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': "Fincham\\'s test differentiates cataract from – \nSelect and explain. \nA. Conjunctivitis, B. Iridocyclitis, C. Open angle Glaucoma, D. Ac. Congestive Glaucoma", 'role': 'user'}, {'content': "Answer: D \nExplanation: The coloured halos in primary angle closure glaucoma must be differentiated from those found in acute purulent conjunctivitis and early cataractous changes :-\n\n\nIn conjunctivitis, the halos can be eliminated by irrigating the discharge.\nThe halos of glaucoma and immature cataract may be differentiated by Fincham's test in which a stenopaeic slit is passed across the pupil. During this test glaucomatous halo remains intact, while a halo due to cataract is broken up into segments.", 'role': 'assistant'}]