Why do we see the light even when our eyes are closed?

Question

Are our eyelids weaker?

Why do we wake up when the lights are switched on?

Answer 1

Depends on how bright the light is!

Answer 2

Our eyelid skin is very thin, allowing light to penetrate even when our eyes are closed, all living things are like this.  It has been suggested that this has developed from an evolutionary process as a self defense/protective mechanism, allowing living things to be aware (partially) even when we are at our most vulnerable i.e. asleep.

Answer 3

It is a survival instinct reaction, from when we were hunters and protectors, sleep at night, up with the sun.