Eyes structure Fact

Each eye contains 130 million cells, all of which are sensitive to light.
However, cells that respond to color and light take up only a small
area in the central part of the retina. The very same square
the retina corresponds to the size of the back of the eyeball.
Let me remind you that the cells of the retina tissue are similar in structure to
neurons of the brain. It is not a coincidence that peoples says that the eyes are the brain,
brought out.
From this fact alone, it is clear that retina is so difficult,
how can eyes operations be possible,
replacement with any materials, devices or
donor organs?