Patent ID: 7891812

Claim:
An opthalmologic instrument for measuring aberrations of a human eye, comprising: a point light source which is projected onto a retina of the eye to create a virtual light source thereon, wherein radiation of the virtual light source is scattered by the retina and then passes through optical systems of the eye and becomes phase-modulated, and wherein the modulation corresponds to a total of optical aberrations of the eye; a measuring system for measuring a shape of a wavefront of the radiation leaving the eye, and outputting an output signal to a control system of the instrument; a system for compensating for said aberrations, located between the eye and the measuring system and transmitting the radiation leaving the eye, wherein said system comprises a refraction compensator that controls focusing of the radiation scattered by the retina and an astigmatism compensator located at an image plane of a pupil of the eye, wherein the astigmatism compensator comprises: (i) one of two cylindrical lenses of opposite signs and two toric lenses of opposite signs, wherein said lenses are independently rotatable around an optical axis of the compensator, and (ii) a system for setting initial turning angles of said lenses; and a projector of test patterns, which, jointly with said refraction compensator and astigmatism compensator, projects an image of a test pattern onto the retina.