PURPOSE: To obtain a water glass, which can easily correct eyesight in water and can be manufactured at low cost, by supporting a transparent partition wall, which has uniform thickness and the curved surface of a prescribed curvature, to a frame.

CONSTITUTION: A transparent partition wall 2, which has uniform thickness land the curved surface of the prescribed curvature, is arranged in each frame 1. The partition wall 2 is formed in the shape of the curved surface and a prescribed incident angle is formed in incident light. Then, the incident light is effectively refracted. The refraction factor of water 4 and partition wall 2 is made enough smaller than the refraction factor of the partition wall 2 and air 6 by the relative difference of density and as a result, relation between an angle α1 and an angle α2 is α1>α2. Then, in the water, the light is refracted samely as a concave lens. Thus, even when a special optical system such as a lens, etc., is not used, the eyesight of a user can be corrected by using the water glass.