Most vertebrates have eyelids or some other means of protecting their eyes from strong sunlight, which would otherwise cause irreversible damage. Insects, and many other invertebrates, on the other hand, habitually sit or cruise around with their eyes, or parts of them, pointing upwards towards full sunlight, with no apparent adverse effects. Why does direct sunlight not damage their eyes?

As a supplementary, would photographic flash light damage the eyes of an invertebrate?

Do we all perceive color the same way ? for example do we all see the same color green or is the word green or red or blue just names to tag how we perceive those color. If I switched eyes with someone he might see the grass the same way as I perceive the sky but still call it green even though for me it would be blue.

The same goes for colorblind people (those unfortunate to mix up colors) if they were brought up seeing the grass as we would see it red. He would say green to everything red if we were able to see through his eyes. It would rely on education then.

Do I make sense ?

Last week, I helped a blind guy cross the road and while we were crossing the road I asked him if blind people can hallucinate and have dreams. He said "Of course we can". I researched this and it turns out that blind people can in fact hallucinate.

This got me thinking. I was wondering if it is possible that we are all blind and we are all hallucinating the same things?