If you've been referred for a glaucoma assessment, you might be wondering what actually happens in the room. Will it hurt? How long does it take? What are they looking for?

Let's walk through the appointment together, test by test. You'll see it's straightforward, painless and designed to build a complete picture of your eye health.

Why glaucoma tests matter

Glaucoma is often called the silent thief of sight. It damages the optic nerve gradually, and you might not notice any symptoms until your vision is already affected. That's why glaucoma tests are so important.

Your consultant uses these tests to spot early signs of damage, track any changes over time and decide on the best way to protect your sight. The earlier we catch it, the more options you have.

What happens when you arrive

You'll start with a chat. Your consultant will ask about your family history, any eye symptoms you've noticed and your general health. Certain conditions like diabetes and high blood pressure can affect your eyes, so it all helps build the picture.

Then you'll move on to the clinical tests. Each one looks at a different aspect of your eye health, and together they give your consultant everything they need.

Eye pressure measurement

This is usually the first test. Your consultant measures the pressure inside your eye, known as intraocular pressure or IOP. High pressure can be a warning sign for glaucoma, though not everyone with high pressure develops the condition.

You'll rest your chin on a small support while a gentle puff of air is directed at your eye, or a small probe touches the surface after anaesthetic drops. It takes seconds and you won't feel any pain.

Visual field tests explained

Visual field tests check your peripheral vision, the areas you see out of the corner of your eye. Glaucoma often affects these outer zones first, so this test is crucial.

You'll look into a bowl-shaped machine and focus on a central point. Small lights flash in different spots around your field of vision, and you press a button each time you see one. It sounds simple, and it is. You might find your eyes get a little tired, but that's normal.

The test maps out any blind spots or areas where your vision has dimmed. Your consultant compares the results to previous tests if you've had them, watching for any progression.

OCT scans: a closer look at your optic nerve

An OCT scan, or optical coherence tomography, gives your consultant a detailed cross-section image of your retina and optic nerve. Think of it like an MRI for your eye.

You rest your chin on a support again and look at a target inside the machine. It takes just a few minutes and there's no contact with your eye. The scan shows the layers of your retina in fine detail, so your consultant can spot thinning or damage that might suggest glaucoma.

According to Glaucoma UK, OCT imaging has transformed how we monitor the condition, picking up changes much earlier than older methods could.

Other glaucoma tests you might have

Depending on your situation, your consultant might use a few additional tests. Gonioscopy examines the drainage angle in your eye, the channel where fluid flows out. A special lens sits gently on your eye after anaesthetic drops, and it helps determine what type of glaucoma you have.

Pachymetry measures the thickness of your cornea, the clear front layer of your eye. Corneal thickness affects pressure readings, so knowing yours helps your consultant interpret your results accurately.

You might also have optic nerve imaging from different angles or a test that checks how your pupil responds to light. None of these are painful, and your consultant will explain each one as you go.

How long does a glaucoma assessment take?

Plan for around an hour, sometimes a little longer if you need extra tests. You're not rushed. Your consultant wants to gather thorough information and answer any questions you have.

Some tests require eye drops that blur your vision temporarily, so bring someone to drive you home if possible. The drops wear off within a few hours.

What happens after your glaucoma tests?

Your consultant will go through the results with you. They'll explain what they've found, whether any treatment is needed and what the next steps look like. If you have glaucoma, starting treatment early makes a real difference.

You might be referred for further monitoring, prescribed eye drops to lower your pressure or advised on lifestyle changes that support your eye health. For a broader overview of keeping your eyes healthy, take a look at our guide to an eye health check.

Questions to ask at your appointment

You're welcome to ask anything. Here are a few to consider: What do my results show? Do I need treatment now or just monitoring? How often should I come back for tests? Are there things I can do at home to protect my vision?

Your consultant is there to help you understand your eye health and feel confident in your care plan. There's no such thing as a silly question.

Booking your glaucoma assessment

If you've been referred or you're concerned about your eye pressure or family history, don't wait. Early detection is your best tool.

At LondonOC, every assessment is carried out by an experienced consultant ophthalmologist. You'll have their full attention, time to ask questions and a clear plan tailored to you. We combine advanced diagnostic technology with a warm, unhurried approach, so you feel looked after from the moment you arrive.

Glaucoma tests might sound daunting, but once you know what to expect, they're much less worrying. You're taking an important step to protect your sight, and we're here to support you every step of the way.