This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro-ophthalmology, Subject name: Ophthalmology
The earliest sign of papilledema is 
Select and explain. 
A. Less pulsations, B. Blurring of disc margin, C. Obliteration of cup, D. Cotton wool spots
B: Blurring of disc margin
Answer: B: Blurring of disc margin 
Explanation: Early (incipient) papilloedema:_ Symptoms are usually absent and visual acuity is normal._ Pupillary reactions are normal.Ophthalmoscopic features of early papilloedema are: (i) Obscuration of the disc margins (nasal margins are involved first followed by the superior, inferior and temporal) (ii) Blurring of peripapillary nerve fiber layer. (iii) The absence of spontaneous venous pulsation at the disc(appreciated in 80% of the normal individuals).(iv) Mild hyperemia of the disc. (v) Splinter hemorrhages in the peripapillary region may be present._ Visual fields are fairly normal.Ref: Khurana; 4th edition; Pg.No. 299