A cat's pupils can change according to the intensity of light and its emotional state. In bright light, a cat's pupils constrict into a thin slit to reduce the amount of light entering and protect the retina from excessive light damage. In dim light, a cat's pupils dilate to a round shape to increase the amount of light entering the eye and improve night vision.
In addition, changes in a cat's pupils are also related to its emotional state. When a cat is excited, alert, or focused, its pupils dilate and become round to better observe its surroundings. Conversely, when a cat is relaxed or content, its pupils constrict, and its eyes become elongated.
