The most likely cause (99%) is outflow obstruction, while less likely are over-secretion and otion. An obvious test is the sodium fluorescein dye disappearance (FDD) rate, in which fluorescein is instilled into the anterior eye and the drainage of the stained tears via the puncta is assessed. As no probing or syringing is undertaken it is regarded as a passive test, but it is also less sensitive than other methods.{{quote-A:R-W:480-Q:Generally, a watery eye without irritation is likely to be a case of an outflow obstruction.}}A comparison of drainage rates between eyes can also be useful; an active method is probing (with a Bowman’s probe) and syringing (P&S), in which tactile feedback during either procedure can indicate drainage syst restrictions or obstructions. Constancy of syringe and cannula size (19 gauge) was recommended and syringing obviated the need to use probing. The use of normal saline was suggested and its salty taste can confirm some patency of the syst.Any need to dilate the puncta or the canaliculi is suggestive of a probl, and any blockage or significant stenosis will result in rapid regurgitation of injected saline. Generally, a watery eye without irritation is likely to be a case of an outflow obstruction.A sophisticated approach to an investigation of epiphora is to use scintigraphy – ploying radioisotope labelling of the injected liquid and mapping the itted gamma radiation over time (a 20 min test) to disclose the liquid’s flow and destination(s). Currently, Sydney’s Royal Prince Alfred (RPA) and Concord Hospitals have such nuclear medicine facilities.Possible blockage locations that are often associated with irritation or discharge are at the lid, the common canaliculus (CC) or the naso-lacrimal duct (NLD), while there is normally no discharge at other blockage sites such as the puncta and the canaliculi.Ghabrial uses a point scoring syst to differentiate lacrimation from epiphora, but it is scored as epiphora automatically if a mucocoele, dacryocystitis, or a P&S block are detected. Treatment can be by a dacryocystorhinostomy (DCR), which has a 90% success rate, or a recanalisation, which is typically successful 60% of the time.Modern DCR is usually a day-surgery procedure using sedation and can be done by an oculoplastics surgeon or an ENT specialist. If the blockage is in the canaliculus, a DCR using a Jones tube usually results in 80% patient satisfaction.
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Clinical Associate Professor RAF GHABRIAL is an ophthalmologist practising in the oculoplastics sub-specialty on Sydney’s Macquarie St. He has written numerous chapters for texts and scientific publications in medical literature, and is regularly invited to facilitate lectures and surgical courses both nationally and internationally. |
