Why do cats show their inner eyelid when their eyes are open?

Introduction: The Curious Case of Inner Eyelids in Cats

Cats are fascinating creatures with many unique traits that set them apart from other animals. One of these traits is the presence of inner eyelids, also known as the nictitating membrane. This is a translucent third eyelid which is located in the inner corner of each eye and is often visible when the cat is awake and alert. Many cat owners wonder why their pets show their inner eyelids when their eyes are open. In this article, we will explore the anatomy of cats’ eyes, the function of the nictitating membrane, and its role in maintaining eye health.

Anatomy of Cats’ Eyes: Understanding the Third Eyelid

Cats have large, round eyes with a wide field of vision. They have three eyelids per eye, unlike humans who have only two. The nictitating membrane is the third eyelid in cats, which is made up of a thin layer of tissue called the conjunctiva. It is situated inside the inner corner of each eye and is attached to the lower lid. The nictitating membrane moves horizontally across the eye’s surface, covering the cornea, and then returns to its original position. The movement of the nictitating membrane is controlled by muscles that act independently of the other eyelids.