Each omatidea, or miniscule sensor, is directed at a slightly different angle from the others. Because of this, butterflies are able to see in virtually every direction simultaneously. There is a price to pay for having an exceedingly small brain and omnivision. Butterflies cannot focus their vision as what they see is at best a blur. Furthermore, they are sensitive to only the three most basic features of vision which would be light, color and motion.
Butterflies can distinguish night from day.
They might distinguish color along a very narrow band of the light spectrum. Hence a butterfly might see and feed from the nectar of a purple flower but be oblivious to the red flower nearby. Butterflies are also sensitive to movement. Butterflies do not have teeth or mandibles. Rather, their feeding mechanism is a long double barreled tube called a proboscis.