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
Hutchinson's rule in relation to herpes zoster ophthalmicus: 
Select and explain. 
A. Implies that ocular involvement is infrequent if the side or tip of the nose presents vesicles, B. Is based on involvement of nasociliary nerve, C. Is 100 percent predictor of ocular involvement, D. All of the above
B: Is based on involvement of nasociliary nerve
Answer: B: Is based on involvement of nasociliary nerve 
Explanation: Ans. Is based on involvement of nasociliary nerve