Bear Watching and Tear Staining

I'm back from my camping trip in Montana. I had a great time watching bears up in Glacier National Park. It's a great time to be up there with very few tourists and lots of opportunities to see wildlife.

I got a chance to speak with my financial adviser on my drive home. My conversation with him involved the irony of my watching bears in Montana while they simultaneously wreaked havoc on Wall Street.

I also got to use my vet skills just south of Monticello Utah where I helped a rancher and a San Jaun County Sheriff herd some rogue cattle off US Highway 191 back to safer pastures.

When I got back to my office I had a question about the brown stains that some dogs and even some cats get below the corners of their eyes. This can be a real issue for owners of white dogs like Bishons, Maltese, Poodles and even Persian cats.

To answer this question you have to know a little about anatomy. We constantly produce tears to lubricate and protect our eyes. The excess tears are carried away via a drainage system called the naso lacrimal ducts. As the name implies these tubes go from the eyes to the inside of the nose. If you ever wondered why your nose runs when you cry you have an understanding of how these ducts work.

Normal tears are clear and colorless. The tears themselves don't cause brown stains. The staining results from the interaction between tears and bacteria and even yeast that normally inhabit the healthy skin of dogs and cats. This reaction turns the white or light colored hair brown and is very obvious on white dogs.

There are a number of anatomical causes involving the eyelids and eyelashes. Dogs with ectropion or droopy eyelids as well as dogs with entropion where the lid is turned in to the eye can be afflicted.

For these dogs there are surgical procedures that can correct the lid defect and result in much improved drainage.

Sometimes, the naso lacrimal ducts themselves are blocked. In some cases the ducts can be flushed by a veterinarian and normal drainage is restored. The ducts can even be blocked by foreign bodies like grass awns and of course eye infections and allergies can all contribute to poor drainage and excessive tearing. Dogs with infections or foreign bodies often have red irritated eyes and if you treat the original problem the eyes will clear up and the drainage will return to normal.

Dogs with clear eyes and brown stains usually have some problem related to genetics that result in slow or poor drainage of normal tear production. Sometimes the hair around the eyes acts as a wick that funnels tears away from the normal drainage path.

In some dogs there is no obvious surgical correction and no obvious infection to treat. There are a number of recommendations for how to handle these dogs involving antibiotics, diet change and others. I'm not convinced that these "cures" are supportable by sound research and often seem to be an unscientific shot gun approach to treatment.

In some dogs there isn't a real great solution other than keeping the eyes clean and making sure that the ducts are working as well as they can. That can mean that you simply have to live with a little brown discoloration.

And compared to the state of the economy that's not a real killer.

Comments

[Lindsay]

My cat has these "tear stains." I guess I never saw it as a medical condition. I just try to keep his eyes clean. I'll ask his vet about it next time I see her just to make sure she thinks everything is normal.