Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Methods of use
Reexamination Certificate
2002-05-31
2004-09-07
Casler, Brian L. (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Methods of use
C351S205000, C351S161000, C600S005000
Reexamination Certificate
active
06786602
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of vision correction, particularly to corrections achieved by means of spectacle lenses, contact lenses or intraocular lenses which include correction of high order aberrations.
BACKGROUND OF THE INVENTION
Currently performed optometric measurements for the determination of the specification of vision correction lenses generally measure aberrations of the type defocus and astigmatism, and to a lesser extent, also tilt. Common optometric devices for measuring defocus and astigmatism problems are the trial frame and the phoropter. Both devices rely on the subjective perception of the quality of sight perceived by the patient and therefore are referred to as subjective methods. Alternatively, an optical refractometer can be used for measuring defocus and astigmatism of the eye in an objective manner.
Aberrations such as tilt, defocus and astigmatism are considered low order aberrations. However, higher order aberrations, such as spherical aberration, coma and the even higher order aberrations, collectively known as irregular aberrations, are also present due to the imperfect optical properties of the human eye. The term “high order” or “higher order” aberrations, as used throughout this specification and as claimed, is meant to include all those aberrations besides the commonly corrected tilt, defocus and astigmatism aberrations. Furthermore, throughout this specification, and as claimed, the order by which aberrations are referred to are the orders of the wavefront aberrations, as expressed by their Zernike polynomial representation, rather than the order of ray aberrations. Under this convention, tilt, for instance is a first order aberration, defocus and astigmatism are second order aberrations, coma and coma-like aberrations are of third order, spherical and spherical-like aberrations are fourth order, and the above-mentioned irregular aberrations are those of fifth order and higher.
Once the diffraction limit of the eye's imaging capability has been exceeded, this occurring when the pupil size is typically larger than approximately 2 to 3 mm, the size of the minimum detail in the image projected onto the retina, and hence the ultimate visual acuity of the subject, becomes a function of how well the sum total of the aberrations present are corrected. If, in addition to the usually corrected power and astigmatism, higher order aberrations were also corrected, it would be possible to provide super-normal vision for the subject, with performance noticeably better than the commonly accepted optimum vision acuity, known as 20/20 vision. Since, however, correction of the low order aberrations generally improves vision to an acceptable level, little effort has historically been made to attempt to correct for the higher order aberrations present in the eye. Furthermore, even though low order aberration correction may provide acceptable visual acuity during the daytime or in well-lit rooms, under which conditions the pupil aperture is small, the level of low order correction may prove to be unacceptable at lower light levels, when the pupil aperture is larger and the level of aberrations increases.
In order to be able to correct higher order aberrations, the extent of these aberrations must be measured, and corrective measures then applied, such as the prescription of correction lenses or the performance of eye surgery. Different methods for measuring high order aberrations are described, for instance in U.S. Pat. No. 6,155,684, for “Method and Apparatus for Precompensating the Refractive Properties of the Human Eye with Adaptive Optical Feedback Control” to Bille et al.
A subjective method for measuring high order aberrations is described In Israel patent application No. 137,635 for “Apparatus for Interactive Optometry”, filed by the applicants of the present application.
Recent developments in the field of high order aberration correction for the human eye have, to date, only involved either corrective action such as laser surgery, or the use of contact lenses or intraocular lenses. Effective correction of higher order aberrations using spectacles has not hitherto been considered possible, since effective correction of such higher order aberrations is sensitive to the direction of passage of the light through the lens. In the case of spectacles, the optical axis of the spectacle lens and the optical axis of the eye may deviate from each other, both because of the natural rolling action of the eyeballs and also because of the limited accuracy with which the spectacles may be fixed relative to the wearer's eyes.
In the published PCT application in Patent Document WO 00/75716 for “Super Vision” to E. I. Gordon, there is described a method of correcting for spherical aberrations in human vision by means of an aspherical lens design, but the method does not utilize full wavefront measurement. In this document, it is stated specifically that the suggested solution is inadequate for use with spectacle lenses, since “because of deviations between the corneal vision axis and the axis of the lens, eye glass (spectacle) type corrections are not however feasible unless some means are used to fix the cornea relative to the spectacle lens.”
In U.S. Pat. No. 5,220,359 to J. H. Roffman for “Lens Design Method and Resulting Aspheric Lens”, there is described a solution for aberration correction in contact, intraocular, natural or spectacle lenses. However, the suggested solution is for aspherical lenses only, which are rotationally symmetric. Furthermore, the method is a subjective method of substituting aspheric lenses until the optimum subjective correction is achieved, and does not involve a complete wavefront measurement.
Contact lenses and intraocular lenses, however, being more or less fixed relative to the eyes, are not considered to suffer from the above-mentioned disadvantage of spectacle lenses. In U.S. Pat. Nos. 5,777,719, 5,949,521 and 6,095,651, all for “Method and Apparatus for Improving Vision and the Resolution of Retinal Images” to D. R. Williams et al. (each a continuation of the previous), there are described methods of providing correction data of higher order aberrations for use in the manufacture of contact lenses and intraocular lenses, as illustrated in FIG. 1 of each of these patents. Very sparse enabling details are given, however, of how to apply the measurements obtained in the design of contact or intraocular lenses.
The majority of sight correction is still, however, currently achieved by the use of spectacles, this probably being the least expensive, most risk-free and most convenient method of sight correction. There therefore exists an important need for the provision also of spectacle lenses corrected for higher order aberrations.
The disclosures of each of the publications mentioned in this section, and in other sections of this specification, are hereby incorporated by reference, each in its entirety.
SUMMARY OF THE INVENTION
The present invention seeks to provide a new spectacle lens for the correction of human vision, including the correction of high order aberrations, and a method for constructing such a lens. The present invention thus enables the provision of super normal vision using spectacles. Different lenses are described for use at a partial or a fuller field of view (FoV). The method applies corrective measures based on data obtained from high order wave front measurements. Although the method of the present invention is described in this specification using its implementation in the prescription of spectacle lenses as a preferred embodiment to illustrate the method, it is to be understood that it may also be implemented with any other vision corrective measures such as contact lenses, intraocular lenses or even in refractive eye surgery.
As opposed to prior art methods of correcting high order aberrations in vision, using real-time wavefront measurements and corrective adaptive optics, the present invention achieves the correction by means of a suitably constructed fixed lens
Casler Brian L.
Sanders John R
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