The inability of the cat's nictitating membrane to retract is generally caused by Horner's syndrome caused by trauma, neurological injury, ear damage, idiopathic disease, and spinal cord tumors. You need to take the cat to the pet hospital to check the specific reasons. Treat in time to avoid affecting the cat’s health.
Tips:
The cat's nictitating membrane is generally used to protect the eyes from foreign objects, and will remove dust and other dirt on the surface of the eyeballs. Tears flowed from the corners of my eyes.