What is entropion?
Entropion is the inward rolling of the eyelid, most commonly the lower lid. This irritates the surface of the eye (the cornea) and may ultimately cause visual impairment.
Entropion is a common hereditary disorder in dogs. Selection for a particular conformation, of exaggerated facial features with prominent eyes and/or heavy facial folds, has created or worsened this problem in many breeds.
How is entropion inherited?
It is likely that ectropion is influenced by several genes (polygenic inheritance) that affect the skin and other structures that make up the eyelids, the way the skin covers the face and head, and the conformation of the skull.
What breeds are affected by entropion?
This problem occurs in many breeds. It is particularly severe in the mastiff, bullmastiff, Shar pei, and chow chow.
Entropion is seen in the Akita, Pekingese, bulldog, pomeranian, pug, Japanese chin, Shih tzu, Yorkshire terrier, Staffordshire bull terrier, dalmatian, old English sheepdog, rottweiler, Siberian husky, vizsla, weimaraner, toy and miniature poodle. It is also seen in hounds ( basset hound, bloodhound), spaniels ( Clumber spaniel, English and American cocker spaniel, English springer spaniel, English toy spaniel, Tibetan spaniel), and sporting breeds (Chesapeake Bay retriever, flat-coated retriever, golden retriever, Gordon setter, Irish setter, Labrador retriever).
Entropion is common in giant breeds such as the Great Dane, Bernese mountain dog, mastiff, Saint Bernard, Newfoundland, and Great Pyrenees. In these breeds the central lower lid is often ectropic while the lid at the corners of the eye is entropic.
For many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. We have listed breeds for which there is a consensus among those investigating in this field and among veterinary practitioners, that the condition is significant in this breed.
What does entropion mean to your dog & you?
The problem is usually evident before a year of age. Discomfort from entropion will cause increased tearing and squinting. Your dog may be sensitive to light and may rub at its eyes. Chronic irritation by the turned-in eyelid may cause corneal ulceration and scarring which is painful and, if not corrected, can impair vision.
Dogs who have had surgical correction for a defect such as entropion may not be exhibited in the show ring.
The inrolling of the eyelid is readily apparent. Generally both eyes are affected. Depending on the degree of corneal irritation and the duration, there will be other signs such as those mentioned above. Your veterinarian will evaluate the degree of entropion and use flourescein dye to determine if there is any corneal ulceration.
FOR THE VETERINARIAN: The use of topical ophthalmic anaesthetic to anaesthetize the cornea and conjunctiva will enable eliminatation of the spastic component of the entropion in order to better evaluate the anatomic component. This is important before surgery is performed.
How is entropion treated?
Entropion is corrected surgically. If possible it is best to delay surgery until the dog is an adult since the involved facial structures are still growing and changing.
More than 1 operation may be required. It is better to correct the entropion conservatively and repeat the operation later if necessary, than to overcorrect causing ectropion. In breeds such as the chow chow that have particularly severe entropion related to heavy facial folds, several surgeries may be required.
Entropion is one of the eye conditions that is a result of selection by breeders and a demand by the public for such features as excessively prominent eyes and heavy facial folds. A responsible breeding programme will choose animals for breeding with a more normal head conformation, so as to select away from these exaggerated facial features and the problems associated with them.