Conjunctival xerosis (conjunctival dryness) is a phenomenon of conjunctival dryness that occurs mainly as a result of lesions in the conjunctival tissue itself, and has a variety of causes. Under normal conditions, the tear fluid secreted by the lacrimal gland and conjunctival cup cells keeps the conjunctiva constantly moist, but once the above moisturizing function is disrupted, conjunctival xerosis occurs. Conjunctival dryness can be divided into epithelial conjunctival dryness and substantial conjunctival dryness. Clinically, cod liver oil drops are used, along with antibiotic solutions and ointments to prevent and treat secondary infections, corneal ulcers and corneal softening. The syndrome is an ocular manifestation of systemic nutritional disorders and vitamin A deficiency. The causes are as follows: 1, insufficient intake, such as improper pediatric feeding. Or because of the disease “taboo” caused by insufficient intake. 2, malabsorption, such as indigestion, gastroenteritis, dysentery, etc. can affect the absorption of vitamin A, and vitamin A deficiency can be caused by intestinal epithelial lesions, so the formation of a vicious circle. 3, excessive consumption of young children’s period of rapid physical growth and development, the need for vitamin A is greater. When suffering from measles, pneumonia, whooping cough and other diseases when the consumption of vitamin A increased. 4, adult vitamin A deficiency is occasionally seen in long-term serious gastrointestinal digestive diseases, vitamin A malabsorption, liver and lung diseases: such as liver cirrhosis, advanced liver cancer, due to severe damage to liver function, resulting in fat absorption caused by fat-soluble vitamin A deficiency.