Human eye of the size of the pupil, regulation and suppression of the hormone melatonin and entrainment of the body clock. The eye is not shaped like a perfect sphere, rather it is a fused two-piece unit, composed of the anterior segment and the posterior segment. The anterior segment is made up of the cornea, iris and lens. The cornea is transparent and more curved, and is linked to the larger posterior segment, composed of the vitreous, retina, choroid and the outer white shell called the sclera. The cornea is typically about 11.5 mm (0.3 in) in diameter, and 1/2 mm (500
The Tribal Eye The Tribal Eye The Tribal Eye is a seven-part BBC documentary series on the subject of tribal art, written and presented by David Attenborough. It was first transmitted in 1975. This episode centers on the life and customs of the Dogon people in Mali, concentrating primarily on their masks and mask rituals. After a brief introduction to the Dogon culture, the link between African and European art is elaborated upon, using works by Picasso and Braque as examples. Dogon blacksmiths are shown working on a sculpture and a monkey mask for an old woman's funeral; the funeral rites, which include