Understand eye prescription symbols like SPH CYL Axis PD ADD and 6/6 so you can read test codes and choose the right lenses with more confidence
Learn what SPH eye prescription means, how to read positive and negative SPH values, and how they affect lens thickness, comfort, and clarity
Learn what eye test symbols like SPH, CYL, Axis, PD, ADD and Prism mean in your prescription and how they affect your glasses lenses before choosing new lenses