Why are a cat's eyes covered with a film? - briefly
A cat’s eyes may appear covered with a film due to a condition called "third eyelid" or nictitating membrane, which can become visible when the cat is ill, dehydrated, or experiencing eye irritation.
Why are a cat's eyes covered with a film? - in detail
A cat’s eyes may appear to be covered with a film due to the presence of the nictitating membrane, also known as the third eyelid. This translucent or semi-transparent membrane is located in the inner corner of the eye and can sweep horizontally across the surface of the eye. Its primary function is to protect and moisten the eye while maintaining visibility. The nictitating membrane is a natural part of a cat’s anatomy and is present in many other animals, including birds and reptiles. It acts as an additional layer of defense against debris, dust, and potential injuries, especially during activities like hunting or exploring rough terrain. In normal circumstances, this membrane is not always visible, as it retracts when not in use. However, if it becomes more prominent or consistently visible, it could indicate an underlying health issue, such as an eye infection, injury, dehydration, or systemic illness. In such cases, it is essential to consult a veterinarian to determine the cause and ensure proper treatment. Additionally, certain breeds, such as Persians or other flat-faced cats, may have a more noticeable third eyelid due to their unique facial structure. Understanding the purpose of this membrane helps in recognizing when its appearance is a normal physiological response or a sign of a problem requiring attention.