The effects of nasolacrimal canal blockage on topical medications for glaucoma.

Twenty patients with primary open angle glaucoma who have been treated with identical antiglaucoma eye drops in both eyes were examined. Silicone punctal plugs were used to occlude the inferior punctum of one eye, in order to block the nasolacrimal canal. The intraocular pressures and effects of the medical therapy before and after punctal occlusion were compared. Punctal occlusion significantly decreased the intraocular pressure with an average of 2.00 +/- 0.43 mmHg in the plugged eyes (p < 0.001). The intraocular pressure in the unplugged control eyes did not change significantly (p > 0.05) after punctal occlusion of the fellow treated eye.