Why do People Notice Eye FloatersWe don't actually notice the eye floaters themselves, but rather the shadow they cast into the retina.
You might be wondering why you see floaters when looking against a light background, yet not a darker one. The reason is simple: As a background is more lighter colored, the floater's shadow becomes more apparent to the brain.
In case you're wondering, part of the reason floaters are not seen in darker places is because the brain has actually learned to ignore them. They are there.
A common sensation many floater sufferers have is that of being watched. As you have eye floaters moving around your vitreous, you might think seeing someone "out of the corner of your eye". However, if there's no one there it's probably just a floater.
To see what eye floaters actually look like visit the Images or the eye diagram.
Go back to What are Eye Floaters? or read How Common are Eye Floaters?