Cylinder dioptometry.
D001251:Astigmatism / Q000175:diagnosis; D006801:Humans; D006956:Hyperopia / Q000175:diagnosis; D008722:Methods; D009216:Myopia / Q000175:diagnosis; D055095:Optics and Photonics; D012029:Refraction, Ocular / Q000295:instrumentation; D012030:Refractive Errors / Q000175:diagnosis*