A simple diagnostic test has been developed for the evaluation of the patency of the lacrimal excretory system. A 1% saccharin solution was instilled in the conjunctival cul-de-sac and then tasted by the patient when it reached the oropharynx; this painless and effective test was performed in a study using 100 subjects. The average time lapse between instillation and tasting was 3 ½ minutes. Hopefully, this sweetness-tasting test will be used to identify lacrimal obstruction problems. The test is physiological and reliable. It has proved clinically useful in diagnosing epiphora.
Hornblass A. A Simple Taste Test for Lacrimal Obstruction. Arch Ophthalmol. 1973;90(6):435-436. doi:10.1001/archopht.1973.01000050435003