You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Atropine is substituted by phenylephrine to facilitate fundus examination when? and explain in detail?
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.