Patent Application
20080027538
a and 6b provide details of the blended polyspheric design transition of the anterior optic surface from the outside to the center of the lens.
According to the present invention the optic is of a foldable, flexible silicone, acrylic or hydrogel material and the haptic plates are of a foldable material that will withstand multiple foldings without damage, e.g., silicone. Preferably, the end of the plate haptics have T-shaped fixation devices and are hinged to the optic.
Turning now to the Figures, a preferred embodiment is illustrated in detail comprising an intraocular lens 1 formed as a flexible solid optic 2 preferably made of silicon, and flexible extending portions 4 of any suitable form which may be plate haptics or fingers which are capable of multiple flexations without damage and formed, for example, of silicone. The optic 2 and haptics 4 preferably are uniplanar, and one or more haptics 4 extend distally from opposite sides of the optic 2.
According to the present invention, the optic 2 has a central blended area 3. The lens 1 preferably comprises an accommodating intraocular lens currently available from eyeonics, inc., Aliso Viejo, Calif., such as shown in U.S. Pat. No. 6,387,126, typically with a 4.5 mm diameter optic, but with a polyspheric optic 3 and which has an added of less than 1 dioptor of power in the center of the lens 1 producing a single focal point. The area 3 is on the anterior side of the lens, and the posterior side can be any conventional form or can be toric if desired, or just the posterior surface behind the bulls eye could be toric. The added power area 3 is to aid in near vision by producing a single focal point with increased depth of focus. The optic diameter can range from approximately 3.5-8.0 mm but a typical one is 4.5-5.0 mm.
Non-accommodating intraocular lenses have been disclosed with a central area with a power of 2.0 diopters or more. Examples are in Nielson, U.S. Pat. No. 4,636,211, and Keats, U.S. Pat. No. 5,366,500. Such lenses result in the patient having two separate images, although the brain tends to ignore an unwanted image.
Importantly, with the present accommodating lens having a central area of less than 1.0 diopter the distant vision of the patient will slightly blur with no separate images, but also improve the near vision principally through an increased depth of field. Thus, there will not be two separate images, but a blurred primary image which when seen in one eye only, preferably with the other eye having a standard intraocular lens, is believed to essentially be not noticeable by the patient.
The haptics preferably are plate haptics having arcuate outer edges including loops 6. The loops 6 when unrestrained are somewhat less curved in configuration as shown in
The flexible haptics 4 and loops 6 can be connected to an acrylic optic 2 by means of an encircling elastic band (not shown) which fits into a groove in the acrylic optic 2 as shown and described in co-pending application Ser. No. 10/888,536 filed Jul. 8, 2004 and assigned to the assignee of the present application.
There can be a sharp edge 12 around the posterior surface 14 of the optic 2. The junction of the posterior surface 14 of the optic 2 to the edge of the lens 1 is a sharp edge or junction 12 designed to reduce the migration of cells across the posterior capsule of the lens post-operatively and thereby reduce the incidence of posterior capsular opacification and the necessity of YAG posterior capsulotomy. The anterior surface 16 of the optic 2 is closer to the groove 2 than is the posterior surface 14.
The present polyspheric concepts are applicable to several forms of lenses, such as lenses shown in Cumming U.S. Pat. Nos. 5,476,514, 6,051,024, 6,193,750, and 6,387,126.
a and 6b illustrate more detail of the blended polyspheric design of the anterior optic surface 16 and thus show the transition of the anterior optic surface from the outside surface of spherical radius SR1 to the center surface of the spherical radius of SR2 which comprises the central area 3 illustrated in the other Figures.
As is well known in the art, the intraocular lens 1 such as that in the drawings is implanted in the capsular bag of the eye after removal of the natural lens. The lens is inserted into the capsular bag by a generally circular opening torn in the anterior capsular bag of the human lens and through a small opening in the cornea or sclera. The outer ends of the haptics 4, or loops 6, are positioned in the cul-de-sac of the capsular bag. The outer ends of the haptics, or the loops, are in close proximity with the bag cul-de-sac, and in the case of any form of loops, such as 6, the loops are deflected from the configuration as shown for example in
There are two descriptions of central diopter and range that should be considered.
