Corrective intraocular lens

An intraocular lens includes a optical body including a posterior concave rface with a first radius of curvature, a periphery and a central, axially aligned opening that enhances liquid circulation in the eye, with the ratio of the height of the optical body to the overall height of the lens being between about 0.25 to about 0.5; a positioning element connected to the optical body periphery and including a periphery and a posterior concave surface with a second radius of curvature greater than the first radius of curvature, a ratio of the first to second radii of curvature being between about 0.31 to about 0.42; and end elements connected with opposite ends of the positioning element, each end element including a proximal end connected with the positioning element periphery, a distal end, a posterior concave surface forming a smooth continuation of the positioning element posterior concave surface and having a curvature identical therewith, and an anterior surface on an opposite side of the end element, the end element anterior surface having a substantially linear slope such that the end element decreases in thickness from the proximal end to the distal end, and the intraocular lens having an outer dimension defined by the distal ends of the end elements which prevents anchoring of the intraocular lens in an eye and thereby permits floating of the intraocular lens in the eye.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to medicine, and more specifically 
to ophthalmology, and has particular reference to a corrective intraocular 
lens which finds successful application for treatment of myopia, 
hyperopia, astigmatism, and other eye diseases. 
2. Description of the Prior Art 
Correction of such eyesight deficiencies as myopia, hyperopia, and the like 
has conventionally involved the use of glasses or contact lenses. However, 
correction with the use of such devices is temporary, since such devices 
must be placed and removed periodically, for example, while skiing, 
swimming and the like. 
Permanent correction of eyesight is performed with the aid of keratotomy. 
One of these techniques includes removal of the corneal layer and its 
reshaping, while another technique includes the making of a multiplicity 
of radial cuts into the corneal layer to adjust the curvature thereof, 
followed by healing. The aforesaid kerato-refractive surgical techniques 
are of an irreversible nature and suffer from inadequate accuracy of 
prognostication of the postoperative refractive effect. 
Intraocular lenses or lenticuli have been used to solve these problems, but 
they are intended largely for correction of postcouching aphakia. 
There has been provided a corrective lens for use in conjunction with the 
intact natural lens, such as that described in U.S. Pat. No. 4,585,456 
issued on Apr. 29, 1986 to Blackmore. This corrective lens employs an 
optical body formed of a material biocompatible with the eye and having a 
concave posterior surface with a curvature that fits the curvature of the 
external surface of the natural lens. The aforesaid optical body includes 
a means for positioning it so that it is adjacent to the natural lens. To 
retain the corrective lens in this position, provision is made for 
supporting elements shaped as, for example, open loops associated with the 
positioning means as is known in the art with respect to intraocular 
lenses. When inserting such a corrective lens within the patient's eye, 
the supporting elements are placed in the ciliary sulcus. However, such an 
attachment is subject to various disadvantages inherent in fastening of an 
intraocular lens in the ciliary sulcus and, in particular, the rather 
frequent danger-of inflammation of the ocular tissues. Moreover, as it has 
been confirmed by practical experience, such an attachment might be 
inadequately reliable and results in dislocation or displacement of the 
corrective lens. 
There is known in the prior art an intraocular lens which includes an 
optical body having a posterior concave surface, an anterior surface and a 
periphery. The lens further includes a positioning element in surrounding 
relation to the optical body and connected to the periphery thereof, the 
positioning element including a periphery and a posterior concave surface 
that forms a smooth continuation of the optical body posterior concave 
surface and which has a curvature identical to the curvature of the 
optical body posterior concave surface. Finally, the lens includes a 
supporting element including a proximal portion connected with the 
positioning element periphery, a distal portion adapted to contact a zonal 
ligament, a posterior concave surface on one side of the supporting 
element between the proximal portion thereof and the distal portion, the 
supporting element posterior concave surface forming a smooth continuation 
of the positioning element posterior concave surface and having a 
curvature identical to the curvature of the positioning element posterior 
concave surface. The supporting element further includes an anterior 
surface on an opposite side of the supporting element between the proximal 
portion and the distal portion thereof, the supporting element anterior 
surface having a concavity which has an opposite direction of curvature 
from the supporting element posterior concave surface, such that the 
supporting element non-linearly decreases in thickness between the 
supporting element anterior surface and the supporting element posterior 
concave surface, from the proximal portion to the distal portion thereof. 
However, with such corrective lens for use in conjunction with the intact 
natural lens, the lens is secured to the zonal ligaments. As a result, the 
lens is at a fixed position in the eye. However, in some instances, the 
pupil of the eye may be off-center, for example, offset upwardly and 
toward the nose. Although this lens functions well when the pupil of the 
person is centered in the eye, this lens does not function as well when 
the pupil is off-center. This is because the lens is fixed to the zonal 
ligaments at a predetermined position in the eye. In such case, the 
corrective lens is fixed and can only contract and expand. 
