This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lacrimal Apparatus and Eyelid Disorders, Subject name: Ophthalmology
[{'content': 'What is the anatomical relation of the upper lacrimal punctum with respect to the lower punctum? \nSelect and explain. \nA. Medial, B. Lateral, C. Apposed, D. No relation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The lacrimal puncta are located medially on the upper and lower eyelids, on the lacrimal papilla and the upper punctum is medial to the lower punctum. The puncta are apposed only during the closure phase of blinking, Normally.The PAS (punctual apposition syndrome) represents the situation in which at any stage during the blinking cycle, other than when the puncta actively appose during the closure phase of blinking, the puncta are apposed and the patient experiences watering', 'role': 'assistant'}]