The sclère , or sclerotic is a white and opaque membrane, very resistant of tendineuse structure and thickness from 1 to 2 mm which form the “white” of the eye. It makes it possible to contain the internal pressure and to protect it from it from the mechanical aggressions. The sclerotic form almost four fifths of the surface of the Eye-ball. Behind, it is crossed by the Optical nerve and laterally, by openings intended for the vessels and the nerves. In its former part, the sclerotic one is covered with the Conjonctive (fine mucous membrane which recovers also the inner face of the Paupière S, making them thus interdependent of the eye and is prolonged by the Cornée.