The prolapsed third eyelid gland is visible as a pink mass or ‘lump’ near the inner corner of the eye and resembles a cherry, hence the common term ’cherry eye’.
Why Do Dogs Have A Third Eyelid?
The nictitating or third eyelid is critical for a healthy eye. It functions to:
Produce a third of a dog’s tears. The membrane has a tear-producing gland that is necessary to keep the exposed eyeball lubricated. They also provide essential oxygen and nutrients to the eye’s surface. Some dogs, particularly toy breeds such as the Maltese and Yorkshire, have a problem with tears leaking down their face instead of draining away in tear ducts. This causes unsightly tear stains, most noticeable on light-colored fur. Dog eye wipes with tear stain remover are necessary to dry the area around the eyes and prevent red tear stains.
By sliding across the eye, the third eyelid acts like a windscreen wiper, wiping away dust, pollen, or any other substance that can irritate the eyes. It also has a slimy underside that moisturizes the eyeball and spreads the tears evenly across the surface to prevent dry eye.
The third eyelid also protects the cornea, so it is vital to prevent painful corneal ulcers.
So the third eyelid is a vital part of a dog’s anatomy. But what kind of problems may arise with it?
How Many Eyelids Do Dogs Have?
Here is where dogs and humans differ. Dogs have three eyelids while humans only have two functional eyelids.
A dog’s third eyelid—also called the nictitating membrane—is usually hidden, with only a small portion normally visible. If you look closely into your dog’s eyes, you will see a small triangular segment of his third eyelid at the inner corner of his eyes. The third eyelid is typically black, brown, or (rarely) pink.
Dog Eyelids – How Many Eyelids Do Dogs Have? (Dog third eyelid)