nictitating membrane (3rd eyelid)

vince

TCS Member
Thread starter
Super Cat
Joined
Jul 23, 2017
Messages
1,193
Purraise
1,863
Location
metro Detroit
I was looking at my dozing cat, and as he slowly closed his eyes, I could see his third eyelid slide over as the eyes closed. I was wondering if anybody knows if the third eyelid always closes when the eyes are shut, and can the cat extend the third eyelid at will?
 

fionasmom

TCS Member
Staff Member
Forum Helper
Joined
Jun 21, 2014
Messages
5,341
Purraise
7,724
Location
Los Angeles
My vet once said that the third eyelid is passive but that in some circumstances the cat may have some control over it. However, those circumstances were irritation or injury to the eye, or another condition which might have arisen. If you continue to see it, I would check with the vet.
 
  • Thread Starter Thread Starter
  • #4

vince

TCS Member
Thread starter
Super Cat
Joined
Jul 23, 2017
Messages
1,193
Purraise
1,863
Location
metro Detroit
I don't think it's any problem. As he was nodding off and slowly closing his eyes, I saw it slide over just as the eye was a little slit before the eyelid closed completely. He seems to be fine.
 

kittenmittens84

TCS Member
Alpha Cat
Joined
Sep 30, 2019
Messages
615
Purraise
595
So when cats sleep and their third eyelid slides across their eye, I think it’s actually because the muscles behind their eyeball are retracting the eye into the socket, which in turn passively pulls the third eyelid across. Cats who are very dehydrated can have “sunken” looking eyes which can also lead to the third eyelid showing, since again the eyeballs are retracted farther than normal.
 
Top