Entropion in Cats
Entropion is a genetic condition in which a portion of the eyelid is inverted or folded inward against the eyeball. This results in irritation and scratches to the cornea -- the front surface of the eye -- leading to corneal ulceration, or corneal perforation. It can also leave dark-colored scar tissue to build up over the wound (pigmentary keratitis). These factors may cause a loss or decrease in vision.
Generally, only brachycephalic breeds of cats, such as Persians, are at risk. Entropion is almost always diagnosed around the time a cat reaches its second year of age.
Symptoms and Types
Common symptoms usually include excess tearing (epiphora) and/or inner eye inflammation (keratitis). The eye may be visibly red, or the skin around the eye socket may be sagging. In some cases mucus and/or pus discharge from the outer corner of the eyes will be apparent, signaling a possible infection.
Facial shape is the primary genetic cause of entropion in cats. In short-nosed, brachycephalic breeds there is more tension on the ligaments of the inner eye than normal. This, along with the conformation of their nose and face, can lead to both the top and bottom eyelids turning inward toward the eyeball.
Large breeds have the opposite problem. They tend to have excess slack in the ligaments around the outer corners of their eyes. This permits the outer edges of the eyelids to fold inward.
Repeated bouts of conjunctivitis can cause spastic entropion, which can lead to functional entropion. This can also be caused by other types of eye irritants and is generally the case in cats that do not normally exhibit entropion.
Diagnosis of entropion is fairly straightforward through examination and any underlying causes or irritants should be dealt with prior to attempting surgical correction. Breeders of cats that are prone to this condition should pay close attention to kittens, having them checked for entropion if their eyelids do not open by four or five weeks old.