Sclera Sclera The sclera, also known as the white of the eye, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some elastic fiber. In humans, the whole sclera is white, contrasting with the coloured iris, but in other mammals the visible part of the sclera matches the colour of the iris, so the white part does not normally show. In the development of the embryo, the sclera is derived from the neural crest. In children, it is thinner and shows some of the underlying pigment, appearing slightly blue. In the elderly, fatty deposits on
Effect of spaceflight on the human body as with previous stations and spacecraft, and may not suffer from feelings of isolation in the same way. The sum of human experience has resulted in the accumulation of 58 solar years in space and a much better understanding of how the human body adapts. In the future, industrialisation of space and exploration of inner and outer planets will require humans to endure longer and longer periods in space. The majority of current data comes from missions of short duration and so some of the long-term physiological effects of living in space are still unknown. A round trip to Mars