In addition to the upper and lower eyelids, your dog has a third eyelid located in the inner corner of the eye near the snout. Normally, this thin membrane is hidden and is barely visible in a healthy animal.
It glides quickly over the surface of the eye when necessary, then returns to its place. Unlike the other 2 eyelids, its movement is essentially passive and depends on the position of the eyeball.
This particularity is not specific to doggies. Many animals, such as cats, birds and reptiles, also have a nictitating membrane. In humans, only a small vestige remains located in the inner corner of the eye.
What is it for?
The nictitating membrane plays several essential roles in preserving the health of the eyes of Medor. Its first mission is to protect the cornea. In fact, it acts as a screen against dust, small debris or plants likely to injure the eye, particularly when walking in tall grass or undergrowth.
It also helps clean the ocular surface. As it moves, it helps eliminate impurities and evenly distributes the tear film.
In addition, this third eyelid contributes to the production of tears. A gland located at its base produces a significant part of the tear film, essential for keeping the eye moist, nourishing the cornea and limiting the risk of infections or irritation.
Finally, it constitutes an additional barrier against certain external agents, while promoting healing when the eye is slightly injured.
When to consult your veterinarian?
It is normal to briefly see the nictitating membrane when your faithful companion is sleeping, waking up or very tired. On the other hand, if it remains visible while he is awake, a consultation is strongly recommended.
A constantly visible third eyelid may be a sign of irritation, eye pain, dehydration, or a more general condition. Redness, swelling, discharge or excessive blinking should also alert you.
One of the most well-known problems is third eyelid gland prolapse. This gland moves out of its normal position and forms a red mass in the corner of the eye. Certain breeds, such as the English Bulldog, the Cocker Spaniel or the Beagle, are more predisposed to it.
If you notice a change in the appearance of your canine partner's nictitating membrane, avoid self-medication. Only a veterinary examination allows you to quickly identify the cause and implement the most appropriate treatment to preserve your dog's comfort.