Compound eye

The image perceived by this arthropod eye is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions.

[2] Because a compound eye is made up of a collection of ommatidia, each with its own lens, light will enter each ommatidium instead of using a single entrance point.

Long-bodied decapod crustaceans such as shrimp, prawns, crayfish and lobsters are alone in having reflecting superposition eyes, which also have a transparent gap but use corner mirrors instead of lenses.

Good fliers like flies or honey bees, or prey-catching insects like praying mantises or dragonflies, have specialized zones of ommatidia organized into a fovea area which gives acute vision.

One possible reason for this is that its environment is partly maze-like and consistently turning in one direction is a good way to search and exit mazes without getting lost.

[7] The body of Ophiomastix wendtii, a type of brittle star, was previously thought to be covered with ommatidia, turning its whole skin into a compound eye, but this has since been found to be erroneous; the system does not rely on lenses or image formation.

[8] "Dragonfly eyes" (Chinese: 蜻蜓眼 qingting yan) is a term for knobbly multi-coloured glass beads made in Western and Eastern Asia 2000–2500 years ago.