Cats have excellent night vision and can see at only a fraction of the light level required for human vision.
But even with their powerful night vision, cats cannot see in complete darkness.
No animal can see in the dark without at least a little light, however, cats have a distinct advantage on us in the dark.
For one thing, their pupils can expand three times wider than ours can.
Also, they have a layer of crystalline material behind their retinas that reflects light back out, giving their eyes a second chance to pick up images.
This layer, called the tapetum lucidum, is also the reason that cats’ eyes shine eerily at night when they catch a glint of light.
Unfortunately, what cats gain in night vision they lose in daytime sharpness.
While their eyes are perfectly suited to picking up movement, their overall vision is blurry, so much so that if something stops moving, the cat is likely to lose track of it.
Which is why you sometimes see cats watching television, but almost never catch them reading a book.