A Lab's Third Eyelid Suddenly Covering His Eyes
by A reader
When the third eyelid suddenly comes across the eye, it can look like the eyes are rolling back. One cause is Horner's syndrome, where the nerve supply to the eye is disrupted. That nerve runs from the brain down the neck and chest and back up to the eye, so injury or inflammation anywhere along that path, including the chest, can cause it. Other signs are a small pupil, a droopy upper lid, and a sunken-looking eye, usually on one side.
Third eyelids on both eyes coming up at once can also happen when a dog is very sleepy, unwell, dehydrated or has a tummy upset, and it often clears quickly, as it did here. Facial nerve paralysis (sometimes compared to Bell's palsy) is a different nerve and causes drooping of the face and trouble blinking.
Since he is back to normal, keep an eye out for it happening again, one-sided changes in his pupils or eyelids, a head tilt or loss of balance. Ask your vet to recheck him if it comes back, as they may look into the ear, neck and chest.
See neurological problems in dogs.
This is general information, not a diagnosis. Please follow your own vet's advice.