Further, because the lens is fixed in the eye, it is limited to a 
relatively small range of diopters, and has, for example, an upper limit 
of use with a -12 diopter. 
Still further, with the aforementioned corrective lens, because there is a 
thickened portion at the intersection of the positioning element with the 
optical body, when the lens is inserted in the eye, a force is applied to 
the iris. As a result, the iris is biased into a substantially 
frusto-conical configuration. This is disadvantageous, and rather, it is 
desirable that the iris remain in its original substantially planar 
configuration. 
Also, with corrective lenses that are fixed in the eye, it is necessary to 
remove portions of the iris in order to provide circulation of liquid in 
the eye, which is essential to normal operation of the eye. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a 
corrective lens for use with the natural crystalline lens of the eye. 
It is another object of the present invention to provide such a corrective 
lens which floats in the eye. 
It is still another object of the present invention to provide such a 
corrective lens which thereby follows the pupil of the eye at all times. 
It is yet another object of the present invention to provide such a 
corrective lens in which the iris is maintained in a substantially planar 
configuration. 
It is a further object of the present invention to provide such a 
corrective lens which enables circulation of liquid in the eye without 
removing any portion of the iris. 
It is a still further object of the present invention to provide such a 
corrective lens which can be used with a wide range of diopters from about 
0 to about -25, and with a preferred practical range of about -10 to about 
-25. 
It is a yet further object of the present invention to provide such a 
corrective lens that is relatively easy to manufacture and easy to insert. 
In accordance with an aspect of the present invention, an intraocular lens 
for use with a natural crystalline lens of an eye, the eye having an iris, 
includes optical body means for centering the intraocular lens in the iris 
of the eye, the optical body means having a periphery; and positioning 
means for supporting the intraocular lens in a floating manner on the 
natural crystalline lens of the eye, the positioning means being connected 
with the periphery of the optical body means. 
Specifically, the optical body means has a posterior concave surface with a 
radius of curvature, and dimensions that permit the optical body to fit 
within the iris of the eye; and the positioning means includes a posterior 
concave surface that conforms to the natural crystalline lens of the eye. 
At least one end element is connected at opposite ends of the positioning 
element, each end element including a posterior concave surface forming a 
smooth continuation of the posterior concave surface of the positioning 
means and decreasing in thickness in a direction away from the positioning 
means; and the intraocular lens having an outer dimension which prevents 
anchoring of the intraocular lens in an eye such that the positioning 
means and the at least one end element float on the natural crystalline 
lens and the optical means is centered in the iris. 
The optical means further includes opening means for providing circulation 
of liquid in the eye, the opening means being positioned substantially 
centrally of the optical means. 
In accordance with another aspect of the present invention, an intraocular 
lens for use with a natural crystalline lens of an eye, includes an 
optical body through which vision occurs, the optical body having a 
periphery and opening means for providing circulation of liquid in the 
eye, the opening means being positioned substantially centrally of the 
optical body; and positioning means for supporting the intraocular lens on 
the natural crystalline lens of the eye, the positioning means being 
connected with the periphery of the optical body. 
Preferably, the opening has a diameter in the range of about 0.4 mm to 
about 0.5 mm. 
In accordance with still another aspect of the present invention, an 
intraocular lens for use with a natural crystalline lens of an eye, the 
eye having an iris, includes an optical body including a posterior concave 
surface with a first radius of curvature, and a periphery; a positioning 
element in surrounding relation to the optical body and connected to the 
periphery of the optical body, the positioning element including a 
periphery and a posterior concave surface with a second radius of 
curvature greater than the first radius of curvature; and end elements 
connected with opposite ends of the positioning element, each end element 
including a proximal end connected with the periphery of the positioning 
element, a distal end, a posterior concave surface which forms a smooth 
continuation of, and has a curvature identical to, the posterior concave 
surface of the positioning element, and an anterior surface having a slope 
such that the end element decreases in thickness from the proximal end to 
the distal end; and the intraocular lens having an outer dimension defined 
by the distal ends of the end elements which prevents anchoring of the 
intraocular lens in an eye such that the positioning element and the at 
least one end element float on the natural crystalline lens and the 
optical body is centered in the iris. 
Each of the optical body and the positioning element has a substantially 
constant thickness. 
Further, the optical body has an opening extending therethrough. The 
opening extends along an axial direction of the optical body and is 
substantially centrally positioned on the optical body. 
In addition, the anterior surface of each end element has a substantially 
linear slope. 
