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': 'In papilledema, all the following are true except - \nSelect and explain. \nA. Blurring of the disc, B. Congestion of retinal veins, C. Soft white exudates around the disc, D. Sudden loss of vision', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Visual acuity and pupillary reactions usually remain fairly normal until late stages when optic atrophy sets. Even then, there is gradually progressive painless loss of vision.', 'role': 'assistant'}]