Abstract: Apparatus for measuring the refractive powers of a lens and displaying the measured powers in so-called prescription form. A focimeter is equipped with means for generating electrical signals indicative of the net refractive powers of the lens, which signals are extended to novel electronic logic and control means for ultimately reading out and/or displaying the lens powers in a prescription form having "sphere" and "cylinder" components of power. Selectively activable control means determine whether the prescription is displayed in so-called "+ cylinder" notation or "- cylinder" notation. Additional means are provided for indicating which of two possible axis angles is correctly associated with the particular displayed component of cylinder power.