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.

Epiphora is the term commonly used to describe a watery eye. More specifically, lacrimation describes persistent welling of tears in the eye and epiphora is when these spill over. It is caused by:

• Overproduction of tears
• Inadequate/blocked drainage

Patients tend to experience this as a nuisance more than anything else. However, both lacrimation and epiphora can be associated with interference in vision ("It's like looking through pool water all the time.") 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.

Aetiology¹

Overproduction of tears:

• Lid or lash malposition, e.g. trichiasis or entropion.
• Lid margin disease, e.g. blepharitis.
• Tear film deficiency (inappropriate reflex reaction).
• Corneal foreign body.
• Conjunctivitis.
• Corneal disease.
• Inflammatory disease, e.g. uveitis, scleritis.
• It may occasionally be a presentation in congenital glaucoma.

• Punctal malposition (lid laxity, e.g. ectropion).
• Stenosis or obstruction at any point along the nasolacrimal duct, e.g. congenital nasolacrimal duct obstruction - the most common cause of epiphora in childhood, lacrimal sac mass or mucocele, dacryocystitis.
• Lacrimal pump failure, e.g. facial palsy.
• Nasal obstruction, e.g. mass, inflammation or scarring.
• Previous surgery or trauma.

Presentation²

Epiphora is simply a watering eye. There may be additional symptoms or signs depending on the underlying aetiology - follow links above. There are a few pointers that can help guide your 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, e.g. 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).

Investigation²

In the eye clinic, steps are taken to identify which of the two groups of conditions the epiphora falls in, then refining the diagnosis through clinical examination ± investigation. Assessments include:

• Fluorescein disappearance test: a tiny drop of fluorescein 2% is instilled at the start of history. After about 5 minutes, a judgement is made about tear film height and dilution of the fluorescein. If the tear film is high and the fluorescein diluted, there is overproduction. If it remains undiluted, there is impaired drainage.
• 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.
• Dacryocystogram (DCG): radioactive isotope is injected into the nasolacrimal duct and its passage is recorded with a series of sequential pictures. This is a useful investigation both to assess whether there is patency or not and the level of any obstruction - a good predictor of surgical outcome.³
• Sinonasal disease or tumours warrant CT scan ± nasoendoscopy occasionally.

Management²

This depends on the underlying cause - see links above. If the symptoms are severe or you are unable to discern the underlying cause, non-urgent referral is appropriate.

• 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 (e.g. balloon catheter insertion) should be used if the condition recurs after treatment.⁴
• Dacryocystorhinostomy (DCR) is the procedure that creates an anastomosis between the lacrimal sac and the nose. The procedure may be external (open) or endoscopic, the former still being considered the gold standard. Although there are more associated complications (rare in themselves), the success rate is 90-95% compared with 80% success with endoscopic surgery and 70-80% success with endoscopic laser procedures.
• There is a variant - conjunctivodacryocystorhinostomy (CDCR), which is used for canalicular obstructions. The technique has been improved by the use of modern materials such as polyurethane to replace the standard Lester Jones drainage tube usually inserted during the procedure.⁵
• Other options tried include the use of balloon catheters, stents and silicone tubes (although one meta-analysis found that endoscopic surgery was as successful without subsequent placement of silicone tubes as with them).⁶

Document references

1. Beigi B; Epiphora, 2011
2. Camara JG et al; Obstruction Nasolacrimal Duct, Medscape, Jan 2010
3. Choi JC, Jin HR, Moon YE, et al; The surgical outcome of endoscopic dacryocystorhinostomy according to the obstruction levels of lacrimal drainage system. Clin Exp Otorhinolaryngol. 2009 Sep;2(3):141-4. Epub 2009 Sep 23. [abstract]
4. Cha DS, Lee H, Park MS, et al; Clinical outcomes of initial and repeated nasolacrimal duct office-based probing Korean J Ophthalmol. 2010 Oct;24(5):261-6. Epub 2010 Oct 5. [abstract]
5. Chaloupka K, Motwani M, Seifalian AM; Development of a new lacrimal drainage conduit using POSS nanocomposite. Biotechnol Appl Biochem. 2011 Sep-Oct;58(5):363-70. doi: 10.1002/bab.53. [abstract]
6. Gu Z, Cao Z; Silicone intubation and endoscopic dacryocystorhinostomy: a meta-analysis. J Otolaryngol Head Neck Surg. 2010 Dec;39(6):710-3. [abstract]