There are A LOT of differences! To name a few...
Cats see vivid colors, and a wider range than dogs. (It is said dogs only see in black, white and possibly green)
Cats have the largest eyes of any carnivore. In comparison to a dog, their eyes are much, much larger and able to see more at once.
The dilation is also different in dogs and cats. Cats can change this at will, no matter light or dark. This helps them focus on objects far away.