DYNAMIC RANGE EXTENSION TECHNIQUES FOR A WAVEFRONT SENSOR INCLUDING USE IN OPHTHALMIC MEASUREMENT
An ophthalmic error measurement system includes a projecting optical system delivering light onto a retina of an eye, a pre-correction system which compensates a light beam to be injected into the eye for aberrations in the eye, the pre-correction system being positioned in between the projecting optical system and the eye, an imaging system which collects light scattered by the retina, and a detector receiving light returned by the retina from the imaging system. Use of the pre-correction system allows the end-to-end aberrations of the ocular system to be analyzed. The use of a pre-correction system also allows use of a minimized spot size on the retina, and all of its attendant advantages.
1 . A system for measuring errors in an eye, comprising:
a projecting optical system configured to focus light onto a retina of the eye;
an imaging system configured to receive light from the projecting optical system that is scattered by the retina;
a wavefront sensor configured to receive light returned by the retina from the imaging system; and
a target and a target optical system configured to project the target onto the eye so as to stimulate near vision accommodation of the eye.
2 . The system of claim 1 , wherein a relative distance between the target and the optical system is variable.
3 . The system of claim 1 , wherein the target is moveable relative to the target optical system.
4 . The system of claim 1 , further comprising a light source disposed behind the target, a brightness of the light source being electronically adjustable.
5 . The system of claim 1 , further comprising a pre-correction system configured to compensate a light beam to be injected into the eye for aberrations in the eye.
6 . The system of claim 3 , wherein the pre-correction system is positioned in between the projecting optical system and the eye.
7 . The system of claim 1 , wherein the system is configured to measure near vision visual acuity.
8 . The method of claim 1 , wherein the target optical system comprises a lens.
9 . The method of claim 8 , wherein the lens is a variable focal length lens.
10 . A method of measuring optical characteristics of an eye, comprising:
providing a measurement system including:
a projecting optical system;
an imaging system for receiving light scattered by the retina;
a wavefront sensor; and
a target system comprising a target and a target optical system;
projecting the target onto the eye;
stimulating near vision accommodation of the eye;
directing light from the light source onto a retina of the eye;
receiving in the imaging system light scattered by the retina;
receiving in the wavefront sensor the light received by the imaging system; and
measuring a near vision visual acuity of the eye.
11 . The method of claim 9 , wherein stimulating near vision accommodation includes varying an optical distance between the target and the eye.
12 . The method of claim 9 , wherein stimulating near vision accommodation includes moving the target relative to the target optical system.
13 . The method of claim 9 , wherein the target optical system comprises a lens.
14 . The method of claim 13 , wherein the lens is a variable focal length lens.
15 . A system for measuring errors in an eye, comprising:
a projecting optical system configured to focus light onto a retina of the eye;
an imaging system configured to receive light from the projecting optical system that is scattered by the retina;
a wavefront sensor configured to receive light returned by the retina from the imaging system;
a target and a target optical system configured to project an optical image of the target onto the eye;
wherein an optical distance between the target and the eye is variable so as to allow measurement of near vision visual acuity.
16 . The system of claim 15 , wherein the target is configured to stimulate near vision accommodation of the eye.
17 . The system of claim 15 , wherein the target is configured to be located so as to minimize accommodation of the eye.
18 . The system of claim 15 , wherein the target optical system comprises a lens.
19 . The system of claim 18 , wherein the lens is a variable focal length lens.