What are the causes of tearing?
Generally speaking, tearing can be due to over-production or under-drainage of tears. Excessive production of tears can result from various conditions that cause eye irritation. A common example is dry eye disease. It may seem strange that dry eye disease can cause tearing. What many fail to realise is that the dryness causes corneal surface erosions and discomfort. When this happens, a reflex is set off that stimulates tear production by the lacrimal gland. This overwhelms the tear drainage system and results in tearing. Under-drainage of tears is usually due to obstruction of the lower portion of the tear drainage (nasolacrimal) duct which drains tears from the tear sac above to the nasal cavity below. This is most commonly due to age-related narrowing of the nasolacrimal duct.
What treatment is available for a blocked tear duct?
The Gold standard treatment for a blocked nasolacrimal duct is either external or endoscopic dacryocystorhinostomy. This involves the creation of a new conduit between the tear sac and the nasal cavity. Part of the surgery requires removal of a small area of bone between the sac and the nasal cavity.
There are pros and cons for each surgical approach and a good discussion with your oculoplastic surgeon will allow you to decide which approach works better for you.