(from the article `photoreception`) The large size of the camera-like vertebrate eye makes it potentially the most efficient of all eyes because it can project a large image on a large ... ...effectively; receptor and accessory structures constitute a sense organ. The eye of vertebrates is an organ of light reception (photoreception); .... Found on http://www.britannica.com/eb/a-z/p/61
A specialized cell type in a multicellular organism that is sensitive to light. This definition excludes single-celled organisms, but includes non-eye receptors, such as snake infra-red (heat) detectors or photosensitive pineal gland cells. See retinal rods, retinal cones.
Found on http://www.encyclo.co.uk/visitor-contributions.php