The nasolacrimal duct is a duct that connects the lacrimal glands in the eye to the nasal cavity. In this article, we shall briefly review the epidemiology, clinical presentation and the common causes of this condition.
Clinical research has shown that nasolacrimal duct obstruction occurs in 2 to 4 out of 100 newborn babies. However, this number dramatically increases in children who have Down syndrome with statistics suggesting about 22% to 36% developing this condition.
There are a number of different reasons why nasolacrimal duct obstruction occurs. The epidemiological statistics have shown that of all the cases, 35% of them actually due to obstruction, 15% occur due to the improper formation of the opening of the lacrimal duct (punctual agenesis), 10% have some form of abnormal connection i.e. congenital fistula and 5% have defects in the structure of the head and face.
As such, congenital nasolacrimal duct obstruction does not differentiate between race and sex. It is typically seen in newborns.
Congenital nasolacrimal duct obstruction can result in numerous clinical presentations. These conditions bring with them a varying degree of morbidity and mortality.
The first condition that may occur is amniotocoele. Here, there is distension of the tear producing gland i.e. the lacrimal gland. Amniotic fluid enters the lacrimal sac and gets trapped within it. This can result in swelling of the lacrimal sac. Treating this can be done through inserting a small probe through the nasolacrimal duct.
Dacrocystitis is another condition that may develop where there is inflammation and distension of the lacrimal sac. It occurs in the neonatal period which is just after the baby has been born. In these patients as well, probing the lacrimal sac through the nasolacrimal duct is the treatment.
Finally, in newborns who have narrowing of the nasolacrimal duct, accumulation of pus or pus within the lacrimal sac may take place. This can manifest as constant watering of the eye or expulsion of pus from the eye. The treatment usually involves antibiotics, compression and massage of the lacrimal sac. If left untreated, newborns may have matted eyes every morning and excessive tearing of the eyes.
History forms an important part of making a diagnosis. There may be a family history of nasolacrimal duct problems and other abnormalities such as glaucoma. A detailed examination of the eye is useful in determining whether the patient has congenital nasolacrimal duct disease.
A special test known as the dye disappearance test is useful in determining whether there is any obstruction. In addition, tests to ascertain whether the patient has glaucoma need to be conducted.
Nasolacrimal duct obstruction is not very common but does have some recognised causes. The top three causes include –
- genetic causes i.e. having a family history of nasolacrimal duct obstruction
- premature birth
- drug use by the mother during pregnancy
It is commonly accompanied by other eye abnormalities.
9 out of 10 cases resolve within the first year of life. If required, massage therapy over the lacrimal gland may be helpful. In patients in whom this does not work, using a probe can cure up to 95% of cases. Other procedures include the insertion of a tube into the nasolacrimal gland or the insertion of a balloon catheter. Special surgical procedures include a dacrocystorhinostomy – a procedure that helps restore normal tear flow.