What is entropion?
Entropion (en-TROH-pee-on) is an inward rolling of the eyelid which causes irritation and discomfort as the eyelashes and facial hair rub against the delicate cornea. Most cases involve the lower eyelid and can affect one (unilateral) or both (bilateral) eyes.
Unlike dogs, congenital (present at birth) entropion is rare in cats. It can be primary or secondary.
Anatomical defects, most commonly seen brachycephalic breeds Persian, Himalayan and Exotic which affects the inner portion of the eye (medial canthal entropion).
- Spastic entropion due to prolonged blepharospasm (abnormal contraction of the eyelid muscles) as a result of ocular pain (distichiasis, keratitis, conjunctivitis, corneal ulcers)
- Enophthalmos (posterior displacement of the globe) which develops due to loss of retrobulbar fat pad (the mass of fat contained in the orbit that contributes to the support of the eyeball)
- Acquired eyelid defects from injury, trauma, previous surgery or chronic inflammation, only one eye is usually involved in cats with acquired eyelid defects
Constant irritation from hairs rubbing on the sensitive cornea can lead to mucoid conjunctivitis, corneal ulcers, corneal sequestrum and corneal vascularisation (growth of new blood vessels in the cornea). Additional symptoms include squinting, eyelid spasm, photophobia (sensitivity to light), redness and rubbing the eyes.
In most cases, the veterinarian will be able to make a diagnosis based on clinical signs. A thorough ophthalmologic examination will be necessary to determine the underlying pathology.
- Fluorescein stain test to evaluate the cornea for ulcers, however, the stain is often not retained in cats with corneal sequestrum.
- Rose bengal stain is a sodium salt stain that binds with devitalised (dead) tissue in cats with corneal sequestrum.
- Slit-lamp biomicroscopy: An ocular examination using a slit-lamp, a microscope with a bright light which allows the veterinarian to examine the structures of the eye and will provide information on the depth of the sequestrum.
- Local anesthesia reverses spastic entropion, but not with anatomic entropion.
Untreated entropion is a constant source of pain and discomfort to the cat and can lead to corneal ulcers, corneal sequestrum.
Treatment of the underlying cause of secondary entropion should confer a positive result. This may include ocular antibiotics, artificial tears, lubricating ointments, soft contact lens (bandage lens) or tarsorrhaphy (a procedure in which the eyelids are temporarily sewn shut) to protect the damaged cornea.
Surgical correction for cats over 10-12 months (to allow for the cat to grow into the excess skin), where an underlying cause can or does not resolve the issue. This surgery is best performed by a veterinary ophthalmologist (a veterinarian who specialises in eye disorders). There are various surgical methods which include Y-to-Vcorrection, Hotz-Celsus (HC), lateral canthal closure, medial canthal V-plasty, and Stades method. Some cats will require more than one procedure.
One study of the surgical treatment of entropion in 124 cats found a success rate of 96% per eye.
Complications are rare but may include pain, and infection. Watch for discharge, weeping or oozing or redness and contact your veterinarian if you have any concerns.
The veterinarian will send the cat home with a discharge sheet and instructions on how to care for the cat post-surgery.
Do not let the cat outside and avoid strenuous exercise until the stitches have been removed. If you are having difficulty keeping the cat inactive (particularly younger cats), it may be necessary to temporarily confine him or her to one room of the house.
In most cases, the cat will need to wear an Elizabethan collar for a few days to prevent rubbing the eyes and damaging the surgery site.
Bathe the eyelids with a face cloth soaked in lukewarm water twice a day to keep the surgery site clean and free of discharge.
If the veterinarian has prescribed antibiotics, administer as prescribed.