What Is An OCT Eye Test?

testing room

For anyone over the age of 25 having regular eye examinations, your optician will request that you have an OCT eye test done. Normally when we chat to you about your optical health, we don’t get too technical; but when it comes to an OCT, (or a coherence tomography test), it is necessary to get a little sciencey when we explain. Don’t worry though, we’ll keep it as simple as we can.

Why Have an OCT Test and What is its Purpose?

Like any disease, illnesses of the eyes tend to creep up on you, with many conditions not demonstrating any symptoms at all in the early stages. Your vision could seem to be absolutely normal to you, which is why it’s a good idea to keep up with your optical health checks so your optician can stay on top of what may be happening beneath the surface. With additional tests, such as the OCT, they can get a better understanding of overall health. He or she will glean a picture of the retina and be able to map out the layers while measuring the all-important thickness of them. The optic nerve can also be seen during this kind of scan and therefore any relevant issues can also be picked up.

Even with healthy vision, you may be asked to undergo one of these scans. This is to give the optician baseline measurements of your optical health, so that future tests can be compared and changes can be more easily detected.

How Does This Scan Work?

So, here is where we get a little more technical. It’s all about the light waves that pass from the camera through the eye and into the retina. The 3D images are taken just as they would be in an ultrasound and your optician can interpret them straight away. The key thing for you to remember is that this whole process is painless. All you will be asked to do is to sit in front of a small machine and rest your chin on a support. A large instrument attached to the machine then scans your eyes without any need for it to touch you.

Both eyes will be checked, one at a time. Some people are a little dazzled by the intense flash of light that is emitted when the images are taken, but this disappears very quickly.

How Long Does the Scan Take?

The actual process takes little more than a few seconds on each eye. The whole thing can be done in less than a minute (you could say it is all over in a ‘blink of an eye!’), which is amazing really when you think about the information this process can provide.

What Can an OCT Detect?

Here we come to the reason why you would have this test and what it can help your optician identify. At the very least the scan can reassure you that your eyes are healthy, which is great news, but more importantly this technology can pick up the early signs of some quite nasty potentially sight threatening diseases, too. Your eyes, and specifically the health of the retina, can help your optician detect conditions that are related to your overall health and then of course guide you towards early intervention. Great news all round!

Many of these associated conditions begin to form at the back of the eye and the subtle changes picked up by the scan can be identified over time. Changes include alterations to the vitreous (the jelly material that fills the eye), the retina (the bit at the back of the eye that is sensitive to light), the macula (responsible for central vision and lying in the centre of the retina) and the optic nerve (this transmits lights impulses to the brain and is therefore responsible for the images we see).

The conditions associated with these changes include:

Diabetic retinopathy
Age-related macular degeneration
Macular hole
Detached retina

Interesting Fact: An OCT scan can help to detect glaucoma up to four years earlier than traditional methods. If you have this issue you will know how incredible this is!

Is the Procedure Safe?

The OCT is a safe scan that is non invasive, quick and painfree. There are no known side effects or other complications. The technology only uses reflected visible light from a low-power laser to take the images, and the process is very much like an ultrasound but instead of sound waves, light waves are used.

You may be worried if you have a pacemaker or metallic implant, but there is no need. These do not interfere with the technology and vice versa. Hearing aids can also be worn throughout the process.

If you’re worried about the test, just chat to your optician and they will be able to talk through things with you and hopefully allay any fears. The benefits of including the process in your sight test are vast, so it comes highly recommended.

What is the Upshot?

Any optician worth their salt will offer the OCT scan at every sight test so that you can rest assured that your eye health stays in the best possible condition for as long as possible. You also have the peace of mind that should any deterioration begin, it will be picked up early and treated accordingly with the best possible outcome.

If you’d like to discuss this further or book an appointment for an exam with one of our highly experienced team, get in touch with us.