Abstract: A method of designing progressive addition lenses is provided in which the surface of the lens is in effect synthesized directly from its specification. A desired pattern of grid lines is produced in which the astigmatism is distributed over the entire pattern of grid lines in a predetermined manner, a standard grid viewing system from which rays are traced is then assumed, and surface normals for each grid crossing are calculated by using the grid object and grid image as known quantities and solving for each surface normal using the law of refraction and determining the surface of the lens from the respective surface normals.