third eyelid (nictitating membrane) ragged or damaged

a cat I am fostering has a ragged edge to one of his 3rd eyelids. i don't know how long it's been like this since it doesn't protrude most of the time. it doesn't seem to bug him, his eyes are clear and bright and his behavior is frisky, but it definitely looks like the edge is a bit jagged, i can't tell if it's from an injury or if it's something else. anyone ever heard of this before?

I've had no experience with this, so I'm of no help. Maybe someone will come along soon to help you.

yeah it's an unusual issue, i've never heard of it before. tho it's odd it's not more common, seems like the 3rd eyelid could get damaged just like any other part of a cat, but now i'm wondering if it isn't just a sort of deformity. i'm taking him to the vet anyway so i'll see what the doc says.

I took him to the vet and the vet says it's either damaged from fighting or just like that from birth. He said it was unlikely to heal as a small piece is missing. but he said he's seen this before and it doesn't cause any problems, as long as the membrane is able to cover the eye normally and doesn't stick out. so he's okay!

one of my cats took a claw to the third eyelid last week and has a jagged tear to the nicitating membrane.  I've gotten the opinion of 3 vets and have decided to take a "wait and see" approach.  Meanwhile, I apply neomycin ophthalmic ointment in his eye twice a day.  he squints sometimes, but doesn't seem too bothered by the injury.  I refrain from tugging on the lower part of his eye to view the injury, as i do not want to disturb any healing.  Doctor said it is unlikely that the jagged edges will come together to heal, but that healing may occur to a degree.  

What ever became of your cat with regard to the torn eyelid?