In accordance with yet another aspect of the present invention, an 
intraocular lens for use with a natural crystalline lens of an eye, the 
eye having an iris, and the intraocular lens having an overall height, 
includes a part spherical optical body including a posterior concave 
surface with a first radius of curvature, and a periphery, the optical 
body having a height, with a ratio of the height of the optical body to 
the overall height being in the range of about 0.25 to about 0.5; a part 
spherical positioning element in surrounding relation to the optical body 
and connected to the periphery of the optical body, the positioning 
element including a periphery, and a posterior concave surface with a 
second radius of curvature greater than the first radius of curvature, a 
ratio of the first radius of curvature to the second radius of curvature 
being within a range of about 0.31 to about 0.42; and end elements 
connected with opposite ends of the positioning element, each end element 
including a proximal end connected with the periphery of the positioning 
element, a distal end, a posterior concave surface forming a smooth 
continuation of, and having a curvature identical to, the posterior 
concave surface of the positioning element, and an anterior surface having 
a slope such that the end element decreases in thickness from the proximal 
end to the distal end; and the intraocular lens having an outer dimension 
defined by the distal ends of the end elements which prevents anchoring of 
the intraocular lens in an eye such that the positioning element and the 
end elements float on the natural crystalline lens and the optical body is 
centered in the iris. 
Preferably, the optical body has an outer diameter in the range of about 
4.0 mm to about 5.5 mm, and the opening is circular and has a diameter in 
the range of about 0.4 mm to about 0.5 mm. Further, the positioning 
element has an outer dimension in the range of about 9.4 mm to about 10.2 
mm. In addition, each end element has a thickness of about 0.1 mm at the 
proximal end thereof, a thickness of about 0.01 mm at the distal end 
thereof, and a length of about 0.3 mm. 
In accordance with a further aspect of the present invention, an 
intraocular lens for use with a natural crystalline lens of an eye, the 
eye having an iris, and the intraocular lens having an overall height, 
includes a part spherical optical body having an outer diameter in the 
range of about 4.0 mm to about 5.5 mm and having a height, with a ratio of 
the height of the optical body to the overall height being in the range of 
about 0.25 to about 0.5, and the optical body including a posterior 
concave surface with a first radius of curvature, a periphery, and a 
circular opening extending therethrough along an axial direction of the 
optical body and substantially centrally positioned on the optical body, 
the opening having a diameter in the range of about 0.4 mm to about 0.5 
mm; a part spherical positioning element in surrounding relation to the 
optical body and connected to the periphery of the optical body, the 
positioning element including a periphery having an outer dimension in the 
range of about 9.4 mm to about 10.2 mm, and a posterior concave surface 
with a second radius of curvature greater than the first radius of 
curvature, a ratio of the first radius of curvature to the second radius 
of curvature being within a range of about 0.31 to about 0.42; and end 
elements connected with opposite ends of the positioning element, each end 
element including a proximal end connected with the periphery of the 
positioning element, a distal end, a posterior concave surface forming a 
smooth continuation of, and having a curvature identical to, the posterior 
concave surface of the positioning element, and an anterior surface having 
a substantially linear slope such that the end element decreases in 
thickness from the proximal end to the distal end; and the intraocular 
lens having an outer dimension defined by the distal ends of the end 
elements which prevents anchoring of the intraocular lens in an eye such 
that the positioning element and the end elements float on the natural 
crystalline lens and the optical body is centered in an iris of an eye.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIGS. 1 and 2, there is shown a corrective lens 10 
according to the present invention which is intended for correction of a 
phakic eye. Such a lens can be produced by molding from a material such as 
polymethyl-methacrylate, silicone rubber, polyhydroxyethyl-methacrylate, 
the copolymer of silicone and methylmethacrylate, polyvinylpyrrolidone, 
and other materials which are biocompatible with the ocular tissue and 
aqueous humor and preferably hydrophilic and/or permeable to oxygen. 
Corrective lens 10 includes a part spherical optical body 12 having a 
concave posterior surface 12a and an anterior surface 12b of the same 
curvature. Therefore, the thickness of optical body 12 is substantially 
uniform or constant throughout. Posterior surface 12a is located on the 
side corresponding to the outer surface of the natural crystalline lens 14 
(FIG. 4) and has a radius R1 of curvature which is preferably within the 
range of about 3.0 to about 3.5 mm. Further, optical body 12 preferably 
has an outer diameter D1 in the range of about 4.0 to about 5.5 mm. 
