X2-Corneal xerosis X3A-Corneal ulceration/keratomalacia, involving less than one-third of the cornea X3B-Corneal ulceration/keratomalacia, involving more than one-third of the cornea XS-Corneal scar due to xerophthalmia XF-Xerophthalmic fundus Prevention Prophylaxis consists of periodic administration of Vitamin A supplements. WHO recommended schedule, which is universally recommended is as follows: Infants 6–12 months old and any older children weighing less than 8 kg – 100,000 IU orally every 3–6 months Children over 1 year and under 6 years of age – 200,000 IU orally every 6 months Infants less than 6 months old, who are not being breastfed – 50,000 IU orally should be given before they attain the age of 6 months Treatment Treatment can occur in two ways: treating symptoms and treating the deficiency. Treatment of symptoms usually includes the use of artificial tears in the form of eye drops, increasing the humidity of the environment with humidifiers, and wearing wraparound glasses when outdoors. Treatment of the deficiency can be accomplished with a Vitamin A or multivitamin supplement or by eating foods rich in Vitamin A. Treatment with supplements and/or diet can be successful until the disease progresses as far as corneal ulceration, at which point only an extreme surgery can offer a chance of returning sight. Epidemiology Throughout southeast Asia, estimates are that more than half of children under the age of six years have subclinical vitamin A deficiency and night blindness, with progression to xerophthalmia being the leading cause of preventable childhood blindness. Estimates are that each year there are 350,000 cases of childhood blindness due to vitamin A deficiency. The causes are vitamin A deficiency during pregnancy, followed by low transfer of vitamin A during lactation and infant/child diets low in vitamin A or beta-carotene. The prevalence of pre-school age children who are blind due to vitamin A deficiency is lower than expected from incidence of new cases only because childhood vitamin A deficiency significantly increases all-cause mortality. See also Keratoconjunctivitis Keratoconjunctivitis sicca Keratomalacia, also caused by vitamin A deficiency. References Further reading Jellife DB. "Xerophthalmia: A World-wide Drive for Prevention." Journal of Tropical Pediatrics 1980; 26: ii-iii. 4 November 2009. External links Disorders of eyelid, lacrimal system and orbit Vitamin deficiencies