| 摘要 |
A subjective refraction technique uses a plane wave light source including substantially a point as a viewing target. The refraction method provide for a number of distinct identifiable end points. By finding such end points the process leads to an aberration-corrected vision. A defocus corrector assembly (DCA) includes a lens that is moveable along an optical axis between a patient's eye and the point light source for adjusting defocus power until the patient indicates that the blurry image has become a relatively focused line image. An astigmatism corrector assembly (ACA) which is capable of continuously variable in its amplitude is provided including a pair of astigmatism plates for adjusting astigmatism power and axis angle. The ACA is adjusted until the patient indicates that the line image has become a substantially round image. A reference marker provides displayed items including a sweep line overlapping at the point source and having an orientation which is adjustable. The patient may subjectively control the sweep angle of the sweep line and indicate that the sweep line is aligned with the sharp line image of the point source, thereby providing axis angle data of astigmatism errors of the patient's eye. |
