OCT or Optical Coherence Tomography is changing the way our Optometrists can examine and help protect eye health.
These machines provide much more detailed examinations and provide earlier detection of many eye conditions including glaucoma and macular degeneration as well as providing peace of mind to patients to patients who otherwise would need referring onto long NHS waiting lists when something suspect is found on standard eye testing.
What is OCT and how does it work?
Optical Coherence Tomography is a non-invasive imaging scan. It is the optical equivalent of ultrasound: ultrasound uses sound waves to bounce of layers of tissue of varying reflectivity to build up an image; OCT works in a similar way. We can then see a cross-sectional image of the retina, thickness measurements are taken and maps formed, which are all important in diagnosing and monitoring eye diseases.
The retina is the light sensitive membrane at the back of the eye that detects images and lets us see – a bit like the film in a camera. With OCT your optometrist can see each of the retina’s distinctive layers enabling earlier detection of many eye conditions.
Considering the eye as an iced cake is a great way to think about how OCT works. The top layer of the retina is the icing and without OCT, normal viewing of the eye (using a slit lamp microscope or retinal photography) Optometrists can only see the icing without being able to see what sits behind or inside the cake. Are the layers all even? Is there the right amount of jam, or has it leaked into the sponge? Is there anything hiding in the layers of that cake?
Without looking inside the cake, only looking at the icing, you just don’t know. Luckily we don’t need to cut into the eye to find out what is going on in the layers under the surface of the retina as the OCT simply shows us on the screen.
What happens during an OCT appointment?
During an OCT scan you will sit in front of the OCT equipment and rest your head on a support to keep it as still as possible. The machine will then scan your eye, without touching it. You will simply see a few red lines moving around and you will be asked to looks at a dot. Scanning takes about 5 – 10 minutes in total – but the actual scan itself is just a couple of minutes.
If you have an OCT scan immediately preceding your eye examination then the optometrist will be able to show you the fascinating images on the screen in the consulting room. Most people don’t require any drops to have the scan either, but the odd few patients have too small pupils to get a good view so dilating drops allow for a better view and therefore results.
Why should you have an OCT scan?
OCT scans can identify many more conditions than standard examination and conditions before symptoms start to occur. Often the symptoms of eye conditions are when damage has already started occur. More detailed assessment also allows for better referrals and directed to the exact clinic and treatment that person needs meaning potentially much less stress and worry while waiting for an initial appointment at the hospital. It also allows for many patients to avoid needing a referral to hospital all together and just have monitoring at their convenience. Conditions such as glaucoma and macular degeneration, diabetic retinopathy as well as many, many more can all be detected earlier and better managed with OCT technology.
OCT further more allows an individual to know exactly how their eyes were at a point of time and therefore monitor and observe changes over subsequent visits and years again all allowing for much earlier detection and prevention of eye pathology and damage.
Our OCT assessment in included with enhanced sight test to patients on our VeyeP eyecare plan.
Ask your optician about OCT testing when you next have your eyes tested.