Laurie Anne Walden, DVM
Eyelid problems are common in dogs and cats. Some eyelid disorders cause damage to the eyeball itself and can affect vision. A pet with eye redness, eye drainage, eyelid swelling, an eyelid lump that is new or changing, or signs of eye discomfort (squinting, pawing at the eyes, rubbing the face) should see a veterinarian.
In dogs, most eyelid masses are benign tear gland tumors called meibomian gland adenomas. These masses are located along the lid margin and typically look like raised, bumpy, pink or dark brown lumps. Other types of benign tumors also occur in dogs and cats.
A chalazion is a firm lump caused by a blocked tear gland. This type of lump is near the lid margin under the skin, not right on the lid margin like a meibomian gland adenoma.
Benign eyelid masses can irritate the cornea (the clear structure at the front of the eye) and can enlarge over time. These masses are usually removed surgically. Removing an eyelid mass means removing part of the eyelid, so it’s best to do the procedure while the mass is still small.
Most eyelid masses in cats, and some in dogs, are malignant cancers. Many types of cancer affect the eyelids, just like the rest of the skin; some examples are squamous cell carcinoma, melanoma, and mast cell tumor.
The only way to know for sure if an eyelid lump is benign or malignant is to send it to a laboratory for analysis. If an eyelid mass is large or located near the inner corner of the eye, referral to a veterinary ophthalmologist is often the best option in case the patient needs reconstructive eyelid surgery.
The term cherry eye is an informal name for prolapse of the gland of the third eyelid. The third eyelid (nictitating membrane) is a pink structure at the inner corner of dogs’ and cats’ eyes. In animals with cherry eye, a tear gland protrudes out of its normal location behind the third eyelid; it looks like a smooth pink or red lump. Cherry eye is treated by surgically replacing the gland in its normal position. The prolapsed gland shouldn’t be removed entirely because it produces tears. Removal of the gland would put the animal at risk of dry eye (keratoconjunctivitis sicca).
Eyelid swelling could be caused by an allergic reaction, a benign or cancerous mass, inflammation, or infection. Eyelid swelling due to an allergic reaction is sudden and often affects both eyes. Because eyelid swelling is sometimes the first sign of a more serious reaction called anaphylaxis, it always warrants a call or visit to a veterinary clinic. An animal that has swollen eyelids along with other concerning symptoms like vomiting or wheezing should be taken immediately to an emergency clinic.
Entropion (Rolled-in Eyelids)
In animals with entropion, one or more eyelids are rolled inward so eyelashes and hair rub on the cornea. Entropion can be genetic or breed associated, especially in animals with loose facial skin and animals that are brachycephalic (short faced). The condition can also be caused by scarring, other eyelid disorders, or excessive squinting from eye discomfort. The damage to the cornea is uncomfortable at best and can eventually impair vision. Entropion is corrected with surgery. Young animals with entropion can sometimes be treated with a simple tacking procedure to help the eyelids roll back out to the normal position as they grow.
Occasionally hairs similar to eyelashes grow in the wrong location, either along the eyelid margin (distichia) or inside the eyelid (ectopic cilia). These hairs can cause significant pain and corneal ulcers. They’re hard to see and are typically found only with magnification during an ophthalmic examination to find out why an animal has a corneal ulcer. If they’re causing discomfort, the hairs and their follicles need to be removed.
Inflamed eyelids are red and swollen, sometimes with oozy discharge and visible sores along the margins. The hair on the eyelid might be thin or missing. Eyelid inflammation has many possible causes, including immune-mediated disease, parasites (like mange mites), bacterial or fungal infections, and irritants. Diagnosis might require skin scrapings, cultures, and biopsy. Treatment depends on the underlying cause.
You can see photos of some of these conditions on the American College of Veterinary Ophthalmologists website: https://www.acvo.org/common-conditions1
Image source: Hermes Rivera on Unsplash
Laurie Anne Walden, DVM
The contents of this blog are for information only and should not substitute for advice from a veterinarian who has examined the animal. All blog content is copyrighted by Mallard Creek Animal Hospital and may not be copied, reproduced, transmitted, or distributed without permission.