Why do cats' eyes turn green at night?

This should start with the role of the pupil, which is located in front of the lens and controls the intensity of light entering the lens, and changes with the intensity of external light. At night, the cat's pupil becomes larger, trying to receive more dim light, but because the lens and ciliary body converge, it is a convex lens, and the light is concentrated in a small range. It is precisely because the pupil becomes larger and the human photoreceptor cells are columnar cells at night, and the sensitivity is enhanced, so that it can be seen that it is changing. Cats have big eyes that can change. Its pupil can change shape several times a day, sometimes it is big and round, sometimes it is thin, and sometimes it looks like a jujube pit. Cat's activities are mostly at night and often lurk during the day, so its eyes have developed this physiological characteristic that can change with the brightness of light in order to meet the needs of life and activities. Especially at night, the big round pupils will glow. If you shine with a flashlight, the pupil will immediately become a thin line. The cat's eye, like many Nocturnal Animals, can adjust the amount of light and change quickly.

Why do cats' eyes change and glow at night?

It turns out that this is the interference phenomenon of reflective pigments. The reflective pigment layer exists behind the visual cell layer, which can reflect the light passing through the visual cell back, so that the light can be reused.