Entropion describes a condition where the eyelid "rolls in" on itself. It can affect one or both eyes, and the lower and/or upper eyelids. This condition is the opposite of Ectropion, where the lids sag and roll outward. Also see: Eyelash disorders of dogs and cats.
It is seen in both dogs and cats, though it is more common in dogs. Entropion can occur as a result of structural abnormalities of the eyelids, or secondary to other causes such as painful eye conditions (e.g. conjunctivitis).
It can be seen in any breed of dog or cat, but there is likely some genetic component to the structural causes of entropion. Dog breeds predisposed to entropion include Chow Chows, Shar-Peis, Mastiffs, Bull Mastiffs, Rottweilers, Great Danes, and St. Bernards, among others. In cats, Persians and other flat-faced breeds are predisposed.
Signs and Symptoms of Entropion
Entropion can cause severe irritation and injury to the eye — eyelashes and hair on the eyelids constantly rubbing on the surface of the eye are irritating and can cause damage to the cornea. Left untreated, entropion can eventually leading to scarring of the cornea and loss of vision.
Early or mild cases may cause eye discharge or excess tear production and blinking (called blepharospasm), squinting, and painful eyes (manifested by rubbing of the eyes). More severe or chronic cases can produce symptoms of conjunctivitis, keratitis, and corneal ulceration as well.
Diagnosis is usually straightforward, as the inward turning of the eyelid is usually apparent on exam. Further tests may be done to check that the inward rolling is not secondary to eye pain, and to check for injury to the cornea.
Treatment of Entropion
Entropion due to structural abnormalities usually requires surgery to correct the problem.
Eye ointment is often prescribed prior to surgery to treat irritation or damage caused by the entropion. In young animals, sutures (stitches) can be used to temporarily tack the eyelids in the "unrolled" position. In mild cases the temporary taking may be sufficient, but ultimately surgery is often required.
Tacking may need to be repeated to prevent irritation to the eye until corrective surgery is performed. Corrective surgery to reshape the eyelids is usually performed when the animal is more mature. Maturation of the involved structures reduces the chances of over- or under-correcting the condition. Multiple surgeries may be needed in severe cases.
In cases that occur secondary to pain from chronic conjunctivitis or other eye conditions, treating the underlying problem may resolve the entropion and should be attempted before surgical correction. Temporary tacking stitches may be necessary to prevent continuing irritation due to the entropion, however.