This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Investigation in ophthalmology and miscellaneous topics, Subject name: Ophthalmology
[{'content': "Normal value of Schirmer's test should be at least: \nSelect and explain. \nA. 15 mm, B. 45 mm, C. 60 mm, D. 30 mm", 'role': 'user'}, {'content': "Answer: A \nExplanation: Schirmer's test- It measure total tear secretions. It is performed with the help of a 5*35mm strip of whatman-41 filter paper which is folded 5mm from one end and kept in the lower fornix at the junction of lateral one third and medial two third. The patient is asked to look up and not to blink or close the eyes. After 5 minutes wetting of filter paper strip from the bent end is measured. Normal values of schimer test are more than 15mm values of 5-10mm are suggestive of moderate to mild keratoconjuctivitis sicca Less than 5mm are suggestive of severe keratoconjuctivitis.", 'role': 'assistant'}]