Vitamin is a necessary substance for human metabolism, but the need is not large, the normal daily diet is enough to maintain the body’s needs, if some causes of vitamin deficiency can lead to systemic and eye diseases occur. 1, vitamin A deficiency The normal human body needs 5000 ~ 7000Iu / day; below 20Iu / L (in the blood) caused by vitamin A deficiency, can cause night blindness, dry eye and corneal softening disease. 2, vitamin B1 deficiency The normal human body needs 1 mg / daily, the plasma vitamin B1 content is reduced (below 20μg / L) can appear eye lesions, such as conjunctival corneal epithelial damage, dry eye, retrobulbar optic neuritis, optic nerve atrophy, oculomotor nerve palsy, etc. 3, vitamin B2 and vitamin PP deficiency, including riboflavin and niacin, the human body needs 12 to 15 mg per day. Niacin deficiency can cause optic neuritis and retinitis. Riboflavin (VitB2) deficiency can cause conjunctivitis, blepharitis, rosacea keratitis, neovascularization around the corneal edge and cataract. 4, vitamin C deficiency human needs 50-100 mg / day, plasma content of 6.32μg / L; lack of vitamin C can cause eyelid, conjunctiva, anterior chamber, vitreous, retina and orbital hemorrhage, cataract occurrence, corneal epithelial growth is affected, etc.. 5, vitamin D deficiency Mainly abnormal bone development in childhood causes orbital hypoplasia narrowing, eye protrusion, eyelid spasm, refractive error, low calcium cataract, etc.