Schirmer's test detects abnormality of which nerve?
High-Yield Explanation
(Refer: AK Khurana Comprehensive Ophthalmology, 6th edition, pg no. 389)*Schirmer's test is used for the production of tear by lacrimal glands*Preganglion secretory fibers for lacrimal gland arise from the lacrimatory nucleus and pass through the facial nerve, then to its greater petrosal branch. Greater petrosal nerve forms nerve to the pterygoid canal to reach pterygopalatine ganglion. Postganglionic fibers supply lacrimal gland*Thus, lesion in any structure of this pathway will have positive Schirmer's test