Compound eye

arthropod eye
Dragonfly compound eyes
An image of a house fly compound eye surface by Scanning Electron microscope

Compound eyes consist of many photoreceptor units or ommatidia. Each 'ommatidium' (singular) is an individual 'eye unit'.

The image perceived is a combination of inputs from ommatidia on a convex surface. Thus they point in slightly different directions.

Compared with simple eyes, compound eyes possess a wide-angle view. They can detect fast movement and, in some cases, the polarization of light.[1]

The general pictureEdit

Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system.[2] Image-resolving eyes are present in molluscs, chordates and arthropods.[3]

Almost all insects and arachnids use both simple and compound eyes.

Types of compound eyeEdit

Compound eyes fall into two groups: apposition eyes, which form multiple inverted images, and superposition eyes, which form a single erect image.[4] Compound eyes are common in arthropods, and are also present in annelids and some bivalved molluscs.[5]

Compound eyes, in arthropods at least, grow at their margins by the addition of new ommatidia.[6]

Good fliersEdit

Good fliers like flies or honey bees, or prey-catching insects like praying mantis or dragonflies, have specialized zones of ommatidia organized into a foveal area which gives acute vision. In the acute zone the eyes are flattened and the facets larger. The flattening allows more ommatidia to receive light from a spot and therefore higher resolution.

Other typesEdit




  1. Völkel R; Eisner M. & Weible K.J. (2003). "Miniaturized imaging systems" (PDF). Microelectronic Engineering. 67-68 (1): 461–472. doi:10.1016/S0167-9317(03)00102-3.
  3. Frentiu, Francesca D. (2008). "A butterfly eye's view of birds". BioEssays. 30 (11–12): 1151–62. doi:10.1002/bies.20828. PMID 18937365. Unknown parameter |coauthors= ignored (|author= suggested) (help)
  5. Ritchie, Alexander (1985). "Ainiktozoon loganense Scourfield, a protochordate? from the Silurian of Scotland". Alcheringa. 9: 137. doi:10.1080/03115518508618961.