Optical body 12 is encompassed and integrally formed along its entire 
circumference by a part spherical positioning element 16, having a 
posterior concave surface 16a with a radius R2 of curvature equal to the 
radius of curvature of the outer surface of natural crystalline lens 14, 
as shown in FIG. 4. The radius R2 of curvature preferably ranges between 
about 9.0 and 10.0 mm. Positioning element 16 also has an anterior surface 
16b of the same curvature as posterior surface 16a, and therefore, the 
thickness of positioning element 16 is substantially uniform or constant 
throughout. Positioning element 16 serves to set optical body 12 in the 
eye on the outer surface of the intact natural crystalline lens 14 in the 
course of orienting optical body 12 with respect to the natural 
crystalline lens. Positioning element 16 preferably has an outer dimension 
D2 which ranges from about 9.4 mm to about 10.2 mm. 
End elements 18 are formed at opposite ends of positioning element 16 and 
are thinned as compared with positioning element 16, as can be seen from 
the enlarged cross-sectional view of FIG. 3. Preferably, the inner 
thickness T of each end element 18 is equal to about 0.1 mm (which is the 
same thickness as positioning element 16 and optical body 12), while the 
outer thickness t of each end element 18 at its peripheral surface is 
about 0.01 mm. However, the edge of the end portion must not be 
excessively sharp for fear of injuring the eye tissue with the edge. 
Taking account of the fact mentioned above, it is expedient to make the 
thinning along a substantially linear generant on the side of the anterior 
surface 18b of each end element 18. The posterior surface 18a of each end 
element 18 has the same radius R2 of curvature as the posterior surface 
16a of positioning element 16. The distance D3 between the diametrically 
opposite ends of end elements 18 preferably ranges from about 10.0 mm to 
about 10.8 mm. In other words, each end element 18 preferably has a length 
L of about 0.3 mm. It will therefore be appreciated that this range is 
less than the diametric distance between the Zinn's zonules or Zinn 
ligaments 20 (FIG. 4), so that lens 10 is free to float in the eye. 
It is important that certain parameters be satisfied in order for the lens 
10 to correctly fit within the eye. Thus, it is important that the ratio 
of the height h of optical body 12 over the overall height H of lens 10 be 
in the range of about 0.25 to about 0.5, that is, h/H=0.25.about.0.5. 
Further, it is important that the ratio of radius R1 to radius R2 be in 
the range of about 0.31 to about 0.42, that is, R1/R2=0.31.about.0.42. 
Accordingly, with the present invention described above, a corrective lens 
10 for use with the natural crystalline lens 14 of the eye is provided so 
as to float in the eye. As a result, corrective lens 10 thereby follows 
the pupil of the eye at all times, regardless of the same being offset or 
eccentric. In other words, intraocular lens 10 has an outer dimension 
defined by the distal ends of end elements 18 which prevents anchoring of 
intraocular lens 10 in an eye such that positioning element 16 and end 
elements 18 float on the natural crystalline lens 14, and such that 
optical body 12 is centered in iris 22 of an eye. Further, as shown in 
FIG. 4, the iris 22 is maintained in a substantially planar configuration, 
as with the natural eye. 
In the situation where the iris 22 contracts, for example, in the presence 
of a strong light, optical body 12 will still remain centered within iris 
22. However, in such case, iris 22 will ride up along the surface of 
optical body 22 so that the iris will be inclined outwardly. 
In accordance with a further aspect of the invention, optical body 12 is 
provided with an central, axially aligned opening 24 therein. Opening 24 
preferably has a diameter D4 in the range of about 0.4 mm to about 0.5 mm. 
By providing opening 24, there is always proper circulation of liquid in 
the eye, and there is no need to remove any portion of iris 22 to provide 
such circulation. It is noted that, because of the focusing of light from 
other portions of optical body 12, the wearer of the lens 10 will not 
notice any defect in the produced image from opening 24. At most, there 
will be a slight darkening of the image, which also will not be noticed by 
the wearer of lens 10. 
The above-described corrective lens 10 can be used in a wide range of 
diopters from about 0 to about -25. From a practical standpoint, the range 
of use of corrective lens 10 will be with diopter values ranging from 
about -10 to about -25. 
The proposed corrective lens is positioned as follows. 
Under local anesthesia, an incision into the cornea or limbus is made to 
establish an access to an anterior eye chamber 26 (FIG. 4). Then, 
corrective lens 10 is introduced, using forceps, through the preliminary 
dilated pupil, into posterior eye chamber 28 at 6 o'clock, and then at 12 
o'clock. Next, corrective lens 10 is adjusted for position by moving it 
with its posterior concave surface 16a over the outer surface of intact 
natural crystalline lens 14. As a result of this positioning, optical body 
12 is arranged on the eye optic axis within the opening in iris 22. On 
completion of surgery, the operative incision is stitched up. 
While a preferred embodiment of the invention has been disclosed herein, it 
will be understood that various modifications and versions may occur to 
those skilled in the art without departing from the spirit and scope of 
the present invention as defined by the claims that follow.