Meow! Because they’re naturally nocturnal animals (meaning they sleep during the day and are awake at night), cats are built to be able to see well even when there’s not a lot of light.
There are a few things that help cats to see so well in near-darkness. One of these things is that the iris (colored part) of cats’ eyes can open up very wide to let in a lot of light, so that even when there’s not a lot of light, they can let in as much of it as possible. Cats also have extra light-sensitive structures in the makeup of their eyes, especially as compared to animals like humans.
Additionally, cats have a special “mirror”-like layer in the back of their eyes. When there isn’t a lot of light in a room, this “mirror” reflects any light available back towards the front of the cat’s eyes. It’s almost like the cat gets to use the light twice! This helps the cat to see fairly well in a dark room!