CAUSES OF TEARING

Watery eyes (Excessive tearing) can result from a great number of individual causes or, more frequently, from a combination of problems. For this reason, an individualized approached to the diagnosis and management of tearing is essential for obtaining the desired result.

The causes of watery eyes can be classified into the following categories:

a. Anatomical blockage of the tear duct – based on location:

i. Punctal Stenosis – Lacrimal punctum is the name of the opening of the tear duct on the eyelid margin. The punctum can get blocked any time there is inflammation present on the eyelid margin, as it occurs with dry eyes, allergies, glaucoma medication, ectropion, eyelid laxity, eyelid retraction etc. The rest of the lacrimal duct is usually open, and a simple office procedure called punctoplasty can be performed to open the blocked punctum. However, if the underlying cause of inflammation is not addressed, the rate of recurrence is over 50%.

ii. Canalicular Stenosis – Lacrimal Canaliculus is the name of the small tear duct present inside each eyelid that connects the punctum with the lacrimal sac. Even though there are 2 canaliculi per eye, the disease process that leads to the blockage of the canaliculus tends to affect both the upper and the lower ducts. Most common causes are viral conjunctivitis, allergies, certain cancer medications and many different types of eye drops, especially those used to treat glaucoma (high eye pressure). Treatment of canalicular stenosis can sometimes be very difficult because of the high recurrence rate and needs to be done on an individualized basis, depending on the location and the degree of stenosis. When complete canalicular stenosis is present, a permanent tube called Jones tube is used like a stent to create a direct communication between the inner corner of the eye and the nose.

Congenital Nasolacrimal Duct Obstruction (cNLDO) – Approximately 7% of babies are born with congenital obstruction of the tear drainage system in the nose (the Nasolacrimal duct). This resolves itself in the first year of life in over 90% of cases as the Valve of Hasner begins to spontaneously open. In the 10% of infants where the valve does not open by 1 year of age, a quick procedure can to be done to open it. In rare instances, the bony nasolacrimal duct is partly or completely absent, in which case an endoscopic bypass (Dacryocystorhinostomy) needs to be done around 4 years of age.

Primary Acquired Nasolacrimal duct obstruction (PANDO) – In adults, the most common causes of NLDO are atmospheric pollution, medication, chronic nasal inflammation, allergies, chronic sinusitis and nasal trauma. PANDO leads to tearing and mucus discharge from the eye that can significantly alter one’s quality of life and impair daily activities. The most common complication of PANDO is lacrimal sac infection called Dacryocystitis. This occurs in the majority of patients that have chronic nasolacrimal duct obstruction and can happen at any time. Lacrimal obstruction in adults never resolves itself and a surgical intervention called Dacryocystorhynostomy (DCR) is required. Typically, this procedure is done using an endoscope and has a success rate of over 95%.


i. Facial paralysis – Regardless of whether you recover or not from facial paralysis (Facial Palsy, Bell’s Palsy), the lacrimal pump situated in the inner corner of the eye does not function properly. The tear duct is anatomically open, but the absence of pump function leads to the stagnation of tears in the eye and constant watering. This condition can be dramatically improved by injecting Botox in the eyelid (if aberrant regeneration is present) or by correcting the paralytic ectropion (whenever the case).

ii. Eyelid laxity – The lacrimal pump depends on the proper horizontal tightness of the eyelids. Any disease or condition that makes the eyelids become loose can impair the functioning of the lacrimal pump and result in tearing. Floppy Eyelid Syndrome (FES) is a condition that results in extreme eyelid laxity and is seen in the majority of patients suffering from Obstructive Sleep Apnea (OSA). The use of the CPAP machine in these patients can slow down or even halt the progression of eyelid laxity.

iii. Ectropion (eyelid turned out) – An eyelid turned outwards can lead to chronic tearing by 3 mechanisms. First, the eye becomes exposed to the air which makes it drier and irritated. Consequently, the lacrimal gland produces an excessive amount of tears. Second, the lacrimal punctum does not come any longer in contact with the tear lake when the eyelid turns out. And, third, the lacrimal pump does not function in the presence of a loose eyelid turned outwards. All 3 mechanisms need to be addressed in order to obtain an adequate improvement in tearing. Sometimes, a 4th mechanism is associated: punctal stenosis from the chronic inflammation of the eyelid exposed to the air. This is usually resolved at the same setting.

