Entropion describes a condition in which the eyelids roll inward causing the eyelashes to constantly rub on the sclera (white of the eye) and cornea (clear covering of the iris and pupil). This is most often a heritable trait found in purebred dogs; it is somewhat rare in cats but can occur. Entropion causes a significant amount of discomfort and irritation to the delicate tissue of the eye. Untreated, it can lead to a very painful ulceration, secondary infection, and ultimately sight-impairing scarring of the cornea. Symptomatic entropion almost always requires surgical correction. The procedure should be performed before symptoms become severe and damage to the eye becomes irreversible.
Because of its heritable nature, entropion usually causes the pet to become symptomatic at an early age. Acute onset in a mature animal is more likely to be secondary to injury or tumor formation, where scar tissue or cancer deforms the edge of the eyelid causing it to invert onto the eye. Since entropion may cause damage to the eye itself, the veterinarian will usually run several ophthalmic diagnostic tests during an eye exam even if entropion is visibly obvious. A flourescein stain uptake test is used to reveal corneal sloughing and ulceration which can quickly lead to vision loss if not treated aggressively. A Schirmer tear test may also be performed to make sure that tear production is not reduced which would impede healing.
The surgical treatment for entropion is called “blepharoplasty”. This procedure is performed under a general anesthetic. The affected eyelids are reshaped by removing excess skin above or below the eye. A small wedge is all that is usually required to roll the eyelid back to a normal position. A couple of sutures are placed to close the incision and will most likely be removed after 10 to 14 days. Any infection or irritation resulting from the entropion will be treated with topical ophthalmic medications that the owner will continue at home. Pets are sent home in an Elizabethan collar to prevent them from rubbing out the sutures or causing further self-trauma to the eyes.
If entropion is discovered in a very young animal, it may be possible to preclude blepharoplasty with a simple eyelid “tacking” procedure. Blepharoplasty is generally delayed until after 6 or 8 months of age, after the mature shape of the eyelid is fully realized. None-the-less, entropion should not go untreated, because damage to the cornea is very painful and can quickly progress to permanent vision loss.
There are numerous dog breeds that are predisposed to this condition, and dogs with a history of entropion should not be bred.