MICROLENS ARRAYS IN THE ANIMAL KINGDOM

The compound eyes of insects and crustaceans are image-forming arrays of up to 30000 microlenses. There are basically two types of design. I n apposition eyes the overall erect image is made up from the centres of the small inverted images produced by each element in the array. Ho wever, in superposition eyes the ray paths from many elements combine optically to give a real erect image on the retina. The microlenses th emselves make use of both curved surface and graded refractive index o ptics, and in cer?ain crustacea the lenses are replaced by radial mirr ors or lens-mirror combinations.