Why Is My Cat's Third Eyelid Showing?

Eyelids are there to keep the eyes moist so that they can function properly. They are necessary to protect eyes from injury, infection, and harmful ultraviolet rays. If you have ever stared deeply into your cat’s eyes, then you will know that they have one more eyelid than what you do. Humans only have an upper and lower eyelid while cats have a third eyelid located in the inner corner of each eye known as the nictitating membrane.

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Content:

1. Why Is My Cat's Third Eyelid Showing
2. Is Your Cat’s Third Eyelid Showing an Emergency
3. Third Eyelid Cat Home Treatment
4. Conclusion

Why Is My Cat's Third Eyelid Showing

Usually, the third eyelid of a cat should only peek out ever so slightly or only be visible briefly when waking up from a sleep or while your cat is yawning. The purpose of this third eyelid is to spread moisture evenly across the surface of the eye when the cat blinks or closes its eyes. This third eyelid also acts as an extra layer of protection.

“The third eyelid rotation associated with the nictitans gland prolapse and third eyelid cartilage eversion is a rarely encountered ocular disorder,” said Dr. Demir and Dr. Altundag in their research paper on the subject of cherry eyes in cats.

The third eyelid should not stay over, cover a portion of the eye when the eyes are open nor be clearly visible. There is a likelihood of a medical issue that needs to be assessed and treated by a veterinarian when this does occur.

Possible causes of a third eyelid showing:

• Conjunctivitis: this can be due to an irritation, bacterial or viral infection. The conjunctiva is reddened and often a discharge is seen to.
• Dehydration: the most common reason for cats to become dehydrated are due to kidney infection or failure, diabetes, liver disease or gastroenteritis. Many other illnesses could also be the cause of dehydration. Dehydration will cause the eyes to become dry and sunken in, which then often results in the third eyelid becoming visible. It is important to offer fresh running water, such as in a Water Fountain, to your cat as this tempts them to stay better hydrated.
• Corneal ulcer: when the outer layer of cells on the cornea is damaged this can cause an ulcer. These ulcers can be very painful and cause the third eyelid to become more prominent to protect the eye. These ulcers are most often caused by direct injury to the eye, such as from a cat fight.
• Pain: anything that may cause pain to, or around the eye can cause the third eyelid to become more visible. A few conditions that can cause this pain are uveitis, corneal ulcer, glaucoma, and even a growth behind the eye.
• Haws syndrome: a syndrome that causes the third eyelid of both eyes to start protruding. Vomiting and diarrhoea have been observed during the first few days of the protruding eyelids.
• Upper respiratory tract infections: this can cause swelling in the eye that may lead to a protruding third eyelid.
• Cherry eye: this is a condition that causes the lacrimal gland of the third eyelid to slide out of its place and form a bulge like a cherry at the corner of the eye. Cherry eyes are far more common in dogs but can also be seen in cats.

Dr. Fruchter says: “Haws syndrome occurs in generally healthy cats, with or without diarrhoea, and is characterised by a sympathetic neuropathy causing bilateral third eyelid protrusion and ptosis. Clinical signs are possibly triggered by contagious gastrointestinal pathogen(s) that presumably affect(s) the gut microbiota and influence(s) the gut‒brain axis.”

Is Your Cat’s Third Eyelid Showing an Emergency

If you only see your cat's third eyelid when they are busy waking up or yawning then no, that is not an emergency. You should only see the third eyelid for a few seconds at a time to be considered normal. If the third eyelid remains over the eye, or even partially over the eye for an extended period then that is cause for concern.

Your cat only has two eyes and just like in humans, they are sensitive organs and require immediate attention to prevent any serious or permanent damage. Sometimes other conditions can cause the third eyelid to protrude and not be eye related at all but will still require veterinary attention.

To determine the cause of the protrusion and what the necessary treatment will be, your veterinarian may perform a series of tests. All of this can add up very quickly, that is why it is important to have Emergency Fund for your pet. This way your budget will not limit your treatment options, and you will be able to do what is best for your furry friend.

Third Eyelid Cat Home Treatment

Under normal circumstances with a healthy cat the third eyelid should always retract almost instantly. If it remains out or protruding, please do not try any home remedies. There can be a serious problem, and you need to make an appointment with your local veterinarian to get the proper care and treatment your cat deserves. There are many conditions that can be the cause of the visible third eyelid and the only way to properly determine this is with a veterinarian. DO NOT EVER USE HUMAN MEDICATION FOR YOUR CAT. Human eye drops can cause more damage than what is already present. Only ever use feline friendly products that are available at your vet.

In the article on Management of Eye Protrusion in Cats with Acute Trauma Dr. Kanay says: “Preventing permanent vision loss and damage to the bulbus oculi in cases of proptosis, which is very important in small animal eye emergencies, and protecting the anatomical structures of the eye. Early intervention is important for protection.”

Conclusion

If left untreated permanent damage to the eye may occur and possibly to your cat’s overall health in the long run. It is not worth the risk, do what is best for your feline friend and take them to a veterinarian.