Aberrometer provided with a visual acuity testing system
An aberrometer is provided for automatically measuring a human eye aberration, determining a subjective visual acuity associated with the selection of a best spherocylindrical correction, and investigating the influence of high orders aberrations on the visual acuity. The aberrometer includes a point light source which is projected on the eye retina, scattered back by the retina, and passes through the eye optical systems acquiring a phase modulation corresponding to the total eye optical aberration. The aberrometer also includes a wave front sensor whose output signal is transmitted to a device control system, an aberration compensation system which is disposed between the human eye and the wave front sensor and through which radiation coming out from the eye and projected on the eye retina passes, and a test picture projector which projects the test picture image on the eye retina through the aberration compensation system.
1. 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.
2. The instrument of claim 1 , wherein the refraction compensator comprises a movable prism and a dichroic mirror which are placed between two lenses, and wherein said dichroic mirror is operable as a beam-splitter to align the instrument.
3. The instrument of claim 1 , further comprising a built-in automatic calibration system which uses an additional virtual light source as a test element to measure current positions of the compensators.
4. The instrument of claim 1 , further comprising an alignment system which adjusts a proper distance between the eye and the instrument.
5. 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, an astigmatism compensator located at an image plane of a pupil of the eye, and a compensator of high-order aberrations, 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, astigmatism compensator and compensator of high-order aberrations, projects an image of a test pattern onto the retina.
6. The instrument of claim 5 , wherein the refraction compensator comprises a movable prism and a dichroic mirror which are placed between two lenses, and wherein said dichroic mirror is operable as a beam-splitter to align the instrument.
7. The instrument of claim 5 , further comprising a built-in automatic calibration system which uses an additional virtual light source as a test element to measure current positions of the compensators.
8. The instrument of claim 5 , further comprising an alignment system which adjusts a proper distance between the eye and the instrument.