This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
[{'content': 'A Middle aged man brought to casualty with unilateral headache, right eye congested and painful, with sudden vision loss. The diagnosis is \nSelect and explain. \nA. Angle Closure Glaucoma, B. Corneal edema, C. CRVO, D. CRAO', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Angle Closure Glaucoma# Angle-closure glaucoma, also known as narrow-angle glaucoma, is caused by blocked drainage canals in the eye, resulting in a sudden rise in intraocular pressure.> This is a much more rare form of glaucoma, which develops very quickly and demands immediate medical attention. Symptoms of angle-closure glaucoma may include:> Hazy or blurred vision: The appearance of rainbow-colored circles around bright lights Severe eye and head pain Nausea or vomiting (accompanying severe eye pain) Sudden sight loss', 'role': 'assistant'}]