Cats Eyelids

Cats Eyelids

Cats eyelids are slightly different to human eyelids, as they have two per eye.

If you (or maybe your children) have either tried to open a sleeping cats eyes you may have noticed what looks like a second eyelid. This ‘third’ eyelid can range in colours and pigmentation, causing it to be quite dark to very pale pink, almost white looking.

The technical name for this extra eyelid is ‘palpebra tertia’, but is more commonly known as third eyelid, haw or sometimes as the nictitating membrane.

For each eye on a feline there is 3 eyelids, for a grand total of six eyelids. There is a horizontal top and bottom eyelids, which is always visible, and the third eyelid which moves at a slightly vertical angle in a cats eye. This third eyelid is rarely seen by humans.

What is a cats third eyelid made of?

A cats third eyelid or its ‘haw’ is just a fold of tissue with many membranes. For a more in depth answer here is an expert from Scientifica American;

“The anatomy of the third eyelid is complex. It is a fold of tissue covered by a specialized mucous membrane (the conjunctiva) that faces the inner surface of the eyelids (palpebral surface) on one side and the cornea on the other side (bulbar surface). Embedded in the bulbar surface is a dense population of lymphoid follicles that are in contact with the surface of the eye and the tear film, a thin layer of liquid. These structures function as the lymph nodes of the eye, trapping unwanted dirt and detritus.” – Veternarian Paul Miller  - Link

Why do cats have an extra eyelid?

The simplest answer is to retain moisture and prevent dirt disturbing the eye.

A cats third eyelid has an important job of aiding in producing tears which helps keep the eyes moist. They also sweep away any foreign objects on the eyelid, this reduces any irritation which debris may cause, similar to a car’s windshield wipers cleaning away any dust or dirt from view.

Signs of Sickness related to a Cats Eyelid

Some cats have a third eyelid which is always visible, some breeds such as Siamese cats are more prone to have protruding third eyelids. If your cat has had this its entire life there is usually no need to to be alarmed.

For most cats their third eyelid is rarely seen by humans, and when visible for an extended period of time can indicate that your cat is suffering from a health problem. A protruding eyelid can be an indicator of some common diseases including Haws syndrome and Horner's syndrome.   

Haws Syndrome

Haws syndrome is the most common reason for protrusion of the cat’s third eyelid. Haws syndrome is usually a symptom of an underlying health concern.

Cats that may be experiencing health problems (even as little as a cat cold) may show their third eyelids for an extended period of time.

This usually fixes itself as the illness is identified and is resolved.

For more information about Haws syndrome we recommend you read this online book for a in depth look at cat eye problems - Click Here.

Horner's Syndrome

Horner’s syndrome is when the eye appears sunken and red. It is a dysfunction of the sympathetic nervous system, which has multiple causes. Some causes include trauma, this is quite common when a cat has been hit by a car.

Something to bear in mind is Horner’s syndrome has been linked to cats after professional ear cleaning has been given, if your cat has recently had ad ear cleaning treatment done please be wary or this side effect.

For more information on Horner’s syndrome we recommend you read this online book for a in depth look at cat eye problems - Click Here.

Any sign of the third eyelid is reason to be concerned and more interested in your cat’s well being and to monitor your cats behavior and eating habits. If you feel your cat is acting different, sluggish or not eating your should take your cat to your local veterinarian straight away. Of course you can take your cat to the vets at the first sight of the third eyelid for peace of mind if you have the resources to do so.

Cat Health Guide 

You need to know this!!

This guide covers all common health problems associated with cats, learn more about cat eye problems now! Be an educated cat owner, it may just save your cats life one day.

This entry was posted in Cats.