What is Nasolacrimal Duct Obstruction?
Nasolacrimal duct obstruction (NLDO), also known as dacryostenosis, is a common issue affecting the tear duct system. It is reported that 6% to 20% of newborns show some symptoms of this condition. Usually, NLDO appears in the first weeks or months after birth when normal tear production starts. It shows up as too much tearing and eye discharge.
Redness of the skin around the eyes and both upper and lower eyelids can occur due to irritation from constant tear flow and discharge caused by poor drainage. As such, the condition might look like a long-lasting unilateral, meaning one-sided, conjunctivitis (pink eye). Fortunately, most cases clear up on their own or with little intervention within the baby’s first year. However, unresolved issues should be referred to a pediatric eye doctor, who may need to probe the tear duct or even consider surgery.
For children under six months, doctors usually take a more cautious approach to treatment. Techniques like massaging the tearduct area, eye drops, and topical antibiotics are the first choice. Surgery is only considered for those still experiencing symptoms after their first birthday.
What Causes Nasolacrimal Duct Obstruction?
The tear drainage system starts forming during the fifth week of pregnancy. This structure, known as the nasolacrimal groove or naso-optic fissure, forms between the forehead and upper jaw processes. During this time, a cord of basic tissue separates from the surface and enters this groove. This tissue eventually creates a tunnel and forms the tear sac and nasolacrimal duct, which are parts of the tear drainage system. This tunneling process usually starts by the 8th week of pregnancy and is finished by the time the baby is born.
Tears are produced by the main and extra tear glands. They drain towards the middle of the eye into small openings, known as puncta, then flow through small tubes called the canaliculi to the tear sac, and then through the nasolacrimal duct into the nose.
The most common cause of a blocked tear duct at birth, or congenital nasolacrimal duct obstruction (NLDO), is when this tunneling process isn’t completed, which takes place at the duct’s farther end resulting in an unopened membrane at the Hasner’s valve, a part of the tear drainage system at the nose’s lower end. This incomplete process means the duct doesn’t open up as it should, resulting in a blocked tear duct.
Risk Factors and Frequency for Nasolacrimal Duct Obstruction
Congenital nasolacrimal duct obstruction is a condition that affects about 6% to 20% of infants. However, many children naturally get better as they grow – about 70% are symptom-free by three months old, and over 90% have recovered by their first birthday. There are still some cases where symptoms persist beyond the child’s first year of life. For these cases, medical treatment might be needed to clear the blocked tear duct.
- About 20% of healthy infants show signs of this condition in their first year.
- By six months, 90% of affected babies get better on their own.
- If symptoms are still present in babies aged 6 to 10 months, about two-thirds will improve within the next six months.
- When the condition continues beyond 12 months, a medical procedure may be needed to clear the blockage.
- In some severe cases, where the condition doesn’t improve with two or more treatment attempts, 35% have a blocked tear duct, 15% are born without a tear duct opening, 10% have abnormal connections between the tear duct and other tissues, and 5% have birth defects that affect the head and face.
The condition affects boys and girls equally, and there doesn’t seem to be any differences among different races. However, babies born with certain genetic conditions, such as Trisomy 21, EEC syndrome, branchiooculofacial syndrome, CHARGE syndrome, and Goldenhar syndrome, have a higher risk of having congenital nasolacrimal duct obstruction.
also develop in the presence of nasolacrimal duct obstruction or canaliculitis
Signs and Symptoms of Nasolacrimal Duct Obstruction
Babies with a congenital condition called nasolacrimal duct obstruction (NLDO) exhibit persistent or occasional tearing up and remnants on their eyelashes. It’s common for these babies to have a larger tear meniscus, the curved edge formed by tear fluid. A physical examination may also show that pressing on the tear sac causes tears or a mucus-like fluid to ooze back onto the eye. Unlike what you might expect, signs of this condition don’t usually include redness in the conjunctiva, the inside of the eyelids and the white part of the eye. However, the constant tearing and frequent eye rubbing due to irritation could result in a mild redness of the lower and upper eyelid.
