Entropion is an uncomfortable or painful condition in which the animal’s eyelids roll inward, allowing the eyelashes (or other hair) to rub against the cornea and irritate it. The upper and/or lower eyelids can be involved, and the condition can occur in either one eye or both.

Signs
An animal with entropion will squint and have an excessive amount of tears coming from the affected eye. Some animals will be sensitive to light and will rub at their eyes, particularly when they’re outside. Some animals will produce a mucous-like discharge from the eyes. Flat-faced dog/cat breeds, with entropion that involves the inside corner of the eyes, may not show any discomfort -- simply because of their facial structure.

In some animals, entropion is never more than a minor annoyance, but in others it can cause painful ulcers and erosions that cause scarring and affect vision. That level of entropion needs surgical correction.

Causes
While any dog can have entropion, there is often a genetic factor. When caused by genetics, entropion can be seen well before a dog’s first birthday. Predisposed dog breeds include the Boxer, Bull Mastiff, Cavalier King Charles Spaniel, Chesapeake Bay Retriever, Chow Chow, Cocker Spaniel, English bulldog, Golden Retriever, Great Dane, Irish Setter, Irish Setter, Labrador Retriever, Poodle, Pug, Shar Pei, Springer Spaniel, and St. Bernard. Selective breeding for specific traits (e.g., skull formation, skin folds on the face, and prominent eyes) are thought to be contributing factors to genetic causes, but are most likely not the only genetic base. Selective breeding may have simply exaggerated entropion in breeds that were already prone to it.

Entropion can also occur as a secondary condition resulting from scarring of the eyelid, infection, corneal spasms and pain, trauma, or nerve damage. Sometimes it happens after the eyelids lose their normal neurologic function.

Diagnosis
Your veterinarian can diagnosis entropion through an ocular exam. A local anesthetic is usually used, to make the examination easier on the animal.

Because it’s important to determine whether or not there is a corneal ulcer secondary to the entropion, a fluorescein dye may also be used. The fluorescein will stick to damaged parts of the cornea, and show as a bright green area.

Treatment
Medical treatment with antibiotic ointments can decrease damage to the cornea, but it can not resolve the entropion itself. To fix the eyelid, surgery is needed.

Basic Do's and Dont's
If the entropion is significant enough to warrant treatment, the excess skin of the outer lids can be removed in a simple surgery called blepharoplasty. (Essentially, this is plastic surgery, so you can tell everyone your pet is having “his lids done”). Excess skin that causes skin folds is also removed, and the eyelids are tightened. Typically the entropion does not return after surgery, unless the case is quite severe.