Introduction
Lacrimal syringing is performed to:
(a) assess the patency of the lacrimal system
(b) flush debris from the system – which can improve epiphora symptoms
(c) elucidate the level of blockage where the system is found to be non-patent
Before performing any eye procedure
Wash your hands (and afterward too).
Position the patient comfortably with the head supported.
Minimize distractions, both for yourself and the patient.
Ensure good lighting.
Always explain to the patient (and any companion, if appropriate) what you are going to do.
Equipment
Equipment to be assembled:
- a torch (held by an assistant) or preferably a well-powered lamp
- magnification (e.g., loupes) - not essential but helpful
- normal saline
- a sterile 2 ml syringe
- a sterile Nettleship dilator
- a sterile lacrimal cannula
- local anesthetic eye drops
- clean cotton wool or gauze swabs
- gloves
Preparation
Position the adult patient lying down with head supported on a pillow, or sitting with the head against the high back of a chair.
If the patient is a child, you may need to ask your assistant to wrap the child in a sheet and gently restrain the child throughout the procedure.
Place the towel across the patient's neck to absorb any fluid spillage.
Check the Nettleship dilator and do not use it if there is any damage to the tip.
With the syringe, draw up about 1 ml of saline and then attach it to the cannula.
Flush the cannula with a small amount of saline to ensure it is patent.
Method
Explain the procedure to the patient and gain consent
Wash your hands
Put on gloves
Position the patient comfortably with head supported – either lying on exam bed at 45 degrees or reclined in an examination chair
Ensure good lighting with a torch or preferably an overhead lamp.
Place a towel across the patient’s neck to absorb any fluid spillage.
Prepare equipment - that is, check your Nettleship dilator to ensure the tip is not damaged; prepare flush by drawing up 2 ml of saline into a syringe and attaching cannula.
Instill local anesthetic eye drops into eyes and directly over punctum - wait about 30 seconds.
Ask the patient to look upwards and outwards (away from the nose) and to maintain this gaze until the procedure is over.
With a gauze swab gently pull down the lower eyelid to expose the lower punctum.
On the other hand, insert the Nettleship dilator into the lower punctum, following the direction of the lower canaliculus - that is vertically downward for the first 2mm. Gently rotate the dilator between the fingers clockwise/anticlockwise as it is inserted.
After the first 2mm of vertical insertion, and with the dilator still in situ, apply slight lateral traction on the lower lid to straighten the ampulla of the lower canaliculus and then continue to gently insert the dilator but in a more horizontal direction nasally to continue following the direction of the canaliculus (this dilation will facilitate the insertion of the cannula).
Take the syringe with the attached cannula and insert the tip of the cannula in the lower punctum.
Again, apply slight lateral traction to the lower lid as the cannula is inserted along the canaliculus.
Insert the cannula until a "stop" is reached - and determine whether the stop is soft (spongy) or hard (bony)
Withdraw the cannula 2mm from the stop point and slowly inject fluid
Explain to the patient that they may have the sensation of a salty taste at the back of the mouth and to notify you when this occurs
Assess the ease/resistance of the fluid flush and look at the upper punctum to assess for regurgitation
If the patient is not aware of a salty fluid sensation in the throat, it indicates a blockage somewhere in the lacrimal apparatus. The fluid may be seen coming through the upper punctum.
Interpreting Results
- If the patient tastes salty water: the lacrimal drainage system is patent under test conditions i.e. high pressure. Note, this does not exclude “functional” duct obstruction. In other words, the patient may still have obstruction under physiological conditions despite the system being patent under high-pressure testing conditions. If the functional obstruction is suspected (persistent epiphora in the absence of other explanation) further tests are necessary to confirm this - including Jones I and II tests, dacrocystograms, or lacrimal scintigraphy.
- If the patient CANNOT taste salty water: the lacrimal drainage system is blocked. The type of "stop" experienced in inserting the cannula helps to determine the level of blockage:
- Hard stop: the cannula is within the lacrimal sac and touching against the lacrimal bone which suggests a patent canalicular system - the blockage is likely in the nasolacrimal duct.
- Soft stop: the cannula is within the canaliculus and pushing against the spongy outer walls of the lacrimal sac suggesting the blockage is within the canalicular system. If there is regurgitation from the upper punctum it suggests a blockage in the common canaliculus while if there is no regurgitation from the upper punctum it suggests a blockage in the lower canaliculus.
Other Tests of Lacrimal Drainage
- Fluorescein Disappearance Test
- Jones I and II tests
- Dacrocystogram
- Lacrimal Scintigraphy
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