Slightly exposed third eyelids in cats may be caused by genetics, eye irritation, gastrointestinal discomfort, chronic parasitic diseases, fever, loss of appetite, or neck injuries. If a cat has an exposed third eyelid, It is necessary to observe whether the cat is in low spirits, loss of appetite, vomiting and diarrhea, etc. If so, it is best to send it to a pet hospital for examination and treatment.