Vitamin A is a good essential vitamin for eye care and is more beneficial for people with chronic eye use or dry eyes. There are not many cases of obvious vitamin A deficiency in normal diet and life state, but the body is often deficient in the following states 1. Inadequate intake, such as improper feeding of children. Or insufficient intake due to “taboo” when sick. 2, malabsorption, such as indigestion, gastroenteritis, dysentery, etc. can affect the absorption of vitamin A, and the lack of vitamin A can cause the epithelial lesions of the intestinal wall, thus forming a vicious circle. 3, too much consumption The body grows faster during early childhood, and the need for vitamin A is greater. When suffering from measles, pneumonia, whooping cough and other diseases, the consumption of vitamin A increases. 4, adult vitamin A deficiency Occasionally seen in long-term suffering from serious gastrointestinal digestive diseases, liver and lung diseases: such as liver steatosis, advanced liver cancer, due to serious damage to liver function, resulting in fat malabsorption and fat-soluble vitamin A deficiency. Of course, when there is too much eye use, such as copywriters or people who frequently use computers, the need for vitamin A will be even greater, which may cause relative vitamin A deficiency despite a normal diet. Vitamin A is the main nutrient to maintain the normal metabolism of human epithelial tissues, to maintain the normal cornea, not to make the cornea dry and degenerate, and has the effect of enhancing the ability to see in the dark light. If the body is deficient in vitamin A, in addition to dry eye, keratitis, dry eye disease, photophobia, tearing, and can even lead to thickening or softening of the conjunctiva, vision loss, resulting in night blindness or insomnia. Therefore, it is important to use foods rich in vitamin A in your diet. The Chinese Nutrition Society recommends a daily intake of 800 international units of vitamin A for men and 700 international units for women, but data from the National Nutrition Survey shows that the lack of vitamin A intake in China is mainly related to the structure of the diet, but also to partial and picky eating. Vitamin A is mainly contained in animal foods such as animal liver, eggs, milk, cod liver oil, butter and other foods. In addition, carotene is a prerequisite substance for vitamin A. It can be converted into vitamin A in the body, but its conversion rate is only 1/6, mainly contained in carrots, spinach, lettuce leaves, leeks, hollow cabbage (bamboo leaf vegetable), pea seedlings, alfalfa, pumpkin, tomatoes, amaranth, loquat, purple cabbage, green beans, etc.