Surgery – Instruments – Light application
Reexamination Certificate
1995-07-25
2001-11-06
Shay, David M. (Department: 3739)
Surgery
Instruments
Light application
C606S010000, C606S013000, C128S898000
Reexamination Certificate
active
06312424
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to vision correction and more particularly to vision correction by shaping of the cornea.
BACKGROUND OF THE INVENTION
As is well known, vision correction is often obtained through the use of ophthalmic lenses, such as eye glasses and/or contact lenses. It is also known to employ corneal inlays, corneal onlays and intraocular lenses.
Another technique for vision correction is to modify the cornea, and this can be done, for example, through a radial keratotomy procedure. It is also known to shape the cornea utilizing a laser and to correct for nearsightedness, farsightedness or astigmatism.
It is not uncommon, however, for a patient to require correction for both near and far distances, and some patients also need correction for intermediate distances. It is also desirable at least in some instances to provide a patient with progressive vision correction powers. Although this can be accomplished thorough the use of ophthalmic lenses, so far as I am aware, multifocal correction and progressive correction through cornea shaping are not taught in the prior art.
SUMMARY OF THE INVENTION
This invention provides a method of vision correction which achieves multifocal and/or progressive vision correction through shaping of the cornea thereby enabling these corrections to be obtained without the need for an ophthalmic lens. The shaping of the cornea alters the configuration of the anterior surface of the cornea thereby changing its refraction. This cornea shaping technique can be utilized for patients having their natural lens or an intraocular lens.
The method of vision correction may include shaping first and second regions of the anterior surface of a cornea to provide the first region with a surface configuration which provides a first vision correction power and to provide the second region with a surface configuration which provides a second vision correction power which is different from the first vision correction power to enhance vision at first and second different distances, respectively. For example, the distances may be near and far distances to thereby provide a bifocal effect. Of course, the cornea shaping may be carried out to achieve trifocal correction or any other desired number of steps of vision correction.
An important feature of the invention is that the cornea may be shaped to provide progressive vision correction powers. For example, the step of shaping may include shaping a third region of the cornea between the first and second regions to provide a surface configuration which provides the progressive vision correction powers with the progressive vision correction powers including vision correction powers which are between the first and second vision correction powers.
The specific configuration of the power curve across the cornea can be tailored to suit the needs of the patient and particular design considerations. However, the preferred method includes shaping a fourth region of the cornea to provide a surface configuration which provides progressive vision correction powers which include progressive vision correction powers which are between the first and second vision correction powers. The second region is between the third region and the fourth region.
Likewise, the particular configuration of the regions which are shaped can differ widely. Preferably, however, each of the shaped regions is annular with the annular regions being in appropriate circumscribing relationship.
It also may be desirable to shape a central region of the cornea. In one preferred arrangement, the central region of the cornea is shaped to provide a vision correction power intermediate the first and second vision correction powers. Preferably the vision correction power of the central region includes an intermediate vision correction power.
It is conceivable that some time after the regions of the cornea are appropriately shaped to provide the desired vision correction that these regions will lose their shape and desired vision correction due to, for example, growth of the cornea. If this should occur, the method of this invention, and in particular the shaping steps of the method may be carried out again on the cornea of the patient to restore the desired configuration to thereby reestablish the desired vision correction. In addition, the same patient may require or desire further shaping of the cornea at some later date if, for example, the natural lens of the patient loses more accommodation.
Although the shaping of the cornea may be carried out in any suitable way, it is currently preferred to shape the cornea utilizing laser energy. Although this can be accomplished by scanning a laser beam across the cornea, it is preferred to utilize a mask which appropriately modulates the laser energy so the laser energy can shape the regions of the cornea to provide the desired vision correction powers.
According to one technique, laser energy is directed to a mask to provide a modulated laser beam having different energy levels at different locations across the modulated laser beam. The laser beam is then directed to the cornea to ablate the cornea to different degrees to provide the cornea with progressive vision correction powers and/or bifocal or trifocal powers. The different energy levels of the modulated laser beam enable the laser beam to accomplish differential ablation of the cornea to achieve the desired shape of the cornea. In order to provide the different energy levels, the mask may have variable or differential transmissivity or reflectivity to the laser energy provided by the laser. The mask may provide the modulated laser beam with appropriate annular zones which are capable of ablating annular regions of the cornea to achieve the desired cornea shaping effect.
The invention together with additional features and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying illustrative drawings.
REFERENCES:
patent: 4665913 (1987-05-01), L'Esperance, Jr.
patent: 4729372 (1988-03-01), L'Esperance, Jr.
patent: 4798204 (1989-01-01), L'Esperance, Jr.
patent: 4842782 (1989-06-01), Portney et al.
patent: 4856513 (1989-08-01), Muller
patent: 4941093 (1990-07-01), Marshal et al.
patent: 4994058 (1991-02-01), Raven et al.
patent: 5225858 (1993-07-01), Portney
patent: 5270744 (1993-12-01), Portney
patent: 5533997 (1996-07-01), Ruiz
patent: 0372127 (1990-06-01), None
patent: 9325166 (1993-12-01), None
Excimer Laser Surgery of the Cornea by Stephen L. Troekel, M.D. Sep. 1983 American Journal of Ophthalmology 96:710-715.
Allergan
Shay David M.
Stout, Uxa Buyan & Mullins, LLP
Uxa Frank J.
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