Phosphenes
Sensations of light produced without light entering the eye — the sparks and grids you see when you press on a closed eyelid, or when a cosmic ray passes through your retina.
Full definition of Phosphenes →:: COMPARE ::
PhosphenesvsFloaters
The short answer
Floaters are real shadows, cast on the retina by debris drifting in the vitreous. Phosphenes are light with no light behind it. One is an object; the other is a firing.
Side by side
| Aspect | Phosphenes | Floaters |
|---|---|---|
| Physical object | None | Yes |
| Cause | Neural firing | A shadow |
| Moves with the eye | No | Drifts |
| Producible on purpose | Yes | No |
What each one means
Floaters
The contrast above sets out how Floaters differs from Phosphenes on the points that actually matter.