Method for determining objective refraction using wavefront sensing
View Patent ↗An apparatus for determining the objective refraction of a patient's eye includes a transparent window and a wavefront measurement device that determines aberrations in a return beam from the patient's eye after the beam passes through a corrective test lens in the apparatus. The wavefront measurement device outputs an instant display representative of the quality of vision afforded the patient through the test lens. The display can be a representation of a Snellen chart, convoluted with the optical characteristics of the patient's vision, an overall quality of vision scale or the optical contrast function, all based on the wavefront measurements of the patient's eye. The examiner may use the display information to conduct a refraction examination and other vision tests without the subjective response from the patient.
1. A method for determining a correction for a patient's eye, comprising:
directing light toward the patient's eye as the patient views a target through an optical test system;
successively measuring aberrations in a first plurality of wavefronts reflected from the patient's eye while the patient is viewing a target through an optical test system in a first configuration, the aberrations in the first plurality of wavefronts being indicative of the vision provided to the patient by the optical test system in the first configuration;
successively measuring aberrations in a second plurality of wavefronts reflected from the patient's eye while the patient is viewing the target through the optical test system in a second configuration, the aberrations in the second plurality of wavefronts being indicative of the vision provided to the patient by the optical test system in the second configuration;
calculating Quality of Vision Factor (QVF) values calculated from at least some of the measurements, the QVF defined as QVF=exp−(Σ n P n Z n 2 ) wherein Z n corresponds to coefficients for Zemike polynomials and P n corresponds to psychometric weight factors; and
determining whether the optical test system provides better vision correction for the patient's eye in the first configuration or the second configuration, the determination based at least in part the QVF values corresponding to the first and second plurality of measured wavefronts.
2. The method of claim 1 , wherein the optical system in the first configuration includes a first test lens disposed in an optical path between the patient's eye and the target and the optical system in the second configuration includes a second test lens disposed in the optical path.
3. The method of claim 2 , wherein the first test lens is interchangeable with the second test lens.
4. The method of claim 1 wherein the first test lens has a different optical power than the second test lens.
5. The method of claim 1 , further comprising generating at least one visual display representative of the effectiveness of the optical test system in the first configuration and the second configuration in correcting the patient's vision.
6. The method of claim 1 , further comprising calculating first and second standard deviation values from the calculated Quality of Vision Factors of the first and second plurality of wavefronts, respectively.
7. The method of claim 6 , wherein the determining step is based at least in part on the first and second deviation values.
8. A method for determining a correction for a patient's eye, comprising:
directing light toward the patient's eye as the patient views a target through an optical test system;
measuring a first wavefront reflected from the patient's eye while the patient is viewing a target through an optical test system in a first configuration, the optical test system configured to correct for aberrations of the patients eye so as to provide improved vision to the patient's eye;
measuring a second wavefront reflected from the patient's eye while the patient is viewing the target through the optical test system in a second configuration, the second wavefront being different from the first wavefront;
calculating Quality of Vision Factor (QVF) values calculated from the first and second wavefront measurements, the QVF defined as QVF=exp−(Σ n P n Z n 2 ) wherein Z n corresponds to coefficients for Zernike polynomials and P n corresponds to psychometric weight factors; and
determining whether the optical test system provides better vision correction for the patient's eye in the first configuration or the second configuration, the determination based at least in part the QVF values corresponding to the first and second measured wavefronts.
9. The method of claim 8 , wherein the optical test system in the first configuration includes a first test lens disposed in an optical path between the patient's eye and the target and the optical system in the second configuration includes a second test lens disposed in the optical path.
10. The method of claim 9 , wherein the first test lens is interchangeable with the second test lens.
11. The method of claim 10 , wherein the first test lens has a different optical power than the second test lens.
12. The method of claim 10 , wherein the optical test system further comprises a housing containing a wavefront measurement device and a substantially transparent window through which the patient can view the target.
13. The method of claim 12 , wherein the first and second test lenses are contained in the housing, the first and second test lenses being interchangeable along an optical path defined between the patient's eye and the target so that the first test lens is positioned along the optical path in the first configuration and the second test lens is positioned along the optical path in the second configuration.