COMPACT SUBJECTIVE REFRACTIVE INSTRUMENT

摘要

A compact ophthalmic instrument for refraction of patient's eyes is obtained by substantial folding of the optical system. The optical system is folded in one location using a reflection means that moves to vary the location of a target image being viewed by a patient for identifying the spherical power of a corrective lens, if any, required by the patient. A second folded portion of the optical system contains a cylinder means for cylindrically varying the target image.