The tear drain consists of 2 small openings (the puncta), one in the upper lid and one in the lower lid, which lead into a pair of small tubes (the upper and lower canaliculus). The small tubes empty into a sac (the lacrimal sac) at the corner of the eye along the nose. The sac leads into a canal (nasolacrimal duct) through bony structures that finally end in the nose (nasal cavity).
With each blink, the eyelids close like a zipper and evenly distribute tears across your eye to keep your eyes moist and healthy. The tears are actively pumped into the sac by the muscles of blinking. Once the tears have been pumped into the sac, they continue down the duct and into your nose.
The system does not have the capacity to drain large amounts of tears. The is why when you cry, your tears build up in your eyes, causing blurry vision and spill down your cheeks. Similarly any stricture or blockage of the drainage system will result in tear build up and tearing.
What other symptoms to look out for?
If the tear drain does not function properly, the tears will back up and spill. The most common symptoms of blocked tear ducts are excessive tearing and mucus discharge. This may lead to blurry vision, recurrent red eyes and chronic infections.
The excessive tearing can additionally produce secondary skin changes on the lower eyelids. Painful swelling in the inner corner of the eyelids may occur. If untreated, complications may include severe infection and scarring of the tear drain.
In some instances, warm compresses and antibiotics may improve symptoms. However, if the duct is blocked, medical treatment is usually not effective in the long run, and surgery is required to restore the drainage.
Dacryocystorhinostomy (DCR) is a surgery performed when there is obstruction of the tear duct (the nasolacrimal duct). DCR surgery bypasses the obstruction by forming a new tear drain between the eye and nose.
The dacryocystorhinostomy (DCR) procedure has a high success rate (more than 90%) for adults who have not had prior nose surgery or disease. The surgery creates a passageway between the tear sac and the nose, bypassing the obstruction. Local or general anaesthesia is used for this procedure. Usually, no skin incision is required and the surgery is performed through the nose. The recovery time is about 2 to 3 days.
A silicone string may be placed temporarily to keep the new tear drain open while healing occurs. The silicone string falls out, or else it is removed, typically 1 to 6 months after placement.
“Vision is the true creative rhythm”
- Robert Delaunay