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
A patient of glaucoma with bronchial asthma presents to the emergency with status asthmaticus, causative agent might have been – 
Select and explain. 
A. Pilocarpine eye drop, B. Timolol eye drop, C. Betaxolol eye drop, D. Levobunolol eye drop
B: Timolol eye drop
Answer: B: Timolol eye drop 
Explanation: Pilocarpine and timolol (β - blockers) can cause bronchospasm. However, β-blockers are the most commonly used drugs for POAG and pilocarpine is used very rarely these days. So, best answer here is timolol.