being over the age of 40
• Having diabetes or high blood pressure
• Thin corneas, which can lead to underestimated pressure readings

If left untreated, high eye pressure can gradually damage the optic nerve, leading to irreversible vision loss. The challenge is that most people don’t experience symptoms until the damage is already done.

Why regular eye exams matter

Since pressure-related eye damage is often silent, regular eye exams are the best way to detect problems early. Eye doctors use a test called tonometry to measure eye pressure, along with other tools to assess the health of the optic nerve and visual field. If needed, treatment options such as medicated eye drops, laser therapy, or surgery can help lower pressure and reduce the risk of vision loss.