This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and Errors of Refraction, Subject name: Ophthalmology
[{'content': 'Jaegers cha is used to measure \nSelect and explain. \nA. Distant vision, B. Near vision, C. Color vision, D. Contrast sensitivity', 'role': 'user'}, {'content': "Answer: B \nExplanation: Jaeger's cha is used for measuring Near Vision The Jaeger cha is an eye cha used in testing near vision acuity. It is a card on which paragraphs of text are printed, with the text sizes increasing from 0.37mm to 2.5mm. This card is to be held by a patient at a fixed distance from the eye dependent on the J size being read. The smallest print that the patient can read determines their visual acuity", 'role': 'assistant'}]