Walsh & Hoyt: Regulation of Tear Secretion

Jones hypothesized that tear secretion could be clinically separated into two types: basal secretion, which originated from the accessory lacrimal glands and occurred independent of stimulation, and reflex secretion, which originated from the main lacrimal gland and occurred only in response to neural stimulation. He believed that the tears that were produced after administration of topical anesthesia were caused by basal secretion. Regardless of the clinical advantages of this classification, this study may have led to the false impression that the role of the nervous system in the regulation of tear production is limited to parasympathetic neural stimulation of the main lacrimal gland. Proof that even basal tear production is neurologically regulated is that basal tearing is essentially eliminated in humans by the injection of lidocaine anesthetic into the sphenopalatine ganglion.