Intraocular Lens With Glare-Inhibiting Closure, the Method of Inhibiting Glare, and the Closure for Same

This invention relates to intraocular lenses for the human eye, and, more particularly, to intraocular lenses of the type which have a positioning hole and which can be positioned in the anterior chamber, the posterior chamber, or partially in the anterior chamber and partially in the posterior chamber of the eye.

Conventionally, in the seating of intraocular lenses, such as, for example, the lenses described and claimed in my U.S. Pat. No. 4,253,200 issued Mar. 3, 1981, such a lens is inserted into the eye through a corneo-scleral incision that may be also used to remove a natural lens. For seating such an intraocular lens in the eye it is typically provided with one or more openings, usually in the form of one or more bores, or positioning holes, allowing the surgeon to manipulate the lens into seating position by use of a surgical instrument whose tip is inserted into such positioning hole. The positioning holes, however, are conventionally located in the optic proper and have the disadvantage that, even though they are typically located near the periphery of the optic, they frequently result in the patient perceiving a glare-effect, particularly if the lens becomes decentered after implantation and such positioning hole is displaced toward the optical axis. It must be remembered, in this connection, that the peripheral wall of such positioning hole forms a boundary between the material of the optic, usually polymethylmethacrylate (PMMA) and the fluid within the eye which fills the hole when the lens is seated in the eye. A boundary between materials having such vastly different indices of refraction as the PMMA of the lens body, on the one hand, and the agueous humor in the eye, on the other hand, can cause a glare effect perceived by the user.

It is an object of the present invention, therefore, to provide a new and improved intraocular lens which avoids one or more of the disadvantages of prior such lenses.

It is another object of the invention to provide a new and improved intraocular lens which is constructed so as to minimize the glare which would otherwise result during use.

It is still another object of the invention to provide a new and improved intraocular lens, which inhibits undesirable glare from positioning holes even when the lens is decentered.

It is yet another object of the invention to provide a glare-inhibiting closure for the positioning hole of intraocular lenses.

It is a further object of this invention to provide a method for inhibiting the glare effect caused by the positioning hole of an intraocular lens.

It is a concomitant object of the invention to provide a new and improved intraocular lens which has an instrument-receiving positioning hole and glare inhibiting means associated with that hole.

Glare effect is produced whenever there is located, in the path of the light rays which pass through the pupil to the retina, an edge or similar boundary between regions which are both substantially transparent as distinguished from one of them being substantially opaque or at least not substantially transparent. For example, glare effect is likely to result if a lens is decentered and light rays passing through the pupil pass through the positioning hole, specifically, through the optically transparent fluid of the eye, exhibiting a given index of refraction, which fills such hole, while adjacent rays pass through the optically transparent material of the optic itself, exhibiting a different index of refraction. Such glare may be eliminated or at least minimized, however, by masking the positioning hole after the lens has been seated in the eye, providing an effect similar to that provided by the human iris. It is well known that due to its opacity the iris "masks" without any resulting glare-effect.

In accordance with the invention, an intraocular lens comprises a lens body, or optic, for focusing light rays on the retina of an eye. The lens body has an instrument-receiving positioning hole, or bore and masking means insertable into and removable from such bore, after the lens is seated in the eye, for masking the edge regions of the bore to eliminate or inhibit the glare effect otherwise resulting from light rays passing thru such bore. The masking means prevents, light rays which are directed toward the edge regions of such bore from passing therethrough in a recognizable, i.e. undiffused, form toward the retina, after the lens has been seated in an eye.

According to a preferred embodiment of the invention there is provided a lens body comprising anterior and posterior optically polished surfaces shaped to focus, on the retina, light rays entering the eye. A positioning hole in the form of a bore is provided in the lens body extending from one toward the other of said surfaces. The bore is adapted to receive therein the tip of a surgical instrument used to manipulate the lens body within the eye. Plug means, incorporating masking means are provided and are adapted to cooperate with the bore for preventing light rays in the region of the periphery of the bore from continuing toward the retina in a recognizable, i.e. undiffused form, whereby the glare effect otherwise experienced as a result of light rays passing through such bore, adjacent to light rays passing through the portion of the lens body immediately surrounding such bore, is substantially reduced. The plug means are adapted to be removeable received in the bore and when so received therein, provide an opaque or at least semi-opaque barrier to light rays attempting to pass thru such bore.

According to another preferred embodiment, there is provided a plug member adapted to be removably received in the positioning hole in a lens body. The plug member is preferably of a size and shape comparable to the size and shape of the positioning hole and is adapted to be securely retained therein. The plug is preferably opaque, or at least semi-opaque, so that when inserted in the positioning hole, the plug prevents light rays otherwise passing through such positioning hole to continue toward the retina, at least not in a recognizable, or undiffused, condition.

