Why Do Cats Roll Their Eyes When Sleeping?

Why Do Cats Squint with White Eyes While Sleeping?

When humans sleep and our eyes roll back, it's the white of our eyes that's visible. However, when cats squint with white eyes, it's their third eyelid, also known as the nictitating membrane, that's exposed. This membrane is usually tucked away within the eye socket, with only a small part visible at the inner corner of the eye. As cats rapidly move their eyes, the third eyelid can slowly shift from the inner to the outer corner, potentially covering the surface of the eye, creating a squinting appearance, which is more common during light sleep. Here are some reasons why cats might squint with white eyes while sleeping:

1. Instinctual Alertness. Cats, even when sleeping, maintain a high level of vigilance to avoid predators in the wild. They often keep one or two eyes open to detect any abnormalities and react swiftly. While pet owners may think their cats are safe at home, cats can still feel threatened in unfamiliar environments or when the household is noisy or when guests are over. In such cases, cats may slightly open their eyes while sleeping as a sign of unease about their surroundings.

2. Hunger. Cats may sleep restlessly when hungry, especially if they sense food nearby or if it's almost mealtime. They become more alert, ready to eat. This restlessness can lead to a slight squinting while sleeping. If they see their owner heading to the food storage, they'll rush to the food bowl or the owner's side. Some cats are particularly dependent on their owners, so their anxiety increases when they're not around. Even when dozing, they'll keep an eye on the owner's movements and may wake up immediately if they sense the owner is about to leave.

While it may seem unusual for cats to sleep with their eyes open, these situations are normal, and owners should not worry.

Additionally, cats squinting with white eyes could be due to eye issues, including visible nictitating membrane, eye injuries, or foreign objects in the eye.

1. Visible Nictitating Membrane. Normally, the nictitating membrane is visible when cats blink or sleep, but it retracts when they're awake. If the membrane remains visible consistently, it might indicate a health issue, possibly with the cat's eyes or nervous system, and a vet visit is recommended.

2. Eye Injuries. If a cat's eye is scratched or injured due to a collision, it may be forced to squint.

3. Foreign Objects in the Eye. If a cat's eye gets sand, stones, glass shards, or thorns, it can cause pain and ulcers, making it difficult for the cat to close its eyes while sleeping. Other conditions like corneal ulcers, third eyelid tears, or epilepsy can also prevent a cat from closing its eyes or cause them to keep them open due to pain.

These are some examples of why cats might squint with white eyes. If the squinting is temporary and the cat returns to normal shortly after, there's usually no cause for concern.