I don't know how vitamin A improves eyesight, but lack of vitamin A is the main cause (70%) of childhood blindness throughout the world, with 500,000 going blind every year due to lack of vitamin A. The amount of vitamin A required to prevent blindness is small.
None, really.
Vitamin A is chemically related to a pigment involved in eyesight, and is used in the body to make that pigment, but it's not so much "vitamin A makes your eyes work better" as "vitamin A keeps your eyes from not working at all."
If your diet is so deficient in vitamin A that your eyesight is failing because of it (note: we're talking actual night blindness here, not "I have trouble seeing tiny things a long way away"), taking vitamin A could result in some improvement. If your eyesight is more or less normal with respect to night vision, then vitamin A is not going to make it "better."
In particular, vitamin A has nothing to do with whether you need glasses or not. That's a purely physical matter having to do with the lens, and vitamin A is involved in the biochemistry of the retina.
vitamin b, c, d , and e
Vitamin A - betacarotene - is best for our eyes
Vitamin A can improve your eyesite.
E
vitamin A
Vitamin A
Vitamin A is essential for eyesight.
Vitamin A.
Carrots contain a substance called carotene which when digested produces vitamin A, which is essential for good eyesight.
Vitamin A is needed for good eyesight.
Vitamin A
Vitamin K is primarily good for the blood. It helps prevent blood clots as well as strengthen bones. It is good for the circulatory and nervous systems in the body. Vitamin A is primarily good for eyesight and immune functions.
It does contain vitamin A which is good for eyesight
vitamin c
it is good
eyesight
yes but they do not improve eyesight they maintain it. carrots have lots of vitamin A, you can tell if you are low in vitamin A by having low night vision.
Vitamin K