The invention further includes the method of seating within an eye an intraocular lens having a positioning hole, comprising: positioning the lens within the eye with an instrument whose tip is inserted in the positioning hole of the lens, removing the tip of the instrument from the positioning hole after the lens has been seated, inserting into the positioning hole, a plug providing an at least semi-opaque barrier to light rays attempting to pass through the positioning hole and removably retaining said plug in the positioning hole.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description, taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

Referring now to the drawings:

FIG. 1 is a front elevational view of the intraocular lens embodying a preferred form of the present invention;

FIG. 2 is a partial, enlarged, transverse sectional view along line 2--2 of FIG. 1;

FIG. 3 is an enlarged fragmentary view of the portion of the lens body containing the plug received in the positioning hole as shown in FIGS. 1 and 2;

FIG. 4 is a side elevational view of the intraocular lens represented in FIG. 1, showing the latter seated in a eye;

FIG. 5 is an enlarged fragmentary view of a portion of a lens body containing the positioning hole with a plug received therein according to another embodiment of the invention;

FIG. 6 is a fragmentary transverse sectional view along line 6--6 of FIG. 5;

FIG. 7 is a front elevational view of another preferred embodiment of lens according to the present invention;

FIG. 8 is a partial, enlarged, transverse, sectional view along Line 8--8 of FIG. 7;

FIG. 9a is a side elevational, enlarged, view of a plug according to one embodiment of the present invention;

FIG. 9b is a side elevational, enlarged, view of another embodiment of a plug according to the present invention; and

FIG. 9c is a side elevational, enlarged view of still a further embodiment of a plug according to the present invention;

Referring now to the drawings, reference numeral 1, in FIG. 1, generally indicates an intraocular artificial lens according to a preferred embodiment of the present invention. The lens 1 can be formed of any suitable material compatible with the environment of the human eye, such as a non-toxic plastic, for example, polymethylmethacrylate.

The lens 1 includes a medial, light-focusing, lens body, or optic, 10 having, for example, as seen in FIG. 2, a convex anterior surface 10a and a generally flat posterior surface 10b, each in a plane generally transverse to the optical axis "0" of the lens body 10. According to the present invention, lens 1 further includes position-fixation means having a pair of opposed curved position-fixation members 21, 22 which are preferably resilient filaments of PMMA, or similar material, intergrally connected with the lens body.

The lens body 10 is preferably round and the position-fixation members 21, 22 are preferably connected to opposite peripheral regions of such lens body so as to extend in generally diametrically opposite directions.

The lens 1 preferably further includes a bore, or positioning hole, 30 preferably located in a peripheral region of the optic 10 and extending thru the lens body from the anterior surface 10a to the posterior surface 10b thereof, forming a thruopening in the lens body. In use, the lens 1 is inserted through the cornea incision 12 (see FIG. 4) in conventional manner. Inside the eye, the lens is manipulated in conventional manner by use of a conventional surgical instrument having a hooked-pointed tip which may also be inserted through the incision 12. After the tip of the instrument is received in bore 30 of the lens 1, the surgeon moves the instrument to manipulate the lens within the eye for proper seating thereof in the manner indicated in FIG. 4.

As seen in FIGS. 1, 2 and 3 bore 30 is preferably in the form of a cylindrical "thrubore" having cylindrical walls 30a extending generally parallel to the optical axis "0". According to a preferred embodiment of the present invention, there is provided a preferably generally cylindrical plug member 40 incorporating masking means in a form to be described below, and having axially opposed transverse end walls 40a, 40b .

FIG. 4 illustrates the lens according to a preferred embodiment, seated in the anterior chamber of the eye, with bore 30 generally parallel to the optical axis "0" and illustrating that, particularly if the lens 1 were to become decentered, the bore 30 is in the path of the light rays entering through the cornea and being focused by lens body 10 on the retina.

Positioning hole 30 would normally be filled with the fluid in the eye with the above described glare effect as a result. According to the invention, glare elimination or at least, reduction, is achieved by providing plug 40 with masking means and inserting such plug in the bore 30 preferably extending from the anterior surface 10a of the lens body 10 to the posterior surface 10b. The masking means is preferably incorporated in plug 40 by making the latter translucent, i.e. semi-opaque or opaque by any of a number of different processes. For example, an opaque coating may be applied to one or both end faces 40a, 40b or one or both such faces may be etched to a rough finish, or it may be sufficient to leave one or the other of such faces unground or at least not optically smooth. Finally, the plug 40 may be made of a material which is pigmented, or otherwise not transparent.

FIGS. 5 and 6 illustrate another preferred embodiment in which the plug means is a plug 41 having a threaded shank 41a and a head 41b further illustrated in FIG. 9a and described below. Plug 41 is threadedly received in positioning hole 30a which preferably has a female thread adapted to receive the male thread of the shank 41a.

FIGS. 7 and 8 illustrate a still further preferred embodiment of the present invention, namely, one in which an optic 10 cooperates with a plug 42 partially inserted in the bore 30 of the optic. The lens is preferably inserted into the eye in this assembled condition. The portion of the bore 30 which is still open i.e. the anterior portion is used as the positioning hole and after the lens is manipulated into proper seating position, a plier-like surgical tool may be used to press the plug 42 the remainder of the way into the bore 30. Plug 42 is preferably of the type illustrated in FIG. 9c and described below.

