Watery eyes 22/03/2013

Watery eyes are a relatively common problem, representing one of the symptoms that most often lead patients to consult an ophthalmologist. Watery eyes can cause great discomfort to patients as they have to continuously dry their eyes and may also have blurred vision.

A normal lachrymal system 

A normal lachrymal system begins the inner edge of the eyelid, close to the nose. From here there are two channels, called lachrymal canaliculi, which originate in the upper and lower eyelid and drain into the lachrymal sac, a structure very closely connected to the nasal cavities and paranasal sinuses. The lachrymal sac drains directly into the nose.

Under normal conditions, the volume of tears in the nose is imperceptible as these are reabsorbed, helped by the continual passage of air.

Causes of watery eyes 

There are many causes of watery eyes and the key to successful treatment is therefore based on a thorough initial exploration by a specialised ophthalmologist. One simple way of understanding the condition of watery eyes is to classify it into those cases caused by anomalies in the tear drainage system and those caused by an overproduction of tears.

The lachrymal system can be altered at any stage, from the start of the canaliculi to the nasolachrymal duct. Sometimes the system is permeable to exploration but it does not drain tears properly; this is called functional epiphora as it's the functioning and not the structure of the lachrymal system that's at fault.

Newborn babies can sometimes present a slightly blocked nasolachrymal duct. This is usually due to the immaturity of the system and, in most cases, resolves spontaneously before the child reaches one year of age.

In adults, the most common disorder of the lachrymal system occurs in the nasolachrymal duct. Due to causes that are not known, the duct narrows with age and can even close up completely. This happens most frequently in women over fifty. When the nasolachrymal duct narrows, in addition to watery eyes it may also lead to infection, characterised by pain, reddening and sometimes pus in the area of the lachrymal sac.

When a patient with watery eyes has a normal lachrymal system, we have to look for other causes. In this case it's important to thoroughly explore the surface of the eye as any problem in this zone causes irritation and, as a reflex, an increase in tear production.

Treating blockages of the lachrymal system 

Occlusion of the nasolachrymal duct can only be treated via surgery, called dacryocystorhinostomy (DCR). This operation creates a new channel for the tears, going from the lachrymal sac to the nose and avoiding the blocked nasolachrymal duct. This is outpatient surgery which is carried out under local anaesthesia with sedation in the vast majority of cases.

The least invasive form of DCR is endoscopic, via the nose. This technique achieves very similar results to classic external surgery with the advantage that the operation is shorter, leaves no scars and has a faster recovery.