The authors assessed the lacrimal outflow resistance with a modified irrigation system. The manometric tear duct test (mTDT) comprised of a 6mm thin wall 25 gauge lacrimal cannula which was attached to a bag of normal saline by standard fluid administration tubing. In total, 444 tear ducts were examined using mTDT. Patients had a full work-up to the point of tear duct syringing. It is uncertain whether both syringing and manometric assessment were done with patients in sitting position or lying down. The mTDT results were divided into six groups A: asymptomatic, A1: subgroup where fellow symptomatic eye had a visible cause of watering, B: external visible cause of watering (ocular surface/lid/punctum), C: no external visible cause, D: postop dacrocystorhinostomy (DCR), E: post syringing and probing, F: mixed / other. Excluding complete obstruction (n=29), tear duct syringing only detected 48% of those with impaired manometric flow. Of those with normal tear duct syringing, 53% had impaired manometric flow; 34% had a flow of zero (drops per minute. The authors found mTDT a more sensitive and reliable method compared to conventional syringing in identifying patients with epiphora related to high resistance in a non-obstructed nasolacrimal duct system and when there is no visible cause for watering. Authors conclude that manometric technique is well tolerated, is better at assessing the lacrimal resistance, is objective and clinically consistent. The authors acknowledge the limitation of the need for two people to perform the test. This indeed would have resource implications of additional time for assessment as well as cost of the manometric system.