During your sight-test our aim is to assess your vision and, if necessary, use spectacles (or contact lenses) to make your vision as clear as possible. Our other aim is to assess the health of your eyes and detect any defects – OCT (which stands for Ocular {or sometimes Optical} Coherence Tomography) is an invaluable tool used to achieve this.
As technology has improved it has helped us to carry out our assessments with much more accuracy. OCT is a perfect example of this and it has been a major leap forward in helping eye-care professionals assess patients eye health. OCT is often not available in high street opticians, it is more commonly found in hospital eye departments so we are very fortunate to have such a high-tech piece of equipment. OCT is quick (taking just a few minutes), painless and very safe procedure which uses light to scan the eye to build up a picture for us to view. The picture we see is a cross section of the eye.
During a conventional sight-test we use a torch (called an ophthalmoscope) to view inside the eye. A camera may also be used to take a photograph to view the inside of the eye. If you imagine that the eye is a ball with a hole (the pupil) at the front. We shine the ophthalmoscope through the pupil to light up the inside of the eye (the camera flash does the same thing during photography). This allows us to view the internal structures of the eye to make sure they look normal. One of the main areas we look at is the retina. The retina is like wallpaper which lines the inside of the eye. The retina is a very complex structure consisting of 10 layers. The layer we see with the ophthalmoscope and the camera is the first (innermost) layer.
By using the OCT, we can view all 10 layers and beyond that –view underneath the retina. Numerous defects in the retina are not always seen when viewing the first retinal layer with the ophthalmoscope or camera. By allowing us to view much more than just the first layer, the OCT allows us to detect more defects (macular degeneration, retinal detachments, retinal holes and tears to name just a few).
One of the most important layers in the retina is the Nerve Fibre Layer. Glaucoma is an eye disease which damages the nerve fibres in the eye. The OCT allows us to measure the thickness of the Nerve Fibre Layer (down to the last micrometer - which is 0.001mm!). A very early sign of glaucoma is a subtle thinning of the Nerve Fibre Layer. The OCT detects this subtle change and so allows us to detect glaucoma at an earlier stage than in a conventional sight-test.
Like all things health-related, the earlier a defect is detected the more effective the treatment is – this is the same in glaucoma. ‘Nipping in the bud’ any eye defects is obviously beneficial. The OCT allows us to do this.
All OCT results are electronically stored in your records so as well as giving us a better view of the eye on the day of your sight-test, it also allows to accurately monitor the eye to detect any changes in the future.
As a conclusion to this I hope it is clear that yes, you will definitely benefit from having OCT at each sight-test you have.
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