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OCT (Optical Coherence Tomography)

What is an OCT scan?

Optical Coherence Tomography (OCT) is a quick, painless scan, with countless benefits for your eyesight as well as your health.

OCT scans are recommended for those aged 25 or over, who want to know more about their eye health, or have diabetes, glaucoma, or have family history of eye disease. The layers at the back of the eye can be difficult to see with standard equipment. An OCT scan displays vibrant colour pictures of these ultra-thin membranes.

Any fluid detected beneath the layers at the back of the eye will be revealed through an OCT scan. The fluid can be measured and our optometrists can then make additional referrals if necessary.The fluid inside the eye is analysed in 3D, which helps us establish if there has been any separation within the eye that could be responsible for floaters.

The optic nerve scans provide detailed information about the quantity and thickness of the nerve fibre layers and immediately alert us to any thinning areas. This can help us detect any damage due to glaucoma. We can also review the chambers inside the eye and evaluate the risk of closed angle glaucoma, providing us valuable time to suggest treatment options.

We can assess the thickness of your eye's surface, which is very useful information to have if we discover the pressure within the eyes is higher than normal. Repeat OCT scans, even on healthy eyes, help us to monitor eye health over time, meaning any subtle changes can be immediately detected and treated if necessary.

Do I need an OCT scan?

The routine sight test is good at detecting signs of eye disease. However, it can sometimes be difficult for your optometrist to decide whether the back of your eye is normal or if there is an abnormality that needs treatment.

OCT scans can also be used to monitor the progress of signs of ageing or wear and tear in your eye, and some optometrists recommend taking an OCT scan to use as a record of what is normal for you. They can then compare any scans taken at future appointments with this baseline scan to help them detect subtle changes which could be an early sign of some eye conditions.

How does the OCT scan work?

You will be asked to sit in front of the scanner and rest your chin on the chin rest. The machine will scan your eyes using low powered laser light to take images of the structures inside your eye, most commonly your retina – the thin layer of tissue that lines the back of the eye – and your optic nerve. It scans your eye without touching it. The scan doesn’t hurt, but some people may find the bright light a little uncomfortable. The process is over in a few seconds. When it is finished, your optometrist will go through your results with you.

Is an OCT scan safe?

The OCT scanner is CE marked and the low powered laser light is safe, and cannot harm your eye. The OCT scan is suitable for use with people fitted with pacemakers or metallic implants and you can wear your hearing aid throughout the procedure.