Q. What are compound eyes?
Arthropods have compound eyes made of several visual units called as ommatidia. Each ommatidium transmits visual information through the optic nerve to the brain which interprets the image. Because they are numerous and round, these ommatidia, whose external surfaces point in different directions creating independent images, cause arthropod eyes have a large visual field, larger than the visual field of vertebrates, a few insects have one or more simple eye besides their pair of compound eyes.