Abstract The SR‐IV refractor has a spherocylindrical optometer system which provides smoothly variable dioptric power of ±20.00 D sphere and ±8.00 D cylinder. A split‐field monitoring system and joy stick permit three‐dimensional alignment. A simultaneous‐view cross cylinder system provides distortion‐free side‐by‐side comparison of cross cylinder choices for cylinder axis and power refinement. Cross cylinder refinement incorporates automatic sphere compensation during cylinder power refinement and automatic selection of axis steps during axis refinement. A special astigmatic dial and ±0.50 D cross cylinders are provided for low vision refractions. Visual acuities are printed as well as the refined refractive findings at either spectacle or contact lens vertex distance.
David L. Guyton (Fri,) studied this question.