A Veterinary Ophthalmologist’s Perspective on Tear Staining
My clients often seek advice on how to treat the messy, frustrating problem of tear staining. If you research tear staining, you will find numerous different products, ideas, and suggestions that claim to fix or prevent the staining. The fact that there are so many products available means that there is not ONE magic treatment or approach that will work for every dog.
The red/brown discoloration in tears comes from porphyrin. Porphyrins are iron-containing molecules produced when the body breaks down iron. They are excreted through the gastrointestinal tract, urine, saliva, and TEARS! All dogs have some porphyrin in their tears, but some dogs have more porphyrin and the staining is always more noticeable in white or light colored dogs.
Common Causes of Tear Staining
A common misconception about tear staining is that it is due to excessive tear production. Most dogs with tear staining have normal tear production and do not have an underlying ocular problem. However, many dogs with tear staining have a normal variation in their eyelid conformation that causes tears to drain onto their face rather than draining down the nasolacrimal puncta and into the nasolacrimal system. The nasolacrimal system normally drains tears from the orbit into the mouth and nose.
There are three common variations in eyelid conformation that cause tears to spill onto the face rather than drain through the nasolacrimal system.
- Tight medial canthal ligament: The medial canthal (palpebral) ligament is tighter in some dogs which causes the medial portion of the eyelids to roll slightly inward. This creates a partial, functionally, obstructed nasolacrimal puncta which then causes tears to spill over onto the face.
- Haired lacrimal caruncle: The lacrimal caruncle is a triangular prominence in the medial canthus which normally has fine hair and a few sebaceous glands. Some dogs have longer hair. This hair then wicks tears onto the face bypassing the nasolacrimal puncta.
- Medial canthal troughing: Medial canthal troughing occurs when the skin at the medial canthus forms with a widened trough-like triangular area which funnels tears onto the face, again avoiding the nasolacrimal puncta.
A medial canthoplasty is a surgical option to reduce tear staining in some dogs with these types of normal eyelid conformations. Cryotherapy can be used to treat a haired lacrimal caruncle. However, in most dogs neither procedure is warranted. Any ocular irritation in a dog with any of these variations in eyelid conformation will cause more than the typical tear staining. Allergies, teething, corneal ulcer, or other ocular disease may also be the culprit.
Treating Tear Staining Starts with Grooming
Step one in treating tear staining is keeping the hair around the eyes and nose as short as possible. The next step is to keep the face clean and dry. A warm washcloth and baby shampoo are safe to use to clean around the eyes. There are many types of eyelid and eyelash cleaning pads that can also be used to clean the face and around the eyes. Contact lens solution containing boric acid can be used to clean around the eyes but not in the eyes as the boric acid in the contact lens solution oxidizes the iron in the porphyrins and may lighten the staining. After washing the face, always dry the area with a clean towel to prevent irritation or infection secondary to the wet skin.
A Note about Tylosin-containing Products
Tylosin-containing products claim to treat or prevent tear staining. However, tylosin’s effect is unpredictable and often has intermittent efficacy. Because tylosin is an antibiotic, there is controversy using it for cosmesis due to possible drug resistance. There is also controversy regarding tylosin’s addition to over-the-counter medications that do not always list it as an
ingredient or identify how much tylosin is in the product. Many probiotic supplements claim to decrease tear staining as well.
A Veterinary Ophthalmologist Can Help
Dog’s with tear staining should be evaluated to rule out an underlying ophthalmic problem that requires specific treatment. If the tear staining is secondary to conformation, the treatment plan should be an educational discussion focusing on proper cleaning and grooming. Referral to an ophthalmologist is appropriate to rule out underlying ocular disease and to discuss the possible surgical options, as appropriate.
Vanessa J. Kuonen Cavens, DVM, MS, Diplomate, ACVO is a Veterinary Ophthalmologist at MedVet Cincinnati and MedVet Dayton. She has been on staff at MedVet since 2008. Dr. Kuonen Cavens attended Brigham Young University where she earned a Bachelor of Science degree and Kansas State University where she earned both a Masters of Science and Doctor of Veterinary Medicine degrees. Following her graduation from veterinary school, Dr. Kuonen Cavens completed a yearlong internship in small animal medicine and surgery, a three-year residency in ophthalmology, and earned a Masters of Science at The Ohio State University College of Veterinary Medicine.
In 2004, Dr. Kuonen Cavens was awarded the American College of Veterinary Ophthalmologists Foundation research grant award for her work, “The long-term effects of semiconductor diode laser transscleral cyclophotocoagulation on the normal equine eye and intraocular pressure”.
Since becoming a board-certified Diplomate of the American College of Veterinary Ophthalmologists, Dr. Kuonen Cavens has become a leader in the veterinary community. She is the author and co-author of scientific articles published internationally in peer-reviewed journals, including Veterinary Ophthalmology and Investigative Ophthalmology & Visual Science. She is an active advocate of continued education for veterinary professionals and has lectured on various small animal veterinary ophthalmology topics at the Midwest Veterinary Conference, Annual Kentucky Veterinary Medical Association Meeting, North Carolina Academy of Small Animal Medicine, Annual Morehead Clinic Days Veterinary Conference, and the Northern Kentucky Veterinary Medical Association Meeting.
Dr. Kuonen Cavens maintains an interest in all aspects of small animal ophthalmology with particular interests in cataract surgery, corneal Surgery, eyelid reconstruction, tear film and ocular surface disease. In her practice of ophthalmology, Dr. Kuonen Cavens maintains an emphasis on communication and enjoys educating clients and veterinarians on the options available to restore and maintain vision in animals.
In addition to her work at MedVet, Dr. Kuonen Cavens volunteers through the ACVO and the Cincinnati Veterinary Medical Association, to provide ocular examinations for service/therapy dogs and police dogs. She also volunteers her time to treat patients at the Raptor Rescue and Cincinnati Zoo. When not treating patients, Dr. Kuonen Cavens enjoys spending time with her husband, son, and Great Dane, Cosmo.