Epiphora

The tear film is a complex and important entity that provides corneal lubrication, nourishment and immunological protection among other functions. The air/tear interface is also the most important site of light ray refraction.

Tears drain into the upper and lower puncta medially, into their respective canaliculi and then into the common canaliculus. From there, they enter the lacrimal sac (adjacent to the bridge of the nose) and then down into the nasolacrimal duct, to exit just beneath the inferior turbinate.

What is epiphora?

Epiphora is defined as excessive watering of the eye. The process of tearing includes several steps such as formation in the lacrimal gland, spreading through eye blinking, vaporisation from the ocular surface, and draining through the nasolacrimal duct. Abnormalities in any of these steps can cause epiphora.¹

Lacrimal outflow can be compromised by anatomical obstructions or stenoses (non-functional epiphora) or by defective lacrimal 'pump' function (functional epiphora).²

Patients tend to experience this as a nuisance more than anything else. However, both lacrimation and epiphora can be associated with interference in vision and the surrounding skin can get very sore and excoriated from the constant wiping of tears associated with epiphora. There may also be underlying conditions that need to be addressed.

Epiphora can cause visual disturbance and affect a broad array of daily activities. Corrective measures for epiphora can improve vision-related quality of life.³

What causes epiphora? (Aetiology)¹

There are many causes of an imbalance between tear formation and tear loss, leading to epiphora. Excess tear production directly leads to tearing, whereas tear loss stimulates reflective and spontaneous tear production, which may also result in epiphora.

Most imbalances in tear quantity are caused due to nasolacrimal duct stenosis, and obstruction at a different level of lacrimal outflow system, eyelid malposition, lacrimal pump failure, and dry eye with reflex tearing. However, a combination of these causes may occur.

The possible causes of epiphora therefore include:

Overproduction of tears (functional epiphora):

See also the article on Conditions Affecting the External Eye.

• Lid or lash malposition - eg, trichiasis or entropion.

• Lid laxity, eg, ectropion.

• Lid margin disease - eg, blepharitis.

• Tear film deficiency (inappropriate reflex reaction).

• Corneal foreign body.

• Conjunctivitis.

• Corneal disease.

• Inflammatory disease - eg, uveitis, scleritis.

• It may occasionally be a presentation in congenital glaucoma.

Stenosis or obstruction at any point along the nasolacrimal duct:

• Congenital nasolacrimal duct obstruction - the most common cause of epiphora in childhood.

• Lacrimal sac mass or mucocele.

• Dacryocystitis.

• Lacrimal pump failure - eg, facial palsy.

• Nasal obstruction - eg, mass, inflammation or scarring.

• Previous surgery or trauma.

Epiphora symptoms (presentation)

There may be additional symptoms or signs depending on the underlying aetiology. There are a few pointers that can help guide diagnosis:

• Medial spillage suggests impaired drainage.

• Lateral spillage is more common with lower lid laxity.

• Reflex watering from a tear film deficiency is more likely to occur in dry, warm conditions or where blink rate is reduced - eg, computer work.

• A simultaneous runny nose suggests overproduction.

• 'Crocodile tears' are associated with facial palsy and arise as a result of neurogenic reflex watering (thought of food, eating or chewing).

Investigations

Investigations will depend on the clinical situation and the cause may be evident from clinical assessment. However, investigations may include:⁴

• Schirmer Test:

  • The patient sits upright. A Whatman filter paper is folded at an angle of 90 degrees. The strip is 35 mm by 5 mm. The end is bent at about 5 mm, and this short tail is placed in the inferior fornix between the medial two-thirds and lateral one-third of the lower eyelid.

  • The patient is asked to blink normally in a semi-dark room for five minutes. The distance to which tears have travelled is read from the filter paper.

  • In patients under the age of 40 years, the wetting is more than 15 mm. In patients over the age of 40 years, 10 mm is considered normal. Anything less than 5 mm indicates abnormally low aqueous tear production.

• Examination of the tear film and cornea:

  • A drop of 2% fluorescein is placed at the lateral canthus, and the patient is asked to blink.

  • With the lids open, there should be a 1-mm tear film along the upper and the lower eyelid margin.

  • A poor tear film may indicate dry eye syndrome (keratitis sicca).

  • The cornea may also be examined.

• Tear break-up time:

  • The patient is asked to blink after the placement of the fluorescein in the eye.

  • Normally, the tear film breaks up after 15 seconds. Anything shorter may indicate a deficiency in the mucus component of the tear film or an excessive aqueous component.

• 
  Fluorescein disappearance test:
  

• • After a drop of 2% fluorescein has been placed in the fornix, the fluorescein remaining in the conjunctival cul-de-sac is examined with the cobalt blue light after five minutes.

  • The amount of remaining fluorescein can be graded using a scale from 0 to 4, where 0 indicates no remaining dye, and 4 indicates all the dye remains. This is also compared to the opposite eye.

  • Retention of the fluorescein indicates a delay in tear flow. If the result is normal, lacrimal drainage dysfunction is unlikely.

• Syringing:

• • Saline is irrigated through the canaliculi via the puncti after instilling a drop of local anaesthetic.

  • Reflux through the upper canaliculus suggests obstruction at the common canaliculus.

  • If the patient feels it trickling at the back of the throat, there is some degree of patency at least.

• Nasal endoscopy.

• Dacryocystogram (DCG):

• • Radioactive isotope is injected into the nasolacrimal duct and its passage is recorded with a series of sequential pictures.

  • This can be a useful investigation both to assess whether there is patency or not and the level of any obstruction.

• CT, MRI scans and nasoendoscopy may be undertaken - eg, for sinonasal disease or tumours.

Epiphora treatment and management

This depends on the underlying cause.

Impaired drainage due to lid malposition or stenosis at various points along the nasolacrimal duct usually involves surgery.

• Simple probing may suffice and is particularly successful in non-resolving congenital nasolacrimal duct obstruction. One study suggested that the success rate falls with repeated probing and that other techniques (eg, balloon catheter insertion) should be used if the condition recurs after treatment.⁵

• Dacryocystorhinostomy (DCR) is among the common oculoplastics surgeries performed for managing epiphora due to nasolacrimal duct obstruction. It is a bypass procedure that creates an anastomosis between the lacrimal sac and the nasal mucosa via a bony ostium.⁶ It may be performed through an external skin incision or intranasally with or without endoscopic visualisation.⁷

• Powered endoscopic DCR is a safe procedure and offers excellent long-term results both in primary and revision DCRs.⁸ One study has demonstrated final anatomical success of 97.7% and functional success in 95.5% of the cases with this technique.⁹

• Functional epiphora after DCR occurs in 5-10% of cases.¹⁰ This is often managed with intubation (transient or permanent) or eyelid tightening.

• No benefit has been shown for silicone tube intubation in primary DCR.¹¹