Be careful with Vitamin A -- too much is bad for the liver. Better to take it in the form of betacarotine, which will only give as much A as you need and flush the rest. But A isn't the main nutrient for the eye, it's one of many. Again, the eye requires many nutrients. It requires essential fats, it requires colored veggies, especially dark green ones for lutein, the main carotenoid for the eye, it requires just a ton of nutrients.