Tears are produced by the lacrimal glands; each blink lubricates the globe and moves the tears medially towards the nasolacrimal ducts (tear ducts), which drain the tears into the nose. Tearing, also known as epiphora, can be caused by a number of reasons. A patient with tearing needs to have a comprehensive evaluation so the correct cause and treatment plan can be determined. Here are some common reasons for tearing.
• Blepharitis:this is inflammation of the eyelids, and is probably the most common cause of tearing. The oily layer of the tear film is produced by the glands around the eyelid. This layer plays an important role in preventing rapid evaporation of the tears. With inflammation, these oil-producing glands can get clogged. As a result, the tear film will lack this important component and thus evaporate rapidly, leading to dry eye syndrome. The irritated, dry feeling sends signals to the brain to produce more tears, thus the reason for excessive tearing in these patients. The treatment involves treating the underlying blepharitis and use of artificial tears.
• Eyelid malposition: As explained above, the blink dynamic is very important in the proper movement of tears across the eye surface and its drainage into the tear ducts. If the eyelids are malpositioned for whatever reason the patient will have excessive tearing. Previous trauma, tumors, congenital defects, ectropion and entropion are a few causes of eyelid malposition. The patient needs to be evaluated, and reconstructive surgery should be undertaken to correct the underlying cause.
• Nasolacrimal duct obstruction: Also known as the tear duct the nasolacrimal duct is responsible for draining the tears into the nose. This is why a person who is crying will also have a runny nose. If this passage is blocked, the patient will complain of excessive tearing. There are two types of nasolacrimal duct obstruction, congenital and acquired.
• Congenital Nasolacrimal Duct (NLD) Obstruction is a fairly common condition in children whom there is failure of the nasolacrimal duct to open into the nose. If this is the case, tears, mucous, and bacteria cannot be properly cleared from the eye, and as a result the child will have constant tearing. About 80% of congenital NLD obstructions will resolve spontaneously by one year of age. Thus if a child is younger then one, the parents are instructed to massage the nasolacrimal sac (the area near the nose on the lower eyelid) 4 to 5 times a day. If the child has persistent tearing after 12 months of age, a nasolacrimal probing procedure is performed. This procedure is done under general anesthesia. The procedure usually takes just a few minutes, and the infant or child will likely be entirely pain-free afterwards. NLD probing is about 90 to 95% effective and is an extraordinarily safe procedure. For those few infants in which NLD probing fails, a second probing may be attempted or silicone tubes may be placed in the NLD until an open passageway is secured about three to six months after placement .
• Acquired Nasolacrimal Duct Obstruction usually occurs in middle or late adulthood. These patients typically complain of persistent tearing and the tears run out of one eye. This condition is diagnosed by the clinician, who will check with a dye disappearance test or NLD irrigation. If the diagnosis of acquired NLD obstruction is confirmed, the patient may be offered a curative procedure known as dacryocystorhinostomy (DCR).
The DCR Procedure:
Since the nasolacrimal ducts are blocked, the goal of this procedure is to create a new tear drainage path into the nose. There are two ways to perform this procedure. One is the external DCR, which involves making an incision outside the nose. This procedure has a better success rate then the endoscopic DCR, which has no external incisions. Once the new pathway is created, a tiny plastic stent is placed for 3 to 6 months to ensure proper healing of the new drainage system.