Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reexamination Certificate
2001-06-28
2003-09-09
Manuel, George (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
Reexamination Certificate
active
06616275
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and a device for correcting visual defects of the human eye.
In ophthalmology, it is known to shape the cornea by ablation of tissue in the case of amblyopia. In this context, the data on the aberration in the optical path of the eye is obtained by questioning the patient about his/her subjective impression of vision on the basis of corrections via standardized corrective lenses in front of the eye of the patient. Besides, methods exist for measuring the outer contour of the eye with the assistance of stripe- or ring-projection systems as are manufactured, for example, by the Orbtek, Tomey, or Technomed companies.
German Patent Application DE 197 05 119 A1 describes a method for improving a Shack-Hartmann sensor which can be used in the field of astronomy to measure wavefronts for surveying stars.
In German Patent 197 27 573 C1, a device and a method for shaping surfaces, in particular of lenses, by laser ablation of the surfaces is specified in a valuable contribution to the technological development.
It is felt to be a disadvantage of the related art that the correction of the lenses takes place only on the basis of suboptimum data on the causes of the visual defects such as irregularities of the cornea surface or aberration in the optical path. Consequently, only corrections according to the standard lens formulas of geometric optics are carried out.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a method and a device which permit complete correction of all refractive visual defects, including the aberrations of the optical path in the defective eye.
In particular, the objective is achieved by a device for correcting visual defects of an eye, including a coherent light source, a beam modification device for shaping and deflecting a beam of the coherent light source, provision being made for a wavefront analyzer device for analyzing a wavefront of the optical path in the eye. This device enables the data obtained from the analysis of the intraocular aberration to be taken into account in the correction of an existing optical system of an eye to be corrected. In this manner, the correction of the optical system of the eye is achievable with added precision.
The considered eye can be, in particular, a human eye but it is also conceivable to correct eyes of other living beings. Visual defects are, in particular, refractive visual defects such as myopia or hyperopia, irregularities of the cornea surface, or aberrations in the optical path.
Provided as coherent light source is preferably a laser, especially preferably a refractive laser, particularly preferably a spot scanning excimer laser. Conceivable is, moreover, a spot scanner using laser light in other ranges of the spectrum, such as a frequency-quintupled YAG laser, an IR laser of around 3 &mgr;m such as an Erbium:YAG laser emitting at 2.94 &mgr;m or a femtosecond laser (fs Laser).
The beam modification device is preferably composed of a device for shaping a beam and of a device for deflecting and aligning the beam. Preferably used as the device for shaping the beam are lens systems, diffractive structures, and refractive elements. Preferably used as the device for deflecting and aligning the beam are scanner arrangements, prisms, and mirrors.
Preferably usable as wavefront analyzer device is a Shack-Hartmann sensor, which is a sensor that is based on a method for analyzing wavefronts and is used, in particular in astronomy (see above). Using this wavefront analyzer device, it is possible to measure the whole wavefront emerging from the eye and, in this manner, to acquire data on the visual defects, including the intraocular aberration of the optical path also in the eye.
In a further exemplary embodiment of the present invention, provision is made for a device in which a topography analyzer unit for analyzing the surface of the eye is provided, as well. This analysis provides the data on the curvature and contour possessed by the eye surface, i.e., in particular by the cornea. In this manner, the complete data on the refractive visual defects of the eye is available to the system. Both the possibly not optimum surface contour of the eye, i.e., of the cornea, and the intraocular aberration can now be analyzed and are available to the system in the correction of the optical system of the eye. In this manner, it is possible to completely correct the visual defects of the eye and even to achieve a vision which exceeds that of the normal human eye. It is equally possible to correct aberrations only partly, thus producing a comprehensive correction only in combination with other vision aids. Preferably, it is also possible for aberrations to be generated purposely to make possible vision characteristics that are not or only rarely created by nature. These aberrations can then be selectively used for specific abilities (for example, spatial vision, accommodation, etc).
In a further exemplary embodiment of the present invention, provision is made for a device in which, moreover, a control unit for processing signals of the wavefront analyzer unit and/or for processing signals of the topography analyzer unit and/or for controlling the coherent light source and/or for controlling the beam modification device is provided. These control units permit evaluation of the data ascertained by the analyzer units. It is possible for the signals of the wavefront analyzer unit and the signals of the topography analyzer unit to be separately processed and evaluated in the control unit, or to process both data sets in one step. The control unit is preferably composed of several individual control units.
This data is preferably used for providing an ideal optical system. The parameters required for beam modification is determined from this data. These parameters can preferably be used in a further step for controlling the coherent light source, for example, to predetermine amplitude, pulse duration, and energy of the beam. Moreover, these parameters are also preferably used for controlling the beam modification device; here, to predetermine the target spot and the geometry of the beam in the target via the deflection of the beam.
Because of this, it is possible in a preferred exemplary embodiment to calculate, in particular, the shot positions for manufacturing the individual elements.
In a further preferred exemplary embodiment of the present invention, provision is made for a device in which the beam modification device is designed in such a manner that an intraocular lens and/or an eye lens and/or the cornea of the eye and/or a contact lens and/or an implantable contact lens (ICL) and/or a spectacle lens are processable via the beam. The beam, which is preferably controlled by the control unit, now enables an element or workpiece of the lens system to be processed in such a manner that the visual defects or aberration are completely corrected. Such an element is preferably an intraocular lens (IOL) which is prefabricated prior to a corresponding operation. This is particularly preferably an ICL (implantable contact lens) which is placed onto the lens. Based on the entire available data on the visual defects, including the aberration of the eye, this IOL or ICL can be shaped in such a manner that it corrects all existing visual defects. It is also conceivable for the correction to be carried out on the eye lens itself with the assistance of the beam which is preferably controlled by the control unit.
Moreover, it is conceivable to carry out a correction by processing the cornea. It is also preferred to manufacture contact lenses which, in a patient-specific manner, correct all individual defects going beyond the refractive eye defect, such as aberrations, unsymmetrical cylinders, and irregularities of the cornea. Besides, it is also possible to manufacture individual spectacle lenses. Besides excimer spot processing, methods of the optical industry, such as the single point diamond turning method, can also be used for this purpose. In t
Dick Manfred
Fiedler Joachim
Maeusezahl Holger
Molebny Vasyl
Schroeder Eckhard
Asclepion Meditec GmbH
Davidson Davidson & Kappel LLC
Manuel George
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