Tonometry

Overview

Tonometry is a quick, painless test that measures the pressure inside your eye. This pressure is called intraocular pressure (IOP). High eye pressure can damage the optic nerve and lead to vision loss, so tonometry is an important test for checking eye health.

Yes, tonometry is a common and routine test in eye care. It is used in many eye exams, especially for adults over 40 or those with risk factors for glaucoma.

Tonometry is performed on people of all ages, but it is especially important for older adults, people with a family history of glaucoma, those with high blood pressure or diabetes, and anyone with eye symptoms or vision changes.

Symptoms

Common symptoms

• Tonometry itself does not cause symptoms. It is a test, not a condition. However, if your eye pressure is high, you usually have no symptoms at first. That is why regular eye exams are important.

Symptoms in children

• Tonometry is sometimes done in children if there is a risk of glaucoma (for example, after an eye injury or if they have certain medical conditions). The test is adjusted to be as comfortable as possible.

Symptoms in older adults

• Tonometry is common in older adults because the risk of high eye pressure and glaucoma increases with age.

Causes

Main causes

• High eye pressure (intraocular pressure) can be caused by too much fluid (aqueous humor) in the eye. This fluid normally drains through a mesh-like channel. If the channel gets blocked or is not working well, pressure builds up.
• Other causes include eye injuries, certain medications (like steroids), and some eye conditions.

Risk factors

• Age over 40
• Family history of glaucoma
• Being of African, Caribbean, or Asian descent
• High blood pressure or diabetes
• Eye injuries or surgery
• Long-term use of steroid medications

When to see a doctor

See a doctor urgently if:

• If you have sudden eye pain, vision loss, or severe eye redness, seek emergency care immediately.

Book a routine appointment if:

• Get a routine eye exam every two years if you are over 40, or as often as your eye doctor recommends. Tonometry is usually part of this exam.

Diagnosis

Tonometry is a test used to measure eye pressure. It is part of a comprehensive eye exam. Your doctor may perform other tests (like checking your optic nerve, visual field, and corneal thickness) to fully assess your eye health.

Tests that may be done

• Applanation tonometry: A device gently touches the eye to measure pressure, after numbing drops are put in.
• Non-contact (air-puff) tonometry: A small puff of air is blown at the eye. No contact with the surface.

What to expect at your appointment

The test takes just a few seconds. You may feel a slight pressure or a puff of air. Numbing drops are used for applanation tonometry, so you won’t feel pain. You can go home straight after.

Treatment

If tonometry shows high eye pressure, your doctor will discuss treatment options. Treatment aims to lower eye pressure to prevent damage to the optic nerve. This is usually a long-term plan.

Self-care at home

• Attend all follow-up eye exams as recommended.
• Take any prescribed eye drops exactly as directed.
• Inform your doctor about any other medications you are taking.
• Wear eye protection during sports or activities that could injure your eyes.

Medical treatments

Medical treatment for high eye pressure typically begins with prescription eye drops that help reduce fluid production or improve drainage. If drops are not enough, laser procedures (such as selective laser trabeculoplasty) can help open the drainage channels. In some cases, oral medications may be used. Your doctor will choose the best approach for you. Always follow your doctor’s instructions and do not stop treatment without guidance.

When is surgery considered?

Surgery may be considered if eye pressure remains high despite medications and laser. Surgical options (like trabeculectomy or drainage implants) create a new way for fluid to drain from the eye. Your eye specialist will discuss the risks and benefits.

Living with this condition

If you have high eye pressure or glaucoma, you can live a full, active life. The key is regular monitoring and sticking to your treatment plan. Your doctor will schedule follow-up visits to check your eye pressure and vision.

Lifestyle tips

• Maintain a healthy weight and stay physically active, but avoid heavy lifting or inverted yoga poses that might increase eye pressure.
• Protect your eyes from injury with safety glasses when needed.
• Tell your eye doctor about any new symptoms or changes in your vision.

Diet and exercise

A balanced diet rich in vegetables and fruits may support overall eye health. Some studies suggest that drinking plenty of water in small amounts throughout the day can help, but avoid drinking large amounts quickly, as that can temporarily raise eye pressure. Regular moderate exercise is generally safe and beneficial.

Mental health and emotional wellbeing

Living with a condition that could affect your sight can be worrying. It is normal to feel anxious or stressed. Talk to your doctor about these feelings. Many people find support groups or counselling helpful.

Prevention

You cannot always prevent high eye pressure, but regular eye exams can catch it early before damage occurs. If you have risk factors, talk to your doctor about how often to have your eyes checked. Controlling conditions like high blood pressure and diabetes may also help.

Screening programmes

Regular eye exams that include tonometry are a form of screening. Many organisations recommend eye exams every two years for adults over 40, and more often if you have risk factors.

Complications

If left untreated

• If high eye pressure is not treated, it can damage the optic nerve, leading to glaucoma and permanent vision loss.
• Vision loss from glaucoma is irreversible, which is why early detection and treatment are so important.

Long-term outlook

With regular monitoring and treatment, most people with high eye pressure can protect their vision for many years. Tonometry helps your doctor keep track of your eye pressure so that adjustments can be made if needed. The outlook is good when you work closely with your eye care team.

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