Impaired vision and blindness are common. About 3.4 million people in the US are blind or visually impaired. Vision is usually measured by visual acuity charts, and normal vision is expressed as 20/20 ...

Using the lamprey, researchers analyzed the photosensory mechanism of the pineal organ, also called the pineal gland, in non-mammalian vertebrates and discovered a novel mechanism of pineal color ...

Bold hues of red, orange, yellow, blue and purple help plants and animals communicate with their own species and others in their efforts to survive. Vivid orange dart frogs warn predators of their ...