What is the vitamin in carrots that is supposed to help your eye sight?

Beta Carotene. Vitamin a and more importantly, its derivatives, are found in abundance in the retina (the film layer of the eye). It is very important for the proper functioning of the eye. What is not very clear is whether eating a lot of foods rich in vitamin a makes any difference in the overall health of the eye, as long as you are not deficient in it.