Marie first mentioned Archie’s eye problem when she brought him in for his annual health check in September. At that stage, she told me that both his eyes seemed red, and they looked as if there was some sort of film over the surface. When I looked at him, I agreed that Archie’s eyes seemed to have a duller surface than normal.
The most common cause of this problem is “Dry Eye”. The tear glands in one or both eyes stop producing as many tears as normal, so the eye literally dries out. This dryness causes increased friction between the inside of the eyelids and the surface of the eye, resulting in a painful, uncomfortable eye. Some breeds, including Cavalier King Charles Spaniels, are prone to Dry Eye, especially in middle age. I did a simple test on Archie to confirm the diagnosis.
The test is called the “Schirmer Tear Test”: a short strip of filter paper is placed into the eye, and the amount of tears produced is measured in millimetres over one minute. A normal dog produces more than 15mm of tears; a dog with advanced Dry Eye may produce no tears at all. Archie’s test result was normal in his left eye, but the tear production in his right eye was reduced, at only 9mm. Archie was in the early stages of developing Dry Eye. I gave him a course of eye drops to treat any underlying infection which could be temporarily decreasing his tear flow, and I arranged to see him a month later.
When he came back in October, the tear flow in his right eye had increased to 14mm: this was very nearly normal. His eye was comfortable again, and the redness had gone away. I still suspected that he was on the verge of developing a longer term problem, but for the time being, no more treatment was needed.
The problem returned last week: Marie noticed that Archie’s eye was half closed, first thing one morning. She brought him back and I measured his tear flow again. This time the tear flow in his right eye was down to 12mm: significantly less than normal. I discussed the treatment options for Dry Eye with Marie.
The ideal answer is a special anti-inflammatory ointment. Dry eye is caused by inflammation of the tear glands, and regular application of the special ointment is sometimes enough to restart the tear flow. However it’s a pricey ointment, and not every case is severe enough to require it.
A simpler treatment is regular application of artificial tears. These are less expensive, and they work by simply replacing the tears that the dog ought to be producing naturally. Archie only has a mild problem, so he’s been started on these as a first line measure: if they do not solve the problem, the more expensive ointment will be needed.
In advanced cases, the dryness of the eyes can be so severe that no ointment or drops is effective enough to help. Radical surgery by a specialist may be needed: one of the salivary glands is re-routed so that instead of its duct opening into the inside of the mouth, it opens into the inner eye. Saliva has similar lubricating properties to tears, and a dog is better able to cope with a dry mouth than with a dry eye.
There’s only problem with a re-routed salivary duct: dogs look as if they are crying before meals, because the sight of food when they’re hungry prompts a surge of saliva production into the eye.
Archie’s doing well on the tear drops,and Marie’s hoping that he’ll never need the complex surgery. He likes his food so much that he’d be crying all the time.
- Dry eye is a common cause of sore eyes, especially in some breeds
- Sometimes drops or ointment are enough to keep the eye comfortable
- Surgery involving re-routing the salivary duct is an extreme answer that’s sometimes needed