The lens design is sewed on the existing eyeonics Crystalens to the extent of the following:
Below are calculated dimensions of the optical section of the IOL for the minimum, average and maximum diopter lens. Diopter 1 is the dioptric power through the outer perimeter of the lens, and Diopter 2 is through the center section. Note that the radii are approximate as SR0 (posterior surface spherical radius) and SR1 (anterior surface spherical radius—outer area) aren't necessarily the same. The center thickness on the center area 3 is approximately 3 microns (0.003 mm) thicker over the 4 to 33 diopter range.
After the lens is manufactured, it is tumbled with a slurry of glass beads to remove any flashing, smooth the edges and integrate the radii, and it shrinks, resulting in an absence of discrete radii SR1-SR5, and thus ends up not a multiple power lens but a lens with a polyspheric front surface. The resulting blended design after completion does not cause separate images as does a multifocal lens, but actually provides a central curve which provides additional focusing power and actually results in an extended region of depth of field about the far point of the patient's vision. Thus, a desired depth of field increase about the focal point occurs, and the retinal image has been determined to be superior over a wider range than a standard accommodating intraocular lens. The through focus wavefront aberrations peak to valley and RMS graphs and Waveforms 1 and 2 below show quantitatively how the present ED-AIOL provides superior overall optical performance in the range of object vergence from infinity to 2 D. Thus, the lens functions simply by extending the range of accommodation about the far point by increasing the static depth of field. A patient's vision is improved by virtue of an increased depth of field, and this depth of field also will be present if the patient wears spectacles for near vision.
The Waveforms 1 are peak to valley wavefront aberrations for AIOL and ED-AIOL for object vergence distance from 0 D (object at infinity) to 2D (500 mm).
In the Waveforms 1 and 2 it can be seen that the AIOL provides lower wavefront aberration errors in terms of peak to valley and RMS values over the rage of object distance from infinity to about 4 M (0.25 D). For closer object distances (4 M to 500 mm), the ED-AIOL provides better optical performance. In the majority of the object vergence range, the ED-AIOL provides about 33% better P-V performance and about 50% better RMS performance compared to the AIOL. As can be seen from the lateral shift in the graphs, this corresponds to about a 0.3D improvement for the ED-AIOL. This again demonstrates the fact that the ED-AIOL should provide better overall performance over the depth of field range about the AIOL's focal point.
The end of the loops 6 containing the knobs 7 may be either integrally formed from the same material as the haptics 4 or the loops may be of a separate material such as polyimide, prolene, or PMMA as discussed below. The loops if formed of a separate material are molded into the terminal portions of the haptics 4 such that the flexible material of the loop 6 can extend by elasticity along the internal fixation member of the loop.
As noted above, the haptics 4 may have a groove or thin area 5 forming a hinge across their surface adjacent to the optic. This facilitates movement of the optic anteriorly and posteriorly relative to the outer ends of the haptics.
Accordingly, there has been shown and described a lens that ideally comprises a silicon optic and silicone haptic plates, loops that can be of a different material than the plate, and a fixation device at the end of each loop allowing for movement of the loops along the tunnel formed in the fusion of the anterior and posterior capsules of the human capsular bag, and wherein the anterior surface of the optic has a central area of increased power of less than 1 diopter as well as a method of implanting the lens in the non-dominant eye.
Various changes, modifications, variations, and other uses and applications of the subject invention will become apparent to those skilled in the art after considering this specification together with the accompanying drawings and claims. All such changes, modifications, variations, and other uses of the applications which do not depart from the spirit and scope of the invention are intended to be covered by the claims which follow.
