This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glaucoma, Subject name: Ophthalmology
Which of the following is not a disc sign in glaucoma? 
Select and explain. 
A. Bayonetting, B. Nasalization of vessels, C. Disc edema, D. Large cup
C: Disc edema
Answer: C: Disc edema 
Explanation: Disc edema is not a sign of glaucoma. Optic nerve head changes seen in glaucoma Thinning of neuroretinal rim Large cup Nasalisation of vessels Deep cup Asymmetry of cup Disc hemorrhage Baring of blood vessels Bayonetting sign Laminar dot sign Pulsations of disc seen in very high IOP