“Seeing beneath the surface is essential to the health of your eyes…”

Optical coherence tomography (OCT)

Interested in having an OCT scan? You’ll find lots of information here including how to book it alongside your eye test.

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What is an OCT scan?

An optical coherence tomography scan (often referred to as an OCT scan) allows us to see what’s going on beneath the surface of the eye, allowing us to examine what’s going on with your eyes in finer detail.

Consider it like a cake: we can view the top of the cake and the icing using 2D digital retinal photography (fundus camera), but the 3D image created by an OCT scan cuts the cake in half and turns it on its side, allowing us to see all of the layers inside.

Our optometrists can then map out and assess the thickness of these layers to gain a better picture of your overall eye health.

OCT scans can aid in the early detection of vision-threatening eye diseases. Glaucoma can be identified up to four years before symptoms appear.

If you have any of the following symptoms, you may require a second opinion:

An OCT is not the same as an eye exam. An eye exam examines your vision as well as your eye health. Taking a picture of the back of the eye (digital retinal photography) is a common part of this, but an OCT scan goes a step further, allowing your optician to examine even deeper into your eyes and the structures within them.

When an optician tests your eyes, an OCT scan offers them a better idea of your eye health.

Traditional fundus test image

OCT scan image


People over the age of 25 who wish to learn more about their eye health, as well as those who have diabetes, glaucoma, or a family history of eye illness, should get an OCT scan.

We still recommend an OCT scan with every eye exam, even if your vision and eye health are great. Your optician will appreciate having a baseline image on file so they can track any changes over time. It’s the same as when we use digital retinal photography to take a picture of the back of your eye.

So the next time you go in for an eye exam, your optician will be able to compare your previous photographs as well as measurements to averages, and may be able to detect even the tiniest change in the eye’s structures. This could help detect early signs of eye diseases such as glaucoma, diabetic retinopathy, and macular degeneration before symptoms appear.

This means that these disorders can be handled before they worsen, perhaps preventing vision loss. For a short scan, that’s a really respectable outcome.

What is the price of an OCT scan?

Because OCT scans are not included in your eye exam, an extra fee may apply: a fee of £24 pounds will be charged.

Is it more time consuming than a standard eye exam?

An OCT scan just takes a few seconds, and your optician will review the results with you during your eye checkup.

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OCT scanning is useful for ensuring that your eyes are healthy and can be repeated for comparison over time. This makes it especially useful for spotting potentially sight-threatening disorders that don’t usually cause symptoms until they start to affect your vision.

OCT allows your optician to detect subtle changes in the vitreous (the jelly-like substance that fills the eye), retina (the light-sensitive layer at the back of the eye), macula (the area at the centre of the retina responsible for our central vision), and optic nerve over time (transmits light impulses to the brain to produce the images we see).

These are some of them:

  • Glaucoma
  • Diabetic retinopathy is a kind of retinopathy caused by diabetes.
  • Retinal detachment
  • Macular degeneration is a condition that affects people as they get older.
  • Hole in the macular

In fact, compared to standard approaches, an OCT scan can diagnose glaucoma up to four years earlier.

What is optical coherence tomography and how does it work?

  • An OCT scan uses light to obtain over 1,000 photos of the back of your eye and beyond, all the way back to the optic nerve, in only a few seconds.
  • We develop a layered image that provides us with an extremely exact view of your eye and its components, allowing us to assess your eye health. After that, the photos will be saved so that we can track changes over time.

Do I still need an OCT scan if I undergo a diabetes checkup every year?

  • Yes, both the diabetes screening check and the OCT entail obtaining photographs of the back of the eye, but there are important distinctions.
  • A fundus photograph, also known as digital retinal photography, is taken during a diabetic check. It is an image of the surface of the back of the eye (the retina). OCT scans allow us to examine the numerous layers beneath the retina's surface, allowing us to detect changes in eye health sooner than if we only looked at the surface.
  • Not only do OCT scans aid in the discovery of diabetes-related eye disorders, but they also aid in the detection of a variety of other eye problems.

OCT scans are recommended for anyone aged 25 or older. It’s really helpful for your optician to take readings and track them every time you come in and see us in order to best safeguard your eye health.

Yes – as well as checking for a range of eye conditions that may not be under review at the hospital, it will provide an up to date appraisal of your eye health. Your optician does not usually have access to the results from your hospital examinations and the scan will give a more rounded analysis of your eye health.

No, it’s very different from having an MRI. It’s more like having a photograph taken of your eye, you simply sit in a chair and look into the OCT device for a matter of seconds. You don’t have to lie down like an MRI scan.

None. OCT uses a completely safe laser light source, so there are no side effects or risks associated with an OCT procedure.

An OCT scan is in addition to your eye test and carries a small fee of £10.

“Seeing beneath the surface is essential to the health of your eyes…”

What is OCT?

OCT – Ocular Coherence Tomography – is an advanced eye scan for people of all ages. Similar to ultrasound, OCT uses light rather than sound waves to illustrate the different layers that make up the back of your eye. The OCT machine captures both a fundus photograph and a cross-sectional scan of the back of the eye at the same time.

The scientific stuff!

Using a Topcon state-of-the-art 3D OCT camera, your optometrist will take both a digital photograph and a three dimensional cross-sectional scan of the back of your eye in one sitting. This allows us to instantly diagnose a number of common conditions. The scan is non-invasive, painless, simple and quick. What’s more, the software can automatically detect even the subtle changes to the retina with every eye test you take. This gives you an invaluable ongoing record of the health condition of your eyes.

What can the scan check for?

Common conditions identified through regular OCT screening include:

Age-related Macular Degeneration (AMD)

Macular degeneration causes the gradual breakdown of the macular (the central portion of the eye). OCT can identify this condition and its type (there are two types, wet and dry) and also monitor its progress, for example if you are undergoing treatment for such a condition. Unfortunately the risk of developing macular degeneration increases with age, and it is the most common cause of vision loss in individuals over the age of fifty.


Diabetic retinopathy is a major cause of visual impairment among adults. Here in the UK, more than two million people have been identified as having diabetes. OCT examination enables early detection, which greatly improves the success rate of treatment.


Glaucoma damages the optic nerve at the point where it leaves the eye. Recent statistics suggest that some form of glaucoma affects around two in every 100 people over the age of 40. The danger with chronic glaucoma is that there is no pain and your eyesight will seem to be unchanged, but your vision is being damaged. An OCT examination will confirm if you are at risk, or indeed what state of glaucoma you may have.

Macular Holes

A macular hole is a small hole in the macular – the part of the retina which is responsible for our sharp, detailed, central vision. This is vision we use when we are looking directly at things, when reading, sewing or using a computer. There are many causes of macular holes. One is caused by vitreous detachment, when the vitreous pulls away from the back of the eye and sometimes it does not “let go” and eventually tears the retina, leaving a hole. Extreme exposure to sunlight (for example staring at the sun during an eclipse) can also cause a macular hole to develop.

Vitreous Detachments

Vitreomacular traction can clearly be diagnosed through OCT providing invaluable information about the current relationship between the vitreous and the retinal surface of the eye. As people get older the vitreous jelly that takes up the space in our eyeball can change. It becomes less firm and can move away from the back of the eye towards the centre, in some cases parts do not detach and cause “pulling” of the retinal surface. The danger of a vitreous detachment is that there is no pain and your eyesight will seem unchanged but the back of your eye may be being damaged.

If you have any questions or would like to find out more about OCT screening, please contact a member of staff in any of our practices.