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
Papilloedema is characterised by all of the following EXCEPT- 
Select and explain. 
A. Loss of retinal venous pulsations, B. Transient obscurations of vision, C. Sudden painless loss of vision, D. Disc oedema
C: Sudden painless loss of vision
Answer: C: Sudden painless loss of vision 
Explanation: Vision loss occurs in long standing papilloedema (not in acute pappiloedema), and that occurs in less than 25% of patients.
Post neuritic atrophy also occurs in long standing papilloedema and not acute papilloedema.