Lacrimal syringing is a simple procedure done to evaluate the patency of the lacrimal system. It is done in the outpatient clinic, and the patient does not feel any significant discomfort. It is not a surgical procedure but a simple OPD procedure.
The lacrimal system consists of two parts: one is the lacrimal gland that secretes the tear fluid on the eye's front surface. The lacrimal gland is situated in the upper eyelid corner toward the ear. The second is the drainage mechanism. As shown in the diagram, the drainage mechanism consists of puncti ( singular - puncta), canaliculi, the lacrimal sac, and the nasolacrimal duct. These are also known as tear ducts.
The tear duct drains the tear fluid from the lacrimal sac into the nose. It is the most common site of a lacrimal drainage system block.
In the diagram above, you will notice a lacrimal sac and a nasolacrimal duct. The tear fluid collects in the sac and then flows down into the nose through the nasolacrimal duct. The tear fluid accumulates in the lacrimal sac whenever the nasolacrimal duct is blocked. The liquid in the lacrimal sac tends to get infected.
The Roplas test is when your doctor presses the lacrimal sac, and this infected fluid flows in the reverse direction and flows out through the puncti onto the eye's surface. A Roplas positive would mean that the nasolacrimal duct is blocked, and a Roplas negative would mean that the nasolacrimal duct is patent or not blocked.
The lacrimal syringing test is done to test the patency of the lacrimal drainage system. When patients complain of continuous watering, it could mean that they have a blocked drainage system. This test will help us identify a block and further help us localise the block.
Sometimes syringing is also done as a presurgery test, usually before cataract surgery. Your doctor wants to rule out any focus of infection in and around the eye. If the lacrimal drainage system is blocked, one cannot undergo cataract surgery until we treat that blocked duct.
We start by preparing a 2ml syringe with distilled water or sterile saline. We attach a 27g cannula to this syringe. We then numb the eye with eye drops. The lower lid is everted with a finger to make the lower puntum visible. Once visible, we insert the 27g cannula in the puntum, and we then turn the cannula to enter the canaliculus.
We then inject water and wait for the response. If the nasolacrimal duct is patent or not blocked, the patient will get water in the nose or throat. Patients are instructed that they will get some water with a salty taste in their throat, and they must swallow the water. On the other hand, if there is a nasolacrimal duct obstruction, then the fluid will come back out onto the eye's surface. This fluid comes back out from the upper punctum.
Sometimes the puncti are very narrow, and the cannula cannot enter the canaliculus. So even though the lacrimal apparatus may be open, one will never know till your doctor cannot do the syringing test. In these situations, we use a punctum dilator that widens the punctum's opening. We then try and insert the cannula through this wider punctum.
We use topical anaesthesia or eye drops. These are numbing eye drops, and their effect lasts for a few minutes. As mentioned earlier, this is a minor and painless procedure.
Sometimes children are born with blocked nasolacrimal duct in one or both eyes. Usually, they get better on their own with a massage over the lacrimal sac. These children may need a procedure called probing and may even require surgery later when they are older.
If the lacrimal ducts are blocked, then one may need corrective surgery. Different surgeries can be suggested depending on which part of the lacrimal passage is blocked. Most commonly, there is a nasolacrimal duct obstruction. The procedure for this is DCR which involves creating a new opening between the lacrimal sac and the nose. DCR is a very effective procedure for nasolacrimal duct obstructions.