Eyes (also called eyes, eyes) are organs that can perceive light. The simplest eye structure can detect the brightness of the surrounding environment, and the more complex eye structure can provide vision. Compound eyes usually exist in arthropods (such as insects), and usually consist of many simple small eye surfaces, and produce one image (instead of multiple images as usually imagined).
In many vertebrates and some mollusks, the eyes image by projecting light to the photosensitive retina, where the light is received and converted into signals and transmitted to the brain through the optic nerve.