Answer :

AL2006
I think you must be referring to the fact that our eyes invert the image, so that
the image on the retina is upside-down, and that worries you.

The answer is:  It's all easily handled by that glob of gray stuff inside our head.
The brain takes the inverted image, and responds to it as if it were right-side-up.

That sounds complicated and difficult, because we have no idea how terrific
our brain really is.  So let me tell you this story, and it'll blow your mind:

When psychologists realized that the brain was turning everything we see
right-side-up, they did an experiment.  They had some special glasses made,
that would turn everything upside-down before it went into the eyes, so that
the image on the retina would be right-side-up, and the person would see
everything upside-down.  Then they had some people try to go through their
normal activities with these glasses on.  Want to know what happened ?
The test subjects were pretty awkward at first, tripping over things and
bumping into walls.  But after a few days, their brain made the adjustment,
and they didn't notice anything strange any more. They could read books,
wash the dishes, play ball, and most of them were even able to ride bicycles
around their neighborhood in the normal way !  Then, when the experiment
was over, they took the glasses off, and they were awkward again for a few
days, and then their brains flipped everything over again and they got
re-adjusted to normal.

THAT's how clever our brain is !