What happens at a watering eye or lacrimal examination?
When the patient comes to see me with a watering eye, there are several factors that I will assess. First of all, in a lacrimal examination I have to find out:
- how long you have had watering eyes
- whether the watering is affecting one eye or both eyes
- whether the watering is most prevalent in the morning or the afternoon
- whether the watering is most prevalent inside the house or outside the house
I assess these factors as there are many different causes of a watering eye. The history is often the key to telling me where the problem lies.
There is a group of people who have hypersecretion or over-watering where in fact they have dry eyes and their tear producing cells are compensating by trying to produce more tears to wet the eyes. Hence they feel as if their eyes are wet or watering. Often there is a tiny overspill, just a wet sensation.
Assessing the tear film and lid margins in a lacrimal examination
It is essential that I look at the tear film and the lid margins to exclude dry eyes and blepharitis, which is also irritating and causes additional tearing. Once I have eliminated the medical causes of watering eyes, I then start to think a little bit like a plumber. I look to see how much tears there are along the lower lid called the tear meniscus and how efficiently they are getting taken away down the tear tubes.
The eyelid position and its effect on watering eyes
I will put some fluorescein dye in, which will show me the tear meniscus along the lower lid much more clearly when I look at the slit lamp. The dye allows me to measure its height. I then look to see how the little openings at the corners of the lids called the puncta are and whether they are stenosed or wide open. If they are stenosed, I may have to dilate them up or even do a small surgical procedure called One Snip or Two or Three snip.
The tear drainage system and channels
I will then press on the tear sac at the corner of the nose and see whether any of the tears reflux back over the surface of the eye. People who have large sacs and a narrowing of a nasolacrimal duct beyond the sac will often get the tears pooling in the sac because it is so slow for them to drain further out of the sac. Pressure on the sac washes all the pooled tears back over the eye. In “real life” the sac overspills when it is full, so the patients watering may be episodic, only apparent once the sac has filled.
My next step is to gently syringe and probe the tear ducts using a very fine cannula. A cannula is not a sharp needle, but a smooth tipped instrument, which delicately goes down the punctum and canaliculi into the sac. With that, I can detect whether there are any narrowings of the canaliculi or narrowing of the opening into the sac.
I can then irrigate some saline through and see how quickly or slowly it goes down and whether there is any regurgitation of the saline back over the eye because there is either a partial or complete blockage of the tear duct system further along.
Nasal assessment in a lacrimal examination
I will then do a nasal endoscopy. Doing a nasal endoscopy might seem odd to you as I am an eye surgeon, but I have also trained in nasal examination and surgery; however, I trained in tear duct surgery in Boston and then for many years practised endonasal endoscopic DCR in London.
I can assess the opening of the tear duct inside the nose and also exclude other pathologies that could be blocking the tear duct, which has arisen either through nasal problems or from the sinuses. I can look at the quality of the nasal mucosa, the width of the nasal space for surgery, the health of the sinuses and exclude inflammation, tumours, and other swellings.
The mainstay of a lacrimal examination is, therefore:
- The tear film.
- The eyelid margins.
- The eyelid position (because if the eyelid is not in a normal position, the tears will not drain).
- The openings into the tear drainage system.
- The narrow little channels called canaliculi from the surface of the eye at the punctum to the lacrimal sac.
- A nasal examination.
If I need to do any more investigations after the lacrimal examination, these are likely to be x-ray type tests, which are done at the local private hospital and include lacrimal scintigraphy, which is a nuclear medicine test and dacryocystogram. Dacryoscintigraphy is a physiological tear drainage test and gives me an excellent indication as to whether there is a physiological delay because of poor eyelid pumping or an early narrowing of part of the tear duct system.
The dacryocystogram or CT DCG scan can look at the internal lumen of the tear duct drainage system and whether it is narrow or has stones in it and also show me the anatomical structure. All of this will help me work out where the tear obstruction is, which is causing the watering eyes and plan the subsequent surgery, which is most often a dacryocystorhinostomy, more commonly known as DCR.