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
Eye color symptomatic of liver diseases such as cirrhosis or hepatitis. A blue coloration of the sclera may also be symptomatic of disease. In general, any sudden changes in the color of the sclera should be addressed by a medical professional. Aniridia is a congenital condition characterized by an extremely underdeveloped iris, which appears absent on superficial examination. Normally, there is a thick layer of melanin on the back of the iris. Even people with the lightest blue eyes, with no melanin on the front of the iris at all, have dark brown coloration on the back of it, to prevent light