iv. Eyelid retraction – When the eyelid is pulled downwards from various pathologies it does not protect the eyeball and does not function as a good windshield wiper, resulting in a dry and irritated eye. This results in a reflex overproduction of tears by the lacrimal gland. Frequently, the lacrimal pump is also impaired due to the associated eyelid laxity, further exacerbating the tearing. Proper correction of any eyelid malposition (adequate eyelid position) is mandatory to improve tearing in theses cases.


a. After facial paralysis – Aberrant regeneration of the facial nerve after VII nerve palsy (Bell’s palsy) can lead to a branch of the trigeminal nerve (the 5th cranial nerve involved in chewing) being mis-wired to innervate the lacrimal gland. Consequently, the eye starts to water spontaneously during eating. This condition cannot be prevented but can be successfully treated with Botox injections into the lacrimal gland.

b. Trichiasis (misdirected lashes) – Any eyelash rubbing on the eyeball leads to the reflex over-production of tears. This condition can be treated by permanently removing the offending lashes in the office with a special radiofrequency device.

c. Entropion (Eyelid turned in) – When the entire eyelid is turning in, a condition known as entropion, the eyelashes and the lid margin can rub severely against the eyeball resulting in irritation and sometimes a corneal ulcer. The lacrimal gland immediately starts producing tears in an effort to relieve the irritation. Untreated, entropion can result in corneal scarring and permanent vision loss.

d. Dry eyes – A great number of conditions can result in dry eye syndrome or simply dry eyes. Systemic diseases such as Sjögren’s, Reumatoid arthritis, Lupus and Graves disease are among the most common. Dry eyes is also an occupational disease encountered in over 60% of the population today. The combination of computers, smart-phones and air conditioning can all impair the ocular surface for which reason the dry eye syndrome is now seen in many young people, including children. Dry eyes is a frequent cause of reflex tearing (secondary to eye irritation) in which case it is often mis-diagnosed and treated as conjunctivitis. Dry eyes can also result from anatomical problems related to the eyelids’ role as windshield wipers. Eyelid malpositions (abnormal eyelid position) usually need to be corrected, otherwise the use of artificial tear drops and ointments has only a minimal benefit. The most common eyelid problems leading to dry eyes and consecutive tearing are:

i. Ectropion (eyelid turned out) – when the lower eyelid turns outward, it doesn’t protect the eyeball any more and it doesn’t function as a windshield wiper to lubricate the eye. Consequently, the eye surface gets dry and irritated which triggers an overproduction of tears from the lacrimal gland. This results in watery eyes, worse when reading, watching TV or working on the computer. Patients are frequently misdiagnosed as having a conjunctivitis and are given antibiotic-steroid drops that do more harm than good. The only therapeutic option for ectropion is surgical repair which corrects the dry eye syndrome and reactivates the lacrimal pump.

ii. Eyelid laxity – When the eyelids become loose from different pathologies, they don’t protect and lubricate the eyes as they should, and the eyes become dry. Through a trigeminal reflex, the lacrimal gland is stimulated to produce an excess of tears and the eyes become watery. However, the eyes feel more dry than wet and the episodes of tearing are usually preceded by dry eye symptoms such as: irritation, burning, itching and blurry vision.

iii. Eyelid retraction – When the upper and/or lower eyelid is retracted and not protecting the eyeball, dry eyes and irritation occur, which triggers the production of tears by a reflex mechanism. Unfortunately, these tears are not of good quality because they are produced by the lacrimal gland and are too watery. This is the reason why, when one cries because of feeling sad, the eyes become red and irritated. Using artificial tears that are lubricating can temporarily relieve the symptoms and paradoxically block the tearing. However, permanent correction of the eyelid retraction is usually necessary.

e. Allergies – There are two mechanism by which allergies lead to watery eyes. The itching and irritation produced by the release of inflammatory molecules onto the ocular surface leads to reflex tearing. In addition, the inflammation throughout the lacrimal drainage system can frequently lead to anatomical blockage (obstruction) of the tear duct. This can happen anywhere from the punctum to the nasolacrimal duct and can be permanent. Sometimes, rapid and effective intervention can decrease the inflammation and allow the tear duct to reopen. The treatment is usually with allergy eye drops but surgical intervention is sometimes necessary.