Minimum tangential error ophthalmic lens design without multi-parametric optimization

Conventional ophthalmic lens design is based on minimizing a merit function with the help of optimization algorithms. As an alternative to this design strategy, I present a novel procedure for ophthalmic lens design, which main feature is that geometrical properties of the lens surface - specifically sag, surface normals, and surface curvatures - are constructed point-by-point. To show the potentials of the procedure, I present some design examples of positive and negative lenses where the tangential power error is virtually eliminated for all gaze directions (up to 40°).