My cat’s two pupils look different sizes—I’m afraid it will go blind

From the photo, the cat’s two pupils differ in size. The pupil is the elliptical opening in the iris; normally both dilate and contract together with light. Unequal pupils likely signal an eye or underlying disease.

Possible causes: corneal injury, corneal ulcer, nerve damage (Horner’s syndrome), glaucoma, uveitis, retinal disease, iris atrophy, congenital iris defect, tumors, spastic pupil syndrome, FIV, toxoplasmosis.

A white spot below the right pupil suggests right-eye corneal injury and conjunctivitis as the main suspect. Sudden anisocoria needs urgent veterinary care to avoid permanent vision loss; the vet will review history, examine the eye, and plan treatment.