Answer to identifying an eye condition

Photo courtesy of Alex Sigmund, DVM, DACVO

Entropion is a condition where the eyelid rolls inward, causing the periocular hair to rub against the cornea. It can affect any aspect of the upper or lower eyelids, but the lower, lateral aspect is most commonly affected. This constant friction leads to irritation and discomfort, and, if left untreated, can result in tearing, keratitis, and corneal ulcers.

Although it may seem minor, entropion can severely impact a pet’s quality of life, causing pain and potential vision loss if ulcers worsen. Factors that affect the risk of entropion include eyelid fissure length, skull conformation, orbital anatomy, gender, and periocular facial folds.

Common symptoms of entropion include:

• Excessive tearing, especially from the lower lateral eyelid.
• Chronic corneal ulceration, especially on the lower, lateral cornea.
• Squinting or blinking
• Eye redness and inflammation
• Rubbing at the eyes

There are 4 types of entropion. They are as follows:

Conformational entropion

This is the most common form and often affects breeds with specific facial structures and tissue development rates. Rottweilers, Great Danes, Mastiffs, and Labradors are a few common canine breeds. Persians, Maine coons, and domestic shorthairs are a few common feline breeds. Brachycephalic breeds commonly have medial entropion from facial folds. A polygenic inheritance is suspected with no identified genetic mutations for screening purposes.

Depending on breed, occurrence can occur at 4 to 7 months of age, but breeds such as the Shar-Pei and Chow Chow can have entropion as early as 2 to 6 weeks of age. Temporary tacking sutures or hyaluronic acid-based fillers can be used in young patients to allow them grow into their features. If closer to 6-12 months, then surgical intervention is likely needed.

Spastic entropion

This type of entropion occurs secondary to discomfort that can occur from severe conjunctivitis and corneal ulcers. With corneal pain, the eye becomes enophthalmic which allows the eyelids to roll inward and contact the eye which worsens the squinting and the entropion. Applying a topical anesthetic can temporarily eliminate the cause of discomfort and allow the eye’s position to relax to help diagnose this condition. If the entropion resolves, then a surgical option is not necessarily needed and a temporary procedure is needed, such as tacking sutures.

Cicatricial entropion

This form of entropion occurs from scar tissue from trauma. This trauma can be physical, such as an eyelid laceration, but it can also be from chronic, painful ocular disease, such as herpetic conjunctivitis especially in cats. Treatment commonly involves surgery.

Involutional entropion

The last form of entropion occurs from loss of orbital tissue (both muscle and fat). This can occur from aging, severe weight loss, hyperthyroidism, and neurogenic muscle atrophy. There is no reliable treatment for restoring orbital tissue mass, so surgically addressing the entropion is usually needed. Unfortunately, entropion can recur due to continued loss of orbital tissue. Hyaluronic acid-based filler agents can be used as a temporary nonsurgical route to address mild to moderate entropion.