This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': 'Xerophthalmia is caused by -a) Vit C deficiencyb) Small bowel resectionc) Cystic fibrosisd) Chronic alcoholisme) Glomerulonephritis \nSelect and explain. \nA. abc, B. acd, C. bcd, D. bd', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Xerophthalmia \n\nThe term xerophthalmia is now reserved (by a joint WHO and USAID Committee, 1976) to cover all ocular manifestations of vitamin A deficiency, including not only the structral changes affecting the conjunctiva, cornea and occasionally retina, but also the biophysical disorders of retinal rods and cones functions.\nIt occurs either due to dietary deficiency of vitamin A or its defective absorption from the gut. It has long been recognized that vitamin A deficiency does not occur as an isolated problem but is almost invariably accompained by protein-energy malnutrition (PEM) and infections.\n\nImportant causes of xerophthahmia (VitA deficiency)\n\nFat malabsorption due to any case (e.g. small bowel resection, cystic fibrosis\nInfection → measles\nDiarrhoea\nMalnutrition due to any cause :- chronic alcoholism\nPEM', 'role': 'assistant'}]