This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
What is the diagnosis of the following examination of the fundus? 
Select and explain. 
A. Diabetes retinopathy, B. Optic atrophy, C. Acute glaucoma, D. Optic disc drusen
C: Acute glaucoma
Answer: C: Acute glaucoma 
Explanation: Glaucoma results in "cupping" as the neural rim is destroyed and the central cup becomes enlarged and excavated. The cup-to-disc ratio is about 0.7/1.0 in this patient.