This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S., Subject name: Medicine
[{'content': 'What is the diagnosis in this patient who presented with sudden painful vision impairment after vigorous exercise? \nSelect and explain. \nA. Central retinal artery occlusion, B. Corneal ulcer, C. Dislocation of the lens, D. Episcleritis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Answer C. Dislocation of the lensThere is anterior dislocation of the lens. Rupture of the zonular fibers may result from ocular trauma or other conditions. The patient underwent surgical extraction of the dislocated lens, anterior vitrectomy, and implantation of an iris-fixated intraocular lens.', 'role': 'assistant'}]