There are several ways we can know what a dog, a bird or, indeed, any other organism can see, for example either by looking at the structure of the eye and comparing it with other species, or by behavioural tests.
If you go to the octopus, and if you're not too squeamish, dissect it. You'll find that it has a camera eye which is remarkable similar to our own. And yet we know that the octopus belongs to an invertebrate group called cephalopod mulluses, evolutionarily very distant indeed from the chordates to which we belong.
Although Darwin was able to persuade much of the world that a modern eye could be produced gradually from a much simpler structure, he did not even attempt to explain how the simple light sensitive spot that was his starting point actually worked.
How many human eyes...had snatched glimpses of their secret anatomies, down the passage of years?
The human eyelid is not teartight (happily for the human eye).
If you look at how beautiful the eye can be, it has its own inside patterns and colors.
the small tuft of fronds or katydid legs above each eye, still numbering the units in each group; the shadbones regularly set about the mouth, to droop or rise
Kim Kardashian and Kris Jenner have the exact same eyes.
