Insect Vision

Thomas Shahan - Eye Arrangement of a Hogna Wolf Spider

What can insects and other arthropods see through their compound eyes?

Quick answer: they can see definite, resolved images. Some compound eyes yield a single erect image and others produce multiple inverted images. Their acuity is less than we can see with our single-lens vertebrate eye. Each optical cell in a compound eye can't form a very sharp image because the focal point always lies behind the retina.

But the view through compound eyes is not necessarily the super low-resolution hexagonal pixels or the kaleidoscopic multiplication effect that we've often seen in cartoony diagrams.

Arthropod eyes have certain advantages over our vertebrate single-lens eyes. They have a wider angle of view, infinite depth of field, fewer aberrations, and extreme sensitivity to motion. Their visual system operates within a tiny package, sometimes smaller than the head of a pin.

Most arthropods have not only the more familiar compound eyes, but also other kinds of optical sensors distributed on their bodies. These sensors may be specialized for perceiving light levels, movement, polarized light, expanded color vision, dim illumination, or heat signatures.

Eye structures vary among arthropods, a group that includes insects, spiders, crustaceans, and horseshoe crabs, plus extinct trilobites.

Engineers are working on artificial vision systems that enjoy the benefits of arthropod eye systems. They have been experimenting with imaging technology that delivers a full hemispheric field of view, using sensors crammed with hundreds or even thousands of individual imaging elements.