“Blue eyes” refers to the light blue color of the sclera of the eye at normal natural light levels. In medical terms, this is known as blue sclera. This bluish sclera is an early sign of iron deficiency anemia. Due to insufficient oxygen supply, the blood in the body flows more to the vital organs, while the blood vessels of those organs that are temporarily less affected, such as the skin and mucous membranes, begin to constrict. As a result, there is often a whitening of the skin, mucous membranes inside the eyelids, etc., and a blue sclera appears. The human sclera is composed of collagen tissue, and iron in the body is an important cofactor in the synthesis of collagen. If the body is deficient in iron, the collagen synthesis is insufficient and the sclera becomes thin and cannot effectively cover the brownish-black choroid in the eye, which appears light blue in natural light. Some studies have shown that the sclera of Asian children should be grayish white and if it is blue, it can be considered as anemia. This is because the pale skin and mucous membranes that should be present in children with anemia often appear later than the blue sclera. In addition, genetic blue sclera is relatively rare. It usually refers to an increase in scleral transparency and thinning, with uveal pigment visible through the sclera. Blue sclera is a congenital autosomal dominant inheritance. Warm tips: pay attention to giving iron supplement in the diet. It is extremely important to actively psychologically induce, change and expand recipes, and promptly correct the paranoid and picky eating common in these children.