Cats possess a unique eye structure. While their blinking might appear infrequent compared to humans, felines do indeed blink, and this seemingly simple action is fundamental to their ocular well-being and even their communication.
The Feline Blink
Cats utilize their upper and lower eyelids for blinking. Unlike humans, who blink around 15 to 20 times per minute, cats blink at a much lower rate, averaging about 4.1 times per minute. This reduced frequency is partly due to specialized adaptations in their eye anatomy. When a cat blinks, these primary eyelids move to cover the eye’s surface, distribute tear film, and clear away small particles.
Beyond the reflexive blink, cats also engage in a “slow blink,” a deliberate, gradual closing and opening of the eyes. This behavior is considered a sign of trust and affection, often referred to as a “cat kiss.” A slow blink signals contentment and safety in its environment. Conversely, rapid blinking or squinting can indicate discomfort, fear, or irritation.
The Third Eyelid’s Role
A distinctive feature of feline eyes is the nictitating membrane. This translucent, whitish-pink membrane is located in the inner corner of each eye, near the nose. It operates differently from the primary eyelids, often moving passively or reflexively rather than through voluntary control.
The third eyelid plays a significant role in maintaining eye health. It provides an additional layer of protection, shielding the eye from debris and injury. This membrane also assists in spreading tear film across the cornea, ensuring continuous lubrication and helping to remove irritants. Its presence allows cats to maintain eye moisture and protection without requiring frequent full blinks. In a healthy, alert cat, the third eyelid is typically not visible, retracting out of sight.
Why Blinking Matters for Cats
Blinking, encompassing the actions of both the primary and third eyelids, is integral to a cat’s eye health. It maintains proper lubrication by spreading tear film evenly, preventing dryness and discomfort. Blinking also serves a cleansing purpose, sweeping away dust, debris, and foreign particles. This constant clearing prevents irritation and damage, while providing defense against physical harm and supporting the eye’s immune defenses.
When to Be Concerned About Your Cat’s Eyes
While normal cat blinking is often subtle, certain changes in eye appearance or blinking patterns can signal a health issue. Excessive blinking, squinting, or holding one or both eyes partially or fully closed may indicate pain or irritation. A persistently visible third eyelid when the cat is awake and alert is also a common sign of an underlying problem, as it should normally be retracted. However, it is normal for the third eyelid to be temporarily visible when a cat is sleepy or recovering from anesthesia.
Additional signs that warrant veterinary attention include any discharge from the eyes, whether clear and watery, cloudy, yellowish, or green. Redness, swelling around the eyes, or a noticeable change in eye color or clarity are also concerns. If a cat frequently paws at its eyes, experiences pupils of different sizes, or shows signs of discomfort like bumping into objects due to impaired vision, a veterinary consultation is recommended. These symptoms can be associated with various conditions, including infections, injuries, allergies, or glaucoma.