Reid considers it to be the effect of inflammation in the nictitating membrane
. When the animal was alive I placed my finger within half an inch of its head, and not the slightest notice was taken: it made its way, however, about the room nearly as well as the others.
In South America, a burrowing rodent, the tuco-tuco, or Ctenomys, is even more subterranean in its habits than the mole; and I was assured by a Spaniard, who had often caught them, that they were frequently blind; one which I kept alive was certainly in this condition, the cause, as appeared on dissection, having been inflammation of the nictitating membrane
. As frequent inflammation of the eyes must be injurious to any animal, and as eyes are certainly not indispensable to animals with subterranean habits, a reduction in their size with the adhesion of the eyelids and growth of fur over them, might in such case be an advantage; and if so, natural selection would constantly aid the effects of disuse.
Corneoscleral junctions are affected most frequently but involvement of eyelids, conjunctiva and nictitating membrane
is also reported in some cases (Perino et al., 1993).
They all have a nictitating membrane
-- that creepy third eyelid.
Beavers also have a third, transparent eyelid (called a nictitating membrane
) that protects their eyes as they swim underwater.
When the retractor bulbi muscle contracts, the nictitating membrane
(third eyelid) is closed as a protective mechanism (Fig.
To prevent this, a nictitating membrane
, sometimes referred to as a bird's "third eyelid," closes an instant before impact, keeping the eyes securely in their sockets and preventing any wood chips from damaging the eyes.
Caution was taken to avoid overapplication or contact with the eyelids or nictitating membrane
. Recovery and postoperative care was similar to previous procedures, with the addition of butorphanol tartrate (1 mg/kg IM q12h, for 1 day) to the analgesic protocol.
The nictitating membrane
is found on which part of animal's body?
I've never been happier to see a working nictitating membrane
Gharagozlou (2007) studied the natural occurrence of ocular neoplasms in dairy cattle and reported that mostly the lesion were located in the nictitating membrane
and palpebral conjunctiva and the tumors were squamous cell carcinoma, lymphosarcoma and malignant heman-gioendothelioma.
The third eyelid is also known as the "nictitating membrane
." The purpose of the third eyelid is to further protect and lubricate the eye.