Cats Small Pupils. When your feline is about to pounce on your lap, shoulder, or at anything, you will notice that her pupils have dilated, reflecting excitement. Glaucoma is a condition in which increased pressure exists inside the eye.
When your cat has those perfect little cat eye slits, this is a telltale sign that they are happy and relaxed. When it is dark, the pupils are large (dilated), and when it is bright, the pupils are small (constricted). Glaucoma is another common cause for differing pupil size in cats.
