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: Pharmacology
Most important side effect of ethambutol is : 
Select and explain. 
A. Hepatotoxicity, B. Renal toxicity, C. Peripheral neuropathy, D. Retrobulbar neuritis
D: Retrobulbar neuritis
Answer: D: Retrobulbar neuritis 
Explanation: None