Tearing (epiphora) – Nasolacrimal Duct Obstruction
Nasolacrimal duct obstruction (NLDO) is a common cause of epiphora (tearing) in adults. It can also occur from infancy.
What is it?
The nasolacrimal duct is the major tear duct of the whole lacrimal drainage system. It can be obstructed, and usually in its lower third segment. The incidence of NLDO is higher in women, increasing after the age of 40 years old. Up to about 70% of cases of NLDO can develop acute dacryocystitis (inflammation and infection of the tear sac).
What are the causes?
There are 2 main categories of NLDO: that which develops in an adult and that which occurs in a newborn infant (congenital).
NLDO which occurs during adulthood can be either primary-acquired or secondary-acquired NLDO
Primary acquired NLDO is postulated (assumed) to be due to low-grade inflammation causing scarring within the lumen of the nasolacrimal duct, arising from an unknown (idiopathic) cause. Primary-acquired NLDO is the most common form of NLDO in adults. Secondary-acquired NLDO is due to other reasons such as trauma, autoimmune conditions, previous infections, tumours or previous surgery in the nasal cavity near the tear duct.
NLDO which occurs from infancy is what we term as congenital NLDO
The congenital form is due to incomplete development of the nasolacrimal duct in-utero, resulting in incomplete canalisation of the tear duct due to an imperforate valve of Hasner, near the lowest part of the tear duct where it enters the nasal cavity. The baby is born with the problem of tearing. It can be unilateral or bilateral.
What are the symptoms of NLDO?
- Eye discharge
- Pain or swelling between the eyelid and the bridge of the nose
How do we diagnose NLDO?
A dye-disappearance test, followed by a probing and syringing procedure will enable us to diagnose the condition.
Dacryocystorhinostomy (DCR) is the main surgical option for primary-acquired NLDO (commonest type), that essentially aims to create a bone window, which facilitates a communicating route between the tear (lacrimal) sac and nasal cavity, allowing tears to flow straight from the tiny tear ducts (canaliculi) into the nasal cavity, thereby bypassing the obstructed segment of the nasolacrimal duct.