A method for designing a spectacle lens that includes an optical convex
surface on an object side of the spectacle lens and an optical concave
surface on an eye side of the spectacle lens and is mounted in a
spectacle frame in a manner tilting with respect to a forward sight line,
the optical convex surface being spherical, the optical concave surface
being optically curved according to a prescription, the method including:
defining a design reference point at an intersection of the optical
concave surface and the forward sight line; and determining an angle
formed by a tangent line at the design reference point and a
perpendicular plane perpendicular to the forward sight line as a lens
tilt angle .theta. with which the spectacle lens is mounted in the
spectacle frame.