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
Atropine is substituted by phenylephrine to facilitate fundus examination when? 
Select and explain. 
A. Mydriasis required without cycloplagia, B. Cycloplegia is required, C. Mydriasis and cycloplegia both required, D. Cycloplegia and mydriasis both are not required
A: Mydriasis required without cycloplagia
Answer: A: Mydriasis required without cycloplagia 
Explanation: Ans. is 'a' i.e., Mydriasis required without cycloplagia o Anticholinergic drugs (atropine) cause i) Mydriasis ii) Paralysis of ciliary muscles (cycloplegia) o Adrenergic drugs (phenylephrine) cause i) Mydriasis ii) Has no action on ciliary smooth muscles --> no cycloplegia For fundoscopy only mydriasis is required (no cycloplegia is required) --> Phenylephrine is preferred over atropine.