Eye health
5 min read
What an OCT scan actually shows
Ten seconds, no puff of air, and a cross-section of the back of your eye. Here is what we look at on the screen beside you.
Written by
Priya Lal
An OCT scan takes about ten seconds. You rest your chin, look at a small light, and the machine builds a cross-section of the layers at the back of your eye, a bit like an ultrasound but made with light.
What we look for
The nerve fibre layer around the optic nerve thins years before glaucoma affects your sight. The macula, the part you read with, shows early swelling or deposits long before you notice blurring. Diabetes leaves small leaks in the retina’s blood vessels.
We keep every scan, so next time we compare like with like. A change of a few microns between two visits tells us more than any single picture.
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