compound eye(redirected from Facet (anatomy))
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The eye of most insects and some crustaceans, which is composed of many light-sensitive elements, each having its own refractive system and each forming a portion of an image.
(Zoology) the convex eye of insects and some crustaceans, consisting of numerous separate light-sensitive units (ommatidia). See also ocellus
an eye, typical of insects, composed of many individual light-sensitive units that form a mosaic of images on the retina.
An eye, as of an insect or crustacean, consisting of hundreds or thousands of tiny light-sensitive parts, with each part creating a portion of an image.
Did You Know? The eyes have it—the important ability to see, that is. But not all eyes are created equal. Insects and other arthropods (which include lobsters and other crustaceans) have compound eyes, which are quite different from ours. The compound eye, greatly magnified, looks like a fencer's mask. It consists of many repeating units, called ommatidia, each of which is a separate light receptor. Some species' eyes have many ommatidia while others have only a few—the more ommatidia an eye has, the better it can resolve images. But even with many ommatidia, the typical compound eye is poor compared with ours at creating a sharp image. A honeybee, for example, sees only one-sixtieth as clearly as we do. However, the compound eye has other special talents. It is excellent at detecting motion, as the moving object passes from one ommatidium to the next. And some insects see ultraviolet light, which is invisible to us.