Number of Eyes on a Fly
How many eyes are there in a fly?
A fly has only 2 eyes which are compound eyes. A compound eye, although taken as a single sensory unit, consists of thousands of independent ommatidia, which are sensory columns having their own lens, cornea, and photoreceptor cells just like that of an single simple eye. Each ommatidium is responsible for delivering one pixel of an image to the fly brain.