(From to shut, and the eye). Short sight; dysopia dissitorum of Cullen; nuciositas, because the eyes are generally partly closed. This disease is owing to the excessive convexity of the crystalline, by which the rays, unless the object is placed close to the eye, are united before they reach the retina; consequently vision must be indistinct. This convexity may arise from a beginning hydroph-thalmia, or a too copious secretion of the aqueous humour; from a distention of the axis of the eye, in consequence of habit; from a natural (often an hereditary) convexity of the anterior curvature of the crystalline; from the density and, in consequence, the increased refractive power of the cornea. The increased convexity of the cornea is not uncommon in the infant state. The concavity of the spectacles must be proportioned to the sight, and myopes should begin with the least concave glasses. When they read they should never use them. See Amblyopia,and Oculus.