ABSTRACT Using the Olympus PF-22 angioscope to examine the inferior meatus during secondary dye testing of the lacrimal system, I evaluated the efficacy of the secondary dye test to localize partial or functional obstruction of the upper or lower lacrimal excretory system. Secondary dye testing was positive (dye present in the nose) in 12 of 13 lacrimal systems (92%) with functional nasolacrimal duct obstruction, in 7 of 8 (89%) with involutional ectropion, and in 4 of 5 (80%) with facial nerve palsy. Secondary dye testing was negative in the 1 lacrimal system w'rth canalicular stenosis and in 5 of the 6 (83%) with punctal stenosis. Secondary dye testing is helpful in differentiating punctal or canalicular stenosis from functional nasolacrimal duct obstruction; however, it cannot help differentiate ectropion or facial nerve palsy from functional nasolacrimal duct obstruction.