But, it is not magic at all. It collects and re-emits light back to the retina a second time, giving the rods a second chance to absorb the image information, thus maximizing the little light available to them. As this light is reflected off the tapetum, the animal's eyes appear to glow. So, although nocturnal animals see mostly crude shapes, outlines and no color, by maximizing their sensitivity to low light levels with the above adaptations, it is enough for them to hunt, feed and survive in the dark of night. Most nocturnal animals are largely inactive during the day to avoid over-stimulating their highly sensitive eyes.
Nocturnal animals have specialized pupils to shut out damaging bright light.
Indeed, nocturnal animals dilate their pupils to their circular maximum at night. But by day, the circular pupil is inefficient at blocking light. Instead, a variety of pupil shapes have evolved that limit incoming light, the most advanced being the vertical slit. The slit pupil can shut out all light except a narrow band. Its vertical orientation is of significance too, as it works well with eyelids.