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
Cause of blindness in CRVO 
Select and explain. 
A. Cystoid macular edema, B. Macular hemorrhage, C. Vitreous hemorrhage, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: All are causes of blindness in CRVO but most important is CME.