THE WATERY EYE
Tears are formed by the lacrimal gland, which lies beneath the outer part of the upper lid, and by cells in the conjunctival surface of the eye.
Watering of the eye (epiphora)
This is a very common symptom for which there are a wide variety of causes. In general, the problem results either from an over production of tears or reduced drainage of tears.
Causes of over production of tears
Anything which irritates the eye such as a foreign body or a scratch to the ocular surface will result in epiphora. The watering is a protective mechanism to help clear debris away from the eye.
Watering also occurs in emotive states or as a response to bright lights.
The most common cause of tear production is blepharitis, a condition in which there is an accumulation of debris along the lid margins with resultant inflammation and irritation. This can be treated with regular lid margin cleansing and may require courses of topical or oral antibiotics.
Drainage of tears
Tears are drained from the eye by narrow passages which begin in the inner corner of the eyelids. These canaliculi drain into the lacrimal sac and from here the tears pass down the nasolacrimal duct and into the nose.
Obstruction to tear drainage
Epiphora is a very common problem occurring in up to 45 per cent of infants. There is a membrane at the lower end of the nasolacrimal duct which will open on its own in over 90 per cent of cases by the age of 12 months.
If the symptoms are persisting when the child is one year old, the condition can be cured in 95 per cent of cases by passing a probe along the passageways under a brief general anaesthetic.
Occasionally this should be performed earlier if the child has particularly troublesome symptoms.
Watering may occur at any age and results from a gradual narrowing of the upper end of the nasolacrimal duct, generally from chronic inflammation.
Syringing the tear ducts may give temporary relief but this is mainly used to aid the diagnosis.
The treatment is to make a new passageway for the tears to flow into the nose, bypassing the blocked duct. This is a more major procedure and is generally performed under general anaesthesia.