The first category is foods containing more vitamin A, such as beef liver, sheep liver, pig liver, chicken liver, egg yolk, butter, milk and goat milk. Keep the cornea normal and don't make it dry and degenerate. Enhance the ability to see in the dark.

The second category is foods containing more carotene, such as carrots, pumpkins, green beans and tomatoes. It's best to cook it in oil, or add some cooked oil when it's cold. This carrot can transform vitamin A in human body.

The third category is foods containing more riboflavin (vitamin B2), such as milk, bean jelly, lean meat, eggs, yeast and lentils. It can ensure the normal metabolism of retina and cornea of eyes.