Assessment of lacrimal resistance using a manometric tear duct irrigation system

ABSTRACT

Lacrimal surgery aims to provide a low-resistance tear drainage passage. An assessment of lacrimal resistance guides decisions on surgery. We present results of a modified tear duct irrigation system that reliably measures lacrimal outflow resistance. Patients in a specialist lacrimal clinic had a full work-up to the point of tear duct syringing. The tear ducts were irrigated using a manometric system, which applied a fixed, known head of fluid pressure to a lacrimal cannula. Fluid flow is recorded and the lacrimal resistance derived as fluid pressure/fluid flow (units cmH20 secml-1, for simplicity presented as drops per minute, dpm). Patient groups were: A: Asymptomatic, A1: subgroup where the fellow symptomatic eye had a visible cause for watering, B: external visible cause for watering (ocular surface/lid/punctum), C: no externally visible cause, D: post op DCR, E: post syringing and probing, F: mixed/other. 444 tear ducts were examined. Mean flows (dpm) were: A1 (n = 19) 55; B (n = 183) 46; C (n = 142) 22: D (n = 38) 52. Excluding complete obstruction (n = 29), tear duct syringing only detected 48% of those with impaired manometric flow. Of those with a normal tear duct syringing, 53% had impaired manometric flow; 34% had a flow of 0 dpm. Differences in A1 versus C; B versus C and pre versus post dacryocystorhinostomy were all statistically significant (p < 0.05). The manometric system presented reliably measures lacrimal resistance and provides a substantial increase in sensitivity and specificity over conventional lacrimal syringing.

KEYWORDS:

• Dacryocystorhinostomy
• epiphora
• lacrimal outflow
• lacrimal syringing
• manometric

Acknowledgments

Mr Rafal Artur, Department of Ophthalmology, Royal Berkshire Hospitals NHS Foundation trust, Craven Road, Reading, RG1 5AN, UK.

Disclosure statement

All authors have no proprietary or financial interests to declare and no research funding was received.