Obstruction of the nasolacrimal duct, when present, may lead to several complications as the immobile fluid in the tear system encourages bacterial growth. Ideally, tears drain out of this duct helping flush away normal bacteria in the process. However, under certain conditions like wind and cold weather that cause increased tear production, this partial drainage might be insufficient leading to an overflow of tears. In case of NLDO, the accumulated tear fluid in the lacrimal sac forms a conducive environment for bacterial growth.
A small percentage of infants with NLDO may present with acute dacryocystitis, a severe infection, within their first few weeks of life. Symptoms include swelling, redness, and enlargement of the tear sac beneath the medial canthal tendon (corner of the eye nearest to the nose). Some infants may also show signs of a systemic infection such as irritability and fever. Although quite rare, severe cases of this type can lead to further complications like preseptal or orbital cellulitis (infection of the eyelid or the tissues surrounding the eye), sepsis, or meningitis. If such severe symptoms are observed, immediate administration of antibiotics is required. However, the best treatment is often surgery.
Testing for Nasolacrimal Duct Obstruction
Diagnosis of a medical condition is usually based on the patient’s symptoms and a physical check-up. However, if symptoms come and go and there are no clear signs of tear problems or “gunk” buildup when the doctor checks, a special test can be used to confirm the diagnosis. This test is called the dye disappearance test.
In this test, the doctor uses a drop of a special salt solution which is colored with a dye called fluorescein. This drop is placed in the lower corner of the patient’s eyes. Any extra tears are gently wiped away from the eyelids. After waiting for 5 minutes, the doctor checks the eyes again. If the colored solution has completely drained into the nose within that time, it suggests that the patient’s tear drainage system is working well and not blocked. This result can help the doctor confirm their diagnosis.
Treatment Options for Nasolacrimal Duct Obstruction
The standard way to treat a simple case of a blocked tear duct (nasolacrimal duct obstruction or NLDO) usually involves massaging the area around the eye two or three times a day, cleaning the eyelids with warm water, and using eye drops that are antibiotics to manage any kind of infection. This approach tends to clear up the problem in between 76% to 89% of cases. If there’s an excess of thick, yellowish mucus coming out of the eye, eye drop antibiotics are typically used to help control it. If the skin on the eyelids becomes too soft and starts to break down, a gentle eye cream can be used.
If a baby’s blocked tear duct doesn’t resolve by the time they’re between six to ten months old, a specialist doctor who treats eye problems in children (pediatric ophthalmologist) may use a tiny piece of medical equipment called a ‘probe’ to clear the blockage in the tear duct. This can be done in their office or in an operation room (for cases with nasal cysts or infections) depending on the child’s age. During this procedure, the probe is gently passed through the tear duct until it reaches the blockade and it is then pushed further to clear the blockage into the nose. To ensure the tear duct is now clear, a colored saline solution is often flushed through the tear duct system.
When a child has an eye infection or skin infection (cellulitis) at the same time as a blocked tear duct, they will first be given antibiotics throughout their entire body, after which the probing will be done. The benefits of early probing in the doctor’s office include not having to put your child under general anesthesia, quick relief of symptoms, fewer doctor’s visits and antibiotic prescriptions, and a less expensive procedure.
What else can Nasolacrimal Duct Obstruction be?
There are many possible conditions that could be causing eye issues in a baby, which could include:
- Conjunctivitis (pink eye)
- Corneal abrasion (a scratch on the eye)
- Uveitis (inflammation inside the eye)
- Hemangiomas (a benign tumor of blood vessels)
- Dermoids (a type of cyst)
- Nasal gliomas (a rare soft tissue tumor)
- Infantile glaucoma (a serious eye condition).
The absence of additional signs and symptoms helps to distinguish a blocked tear duct, known as Congenital Nasolacrimal Duct Obstruction (NLDO), from these other causes of excessive tearing.
Most infants with a blocked tear duct can successfully be diagnosed and managed by their primary physician. However, if the doctor is unsure about the diagnosis, especially if they suspect glaucoma or if there are signs or symptoms of two conditions known as dacryocystitis or dacryocystocele, a specialist called an ophthalmologist might be needed.
