They have black and white stripes, theoretically if a lion (which is colorblind) is looking at a zebra in tall grass it may not see it due to the stripe formation.
Zebras have excellent eyesight. It is believed that they can see in color. Like most ungulates the zebra has its eyes on the sides of its head, giving it a wide field of view. Zebras also have night vision, although not as advanced as that of most of their predators, but their hearing compensates.