Have you ever seen obscure mark floating in your field of vision? It looks like a small, transparent blob or a piece of fine fibre - but every time you move your eye to get a closer look, the blob swims away.
That, ladies and gentleman, is what's known as a 'floater'.
But unlike something left in the toilet that just won't flush, these floaters are actually small pieces of debris that float in the eye and cast shadows on to the light-sensitive retina.
According to the NHS, said debris can be found in the vitreous humour, which is a clear, jelly-like substance that fills the space in the middle of the eyeball.
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They can be different shapes and sizes and may look like:
- tiny black dots
- small, shadowy dots
- larger cloud-like spots
- long, narrow strands
They are largely harmless and do not require treatment, but sometimes they can indicate retinal damage.
Watch the video above for more info.