What is Nasolacrimal Duct Obstruction?
Nasolacrimal duct obstruction (NLDO) is a condition of a blocked tear duct, in which your tears can’t drain normally, leaving you with a watery eye. It can be a partial or complete obstruction.
What are the symptoms of NLDO?
In patients with NLDO, tears don’t drain properly, resulting in a watery eye and an increased risk for eye infections and inflammation. Patients usually present with excessive tearing, mucus discharge, eye irritation, gummy eyelid or blurring of vision, sometimes even with painful swelling at the inner corner of the eye. Some have a history of pressure on the lacrimal sac which causes mucus reflux from the punctum.
What are the causes of NLDO?
Blocked tear ducts can happen at any age. They may be congenital (present at birth) or acquired. Causes for NLDO include:
- Congenital blockage – Many infants are born with a blocked tear duct. The tear drainage system may not be fully developed or there may be a duct abnormality. Often a thin tissue membrane remains (and obstructs) the opening that empties the tears into the nose (nasolacrimal duct).
- Age-related changes – As you age, the tiny openings that drain tears may get narrower, causing a blockage.
- Infection or inflammation – Any chronic infection or inflammation of your eyes, tear drainage system or nose can cause your tear ducts to become blocked.
- Injury or trauma – An injury to your face can cause bone damage or scarring near the drainage system, disrupting the normal flow of tears through the ducts.
- Tumour – A tumour in the nose or anywhere along the tear drainage system can cause blockage.
- Inflammatory conditions – Disorders that cause swelling, such as sarcoidosis or granulomatosis with polyangiitis, can increase the risk of developing a blocked tear duct.
- Eyedrops – Rarely, long-term use of certain medications, such as eyedrops used to treat glaucoma, can cause a blocked tear duct.
- Cancer treatments – A blocked tear duct is a possible side effect of chemotherapy and radiation treatment for cancer.
- Sinusitis – A chronically inflamed nasal mucosa can increase the risk of developing a blocked tear duct.
How to diagnose NLDO?
To diagnose this condition, your doctor talks with you about your symptoms, examines your eyes and does a few tests. He or she will also examine the inside of your nose to determine if any structural disorders of your nasal passages are causing an obstruction. If your doctor suspects a blocked tear duct, you may have to undergo other tests to identify the location of the block.
Tests used to diagnose a blocked tear duct include:
- Dye disappearance test or tear drainage test – This test measures how quickly your tears are draining. One drop of a dye called flourescein is placed on the surface of each eye. If most of the dye still remains on the surface of the eye after 5 minutes, it is very likely that the cause is a blocked tear duct.
- Lacrimal syringing – Your doctor may need to assess how well your tear drainage system is functioning. To do this, normal saline willed be flushed through the drainage system (after instilling some topical anaesthetic). This is done using a slender instrument called a lacrimal cannula, which injects the saline through the tiny drainage holes at the corner of your lid (puncta). The outcome of this procedure will indicate any one of the following:
- if saline passes into the nose or throat (patient swallows and tastes salt) – the nasolacrimal system is patent
- if there is resistance to the passage of the cannula and there is backflow of saline from the opposite canaliculus – the common canaliculus is narrowed
- if no saline passes into nose – complete lacrimal duct obstruction
- Eye imaging tests such as dacryocystogram – Dacryocystogram is a special x-ray procedure that is done to visualize the lacrimal duct of the eye following the injection of contrast (x-ray dye) into the duct. For these procedures, the dye is used to obtain images to help identify the location and cause of blockage.
What are the treatment options for NLDO?
The treatment of NLDO depends on the specific cause. You may need more than one approach to correct the problem. There are non-surgical and surgical treatment options for NLDO.
Non-surgical options includes:
- Antibiotics – If an infection is present, your doctor may prescribe antibiotic eyedrops or tablets to treat the infection first.
- Watch-and-wait or digital massage – Babies born with a blocked tear duct often get better without any treatment. This can happen as the drainage system matures during the first couple months of life. Often, a thin tissue membrane remains over the opening that empties into the nose (nasolacrimal duct). Your doctor may teach the parent a special massage technique to help open the membrane. This can be achieved with gentle pressure using a finger over the common canaliculus, firmly stroking downwards (approximately 10 times) to raise the pressure within the lacrimal sac, thereby encouraging the opening of the valve. This should ideally be performed twice daily with regular cleansing of discharge from the lids.
- Dilation, syringing and probing – For infants, this technique is done under general anaesthesia. The doctor enlarges the punctal openings with a thin probe through the puncta and into the tear drainage system. For adults with partially narrowed puncta, your doctor may dilate the puncta with a small probe and then flush (irrigate) the tear duct. This is a simple outpatient procedure that often provides at least temporary relief.
- Balloon catheter dilation or dacryocystoplasty – If other treatments haven’t worked or the blockage returns, this procedure may be used. It’s usually effective for infants and toddlers, and may also be used in adults with partial blockage. Under a general anesthetic, the doctor threads a tube with a deflated balloon at the tip through the tear duct blockage. The balloon is repeatedly is inflated and deflated to open up the blockage.
- Stenting or intubation – This procedure is usually done under general anesthesia. A thin tube, made of silicone or polyurethane, is threaded through one or both puncta in the corner of your eyelid. These tubes then pass through the tear drainage system into your nose. A small loop of tubing will stay visible in the corner of your eye and is generally left in for about three months before being removed. Possible complications of stenting include inflammation from the presence of the tube.
Surgical options include:
- Dacryocystorhinostomy (DCR) – A DCR essentially creates a bypass under the skin of the inner corner of the eye to allow the tears to drain more directly into the nose. A DCR results in a short-cut between the lacrimal sac (which lies under the skin in the very corner of the eyelids) and the nose, with a channel connecting the two structures created in the bone. Any blockage or narrowing of the nasolacrimal duct is completely bypassed with this surgery.
A DCR is usually done under general anaesthesia or intravenous sedation. A DCR can be done externally or endoscopically. In an external dacryocystorhinostomy, the surgeon makes an incision on the side of the nose, near the lacrimal sac. After connecting the lacrimal sac to your nasal cavity and placing a silicone stent in the new passageway, the surgeon closes up the skin incision with a few stitches. With endoscopic or endonasal DCR, the procedure is done through the nasal end of the tear duct, thereby requiring no incision – and no residual scar. However, the success rates aren’t as high with the endonasal approach as with the external procedure.
What is the post-op care for DCR?
Following surgery, nasal decongestant sprays and eyedrops are used to prevent infection and reduce inflammation. The first review occurs 1-2 weeks after surgery, when the skin stitches (external DCR) are removed. At the second clinic visit two or three month later, the silicone stent is removed, and no further review is necessary. However, future appointments can easily be arranged if any further ocular or lacrimal symptoms occur.