Ocular Hypertension (High Eye Pressure)

What ocular hypertension means

The front of the eye is filled with a clear fluid, the aqueous humor. It is made continuously behind the iris and drains out through a mesh-like tissue (the trabecular meshwork) at the angle where the iris meets the cornea. The balance between production and drainage sets the intraocular pressure (IOP).

• Normal eye pressure: about 10 to 21 mmHg, with an average of about 15 to 16.
• Ocular hypertension: pressure consistently above 21 mmHg in one or both eyes, with an open drainage angle, a healthy optic nerve and a normal visual field.

When drainage slows, pressure rises. Over time, high pressure can damage the optic nerve at the back of the eye, causing glaucoma. Ocular hypertension is the stage before any damage has occurred.

Ocular hypertension vs glaucoma

Causes and risk factors

Most ocular hypertension has no single cause; the drainage tissue simply works less efficiently. Contributing factors include:

• Age over 40
• Family history of glaucoma or high eye pressure
• African, Caribbean or Hispanic ancestry
• Steroid medicines: eye drops especially, but also tablets, inhalers, nasal sprays and skin creams near the eyes. About 1 in 3 people have some pressure rise with steroid eye drops.
• Eye conditions: pigment dispersion syndrome, pseudoexfoliation, inflammation inside the eye (uveitis) and previous eye injury
• High myopia (short-sightedness)
• Diabetes and high blood pressure, with a weaker link

Symptoms

Ocular hypertension has no symptoms. The eye does not hurt, look red or see differently. That is why regular eye exams matter, especially after age 40 or with a family history.

Sudden pain, redness, headache and blurred vision with halos is a different and much rarer problem: acute angle-closure glaucoma, an emergency.

How it is diagnosed

1. Tonometry: measures eye pressure. The Goldmann applanation test, using numbing drops and a blue light, is the gold standard. The "air puff" test is used for screening.
2. Repeated readings: pressure varies through the day, often highest in the early morning, so a single high reading is confirmed on another visit.
3. Pachymetry: measures corneal thickness. A thick cornea can make the pressure read falsely high; a thin cornea makes it read falsely low and raises glaucoma risk.
4. Gonioscopy: a special lens checks that the drainage angle is open.
5. Optic nerve exam and OCT scan: a detailed scan of the optic nerve and nerve fiber layer to detect early damage.
6. Visual field test: checks side vision for early glaucoma loss.

Risk of developing glaucoma

The large Ocular Hypertension Treatment Study found that about 9.5% of untreated people with ocular hypertension developed glaucoma over 5 years, compared with about 4.4% of those treated with eye drops. Risk is higher with:

• higher pressure, especially above 25 to 30 mmHg
• a thin cornea
• older age
• a larger cup in the optic nerve
• family history of glaucoma
• African ancestry

Eye doctors use these factors to estimate each person's risk and decide whether treatment is worthwhile.

Treatment

Monitoring

People at low risk are often monitored without treatment, with pressure checks, optic nerve scans and visual fields every 6 to 12 months at first, then less often if stable.

Eye drops

Treatment is usually recommended when pressure is 24 mmHg or above with other risk factors, or about 30 mmHg or above regardless. The goal is usually to lower pressure by about 20% to 30%.

• Prostaglandin analogs (such as latanoprost): first choice, once at night. Side effects include red eyes, longer eyelashes and, rarely, darkening of the iris.
• Beta-blockers (such as timolol): avoided in people with asthma, COPD or a slow heart rate.
• Alpha agonists, carbonic anhydrase inhibitors and rho kinase inhibitors: other options or add-ons.

Press gently on the inner corner of the eye for a minute after each drop to reduce absorption into the body.

Laser

Selective laser trabeculoplasty (SLT) is a quick, outpatient laser that improves drainage. It is now a recommended first-line alternative to drops and avoids daily medicine. Its effect can wear off after several years, and it can be repeated.

Stopping steroids

If steroids raised the pressure, stopping or switching them often brings it back down within weeks.

Living with ocular hypertension

• Use drops as prescribed and keep every follow-up appointment.
• Tell any doctor prescribing steroids that you have high eye pressure.
• Regular aerobic exercise modestly lowers eye pressure. Avoid prolonged head-down positions, such as some yoga inversions, if your pressure is high.
• Ask relatives over 40 to have eye exams.

Frequently asked questions

What is normal eye pressure?

Normal eye pressure is roughly 10 to 21 mmHg. Pressure varies through the day and between people. Corneal thickness also affects the reading, so eye doctors interpret it together with other tests rather than relying on a single number.

Does ocular hypertension always lead to glaucoma?

No. Most people with ocular hypertension never develop glaucoma. Without treatment, about 1 in 10 develop it within 5 years. Treatment roughly halves that risk. Your individual risk depends on pressure level, corneal thickness, age and family history.

Can stress or caffeine raise eye pressure?

Caffeine can raise eye pressure slightly for an hour or two, which matters little for most people. Stress has a small, short-lived effect. Steroid medicines, genetics and the drainage system's efficiency matter much more. Moderate coffee intake is generally considered fine.

Can ocular hypertension be cured?

It cannot usually be cured, but it can be controlled. Eye drops or laser lower pressure effectively, and steroid-induced pressure often returns to normal after stopping the steroid. Lifelong monitoring is recommended because pressure and glaucoma risk can change over time.

What are the symptoms of high eye pressure?

Usually none. Ocular hypertension does not cause pain, redness or blurred vision, which is why it is found only at eye exams. Severe eye pain, redness, blurred vision and halos come from acute angle-closure glaucoma, which is an emergency.