Control of lacrimal secretion after sphenopalatine ganglion block.

Tear secretion with topical anesthesia ("Basal secretion") was measured in 10 normal subjects using Schirmer's tear strips before and after a sphenopalatine ganglion block. In an additional three normal subjects, tear turnover was determined with an objective fluorophotometer both before and after sphenopalatine ganglion block. The sphenopalatine ganglion block was obtained by the injection of the lidocaine (2%) into the sphenopalatine fossa. Topical anesthesia (proparacaine 0.5%) was used prior to all measurements. Tear secretion with topical ocular anesthesia was reduced substantially by sphenopalatine block, as measured by either Schirmer's strips or objective fluorophotometry. The more exact fluorophotometric method recorded a complete cessation of tear turnover flow following ganglion block. These findings support other reports, suggesting that all tear secretion is under neurologic control and dependent on reflex stimulation.