There is a third eyelid for a keen sense of vision.

There should not be the appearance of haw or a third eyelid.

They can also experience cherry eye, a prolapsed third eyelid.

His eyes were half clouded with the third eyelid.

There is also a third eyelid on each eye, the nictitating membrane.

It also has a clear third eyelid which is thought to act like a pair of goggles underwater.

The third eyelid covered nearly half of the eye and, when the old man pulled down the dog's eyelids, he saw that they were pale.

The eyes are very large and lack nictating membranes (protective third eyelids).

A test now available which is performed by sampling a small amount of lymphatic tissue from the third eyelid.

The wings are opened under water and the open eyes are protected by the transparent third eyelid.

The eyes are large and oval, with a nictitating membrane (a protective third eyelid).

If a cat chronically shows the third eyelid, it should be taken to a veterinarian for evaluation.

The moderately large, circular eyes are equipped with nictitating membranes (protective third eyelids).

His third eyelid closed, then his fourth.

In veterinary medicine, signs can include partial closure of the third eyelid, or nictitating membrane.

Unlike humans, horses also have a third eyelid (nictitating membrane) to protect the cornea.

If sand gets lodged in their eyes, they can dislodge it using their transparent third eyelid.

Instead the eye is lubricated by the nictitating membrane, a third eyelid that moves horizontally.

Ulcers in the inferior nasal cornea may be caused by foreign material trapped under the third eyelid.

The cherry eye is due to a gland called the gland of the third eyelid, which prolapses.

"Dogs have a third eyelid.

The small, horizontal eyes are placed rather high on the head, and equipped with rudimentary nictitating membranes (protective third eyelids).

Ophthalmic signs may include third eyelid protrusion, red eyes, and exophthalmos (protruding eyeballs).

In many species, the third eyelid plays an essential role in vision by supplying oxygen and nutrients to the eye via tear production.

The Calabar angwantibo is the only primate to have a functioning nictitating membrane (third eyelid).