What causes a third eyelid to appear in a cat? - briefly
The appearance of a third eyelid in a cat is typically due to stress or illness. This nictitating membrane can be triggered by pain, fear, or infection.
What causes a third eyelid to appear in a cat? - in detail
The appearance of a third eyelid, also known as the nictitating membrane or haw, in cats is a response to various stimuli and can indicate underlying health issues. This protective structure is normally hidden in the inner corner of the eye, but when triggered, it slides across the eyeball to provide an additional layer of defense.
One common cause for the third eyelid to appear is stress or fear. Cats are sensitive creatures and can be easily startled by sudden noises, movements, or changes in their environment. When a cat feels threatened, its body releases hormones that activate the third eyelid as a protective measure. This response is similar to humans blinking rapidly when startled.
Infection or inflammation of the eye can also prompt the third eyelid to emerge. Conditions such as conjunctivitis, uveitis, or corneal ulcers may cause irritation and discomfort, leading the cat's body to deploy the nictitating membrane for added protection against potential harm. In some cases, the third eyelid may appear due to an allergic reaction or exposure to irritants like smoke, chemicals, or dust.
Dehydration is another factor that can cause the third eyelid to become visible. When a cat is not drinking enough water, its body may attempt to conserve moisture by reducing the production of tears. This decrease in tear volume can lead to dryness and irritation, prompting the third eyelid to slide across the eyeball for protection.
Moreover, certain medical conditions such as kidney disease or high blood pressure can affect the cat's overall health and cause the third eyelid to appear. These systemic issues may alter the fluid balance in the body or impact the functioning of organs related to eye health.
In some instances, the third eyelid may protrude due to neurological problems or injuries affecting the nerves that control its movement. Trauma to the head, brain, or spinal cord can disrupt these neural pathways and result in abnormal positioning of the nictitating membrane.
It is crucial for cat owners to observe their pets' eyes closely and note any changes in the appearance of the third eyelid. While occasional visibility may not be cause for concern, persistent or recurring protrusion warrants a veterinary examination. Early detection and proper treatment can prevent more serious health issues from developing.