If eyes emitted light, could they still see?

DefinitelyNotAFae
2025-01-28T02:11:55Z

Ok, this is one of those thoughts I have in my brain and that I can't quite get rid of.
It breaks down into a couple of questions. For the purposes of this, I'm aware that what eyes see is the reflection of light bouncing off objects, but I'm curious the impact on the visibility of both objects and other lights.

A. If eyes emitted any light, could they still see anything at all?
B. If eyes emitted, for example, red light, could they see everything except red items? What about red lights? Does this change if the light is green or violet?
B.1. If they can't red things would they just be invisible?
B.2. If they can't see red lights, would it matter if the red light they're seeing is brighter or dimmer, and would it still be an invisible/blank space?
C. I'm not sure how infrared interacts here but I know animals that sense infrared do emit it, is there a reason that's different, if it's different.

The internet is mostly not super helpful with this, since eyes don't emit light, just reflect it and look glowy, but yeah, anyway... thanks for entertaining my weird fixation.

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