Insect eyes are are quite different from those of mammals, something that is obvious to anyone who ever really looked at them. Instead of having two big eyes they have hundreds or even thousands of tiny eyes, which form a "compound eye".

The individual eyes or "lenses" that make up the compound eyes are known as facets. Despite the common misconception that each facet forms a tiny but complete image, in reality each facet delivers a single spot, similar to the pixels on a computer screen. The insect brain then combines these pixels to form a complete picture. This is very similar to the way the image sensor (CCD) works in a digital camera.

When the compound eyes are seen at high power, as in the image to the right, they look like honeycomb. This is because the facets and the tissue around each facet form hexagonal (six sided) cells.