Ask the Vet - Third Eyelid

I just noticed a membrane covering the bottom portion of my 10-month-old cat’s eye. This was not visible before today, and she does not appear to be in any discomfort. What should I do?

What you are describing is called a “third eyelid.” It comes up from the bottom portion of the eye and covers part of the cornea. It occurs normally when cats are sleeping, but it can also occur as a protective mechanism if the eye is irritated or the cat is not feeling well (from a virus, for instance).

If the condition does not resolve quickly, or if she is showing any other signs such as sneezing, runny eyes, or increased sleeping/lethargy, a checkup is in order. Your veterinarian will examine her to look for fever, infections, or any other abnormalities. If it resolves on its own, just monitor for any recurrence.