I was watching an interesting show on cable a few nights ago about the human eye.
and why some people are colour blind and some are not.

Like the sensors in our camera, the retina is populated by "sensors" that are sensitive to one of 3 colours, and colourblind people are generally only sensitive to 2 colours.
Some scientist has now worked out how to replace the missing colour on a retina to give the patient full colour vision.
He hasn't operated on humans as yet, but his work with monkeys has been very successful, so hopefully, soon there will be a cure for colour-blindness.
It seems that the males of a particular monkey species are colour-blind, whereas the females are not and it has been discovered that the male monkeys cannot see the colour red so he has worked out a way of introducing these red receptors into the eye to give full colour vision.
The tests I saw on TV showed that male monkeys had full colour vision after the operation where they did not have it beforehand.

Another interesting thing was how many receptors each of our eyes have, and it seems that our eyes have around 100 milion sensors per eye.
That's 200million pixels in total, so our cameras still have a way to go to match the definition our eyes have.