The masking means incorporated in the plug 40, 41, 42 prevents light rays from passing therethrough or, at least, from passing therethrough in undiffused form. Thus, light rays refracted in a region exhibiting one index of refraction will not be adjacent to light rays refracted in a region exhibiting another index of refraction, since the positioning hole, instead of being filled with transparent fluid will, in accordance with the present invention be filled with a plug which is at least semi-opaque.

Of course, the masking means need not be located on the surface of the plug, but could instead be located elsewhere in the plug, so long as such masking means is in the path of the light rays in question. If the material of the plug itself comprises the masking means, such material is preferably pigmented with a dark blue color to form an opaque or translucent material, and such opaque or semi-opaque coloring could extend throughout the material of the entire plug.

According to a preferred embodiment of the present invention a plug means such as plug 40 is adapted to be inserted into and releasably retained in positioning hole 30. The plug means 40 preferably, though not necessarily, is comprised of a material which is the same as the material of the optic portion of the lens, for example, PMMA or Prolene. Preferably, the plug means has a cylindrical body adapted to be pressed or screwed into the positioning hole 30 for substantially filling the latter. Thus, according to one embodiment of the present invention, the plug means 40 is in the form of a cylindrical plug 41 which, as seen in FIG. 9c has an outer surface having a diameter only slightly larger than the diameter of the positioning hole 30 in the optic so as to be capable of being press-fitted therein. As is well known, a diameter difference of only one or two ten-thousandths of an inch suffices for this purpose.

Alternatively, the plug means may be in the form of a plug 43, which, as seen in FIG. 9b has a substantially cylindrical but slightly conical outer surface. Preferably, in such construction, the smaller diameter of such conical surface is only slightly smaller than the diameter of the positioning hole while the diameter of the conical surface at the larger axial end thereof is only slightly larger than the diameter of the positioning hole. Typically, such positioning holes have a diameter of 0.3 mm or 0.5 mm. The plug means 40, 43 preferably have a pair of axially opposed end faces the shape of whose surfaces preferably corresponds generally to the shape of the respective surface of the optic of surrounding the positioning hole. Thus end face 40 a will, in the illustrated embodiment, have a convexly shaped surface corresponding to the convex shape of the anterior surface of the optic 10 in the region surrounding the positioning hole 30 while the other end face, 40b will be generally flat so as to correspond to the surface of the optic portion surrounding the positioning hole at the posterior side 10b of the optic. The axial length of plug 40, 43 and the length of shank 41a is preferably substantially equal to the length of the axial dimension of the positioning hole 30.

It will be understood that in accordance with a still further embodiment of the present invention the head portion 41b may extend only axially and need not include a radially extending collar in order to be able to be grasped by the appropriate surgical instrument. Those plug embodiments which do not have a head portion can be inserted and/or removed from the positioning hole by a plier-like surgical instrument, capable of supporting one face of the lens with one jaw part while pressing the plug into the positioning hole with the other jaw part. Similarly, removal of a plug such as plug 40, from the positioning hole, should such ever be required for repositioning of the lens within the eye, can be accomplished with a plier-like instrument having a first jaw part with a projection similar in shape to the plug but of smaller diameter and adapted to push against one axial end face of the plug while the other jaw part is adapted to support the corresponding face of the optic while the projecting portion of the other jaw pushes the plug through the positioning hole and into a corresponding hole in such other jaw part of the surgical instrument.

While preferred materials for the plug are PMMA or Prolene, it will be understood that any other materials compatible with the interior of the human eye and of sufficient stiffness to be capable of insertion and removal into and out of a positioning hole in an optic and compatible with the material of such optic, may be used. Preferably the material used is "dark blue PMMA" or "dark blue Prolene" both of which are materials which are tinted a dark blue color throughout. Alternatively an optically transparent material may be used and the end walls of the plug may be coated with an opaque or at least a semi-opaque material. Semi-opaqueness may be obtained by leaving one or both of the end faces of the plug in an unfinished, i.e. in unground condition, so that light rays striking such surface will be diffused and will not be transmitted to the retina in recognizable form.

In use, the lens seen in FIG. 4 will be implemented for seating within the eye by use of the positioning hole 30. Thereafter, the tip of the positioning instrument is removed from the positioning hole and a plug means such as plug 40, 41, 43 is inserted into the eye through the corneo-scleral incision 12 and held in position adjacent one end of the positioning hole and in axial alignment therewith. Thereafter, the plug is pressed, or threaded, into the positioning hole until it is securely, but releasably, retained therein.

Alternatively, the plug means may be partly inserted in a positioning hole prior to insertion of the lens into the eye. The lens, with the partly inserted plug means, is then seated in the eye using, for the positioning instrument, the portion 30b of the positioning hole which remains unobstructed. After the lens has been properly seated in the eye and the surgical instrument used for seating has been withdrawn from the positioning hole, the plug means is forced the remainder of the way into the positioning hole substantially filling the latter. According to this latter method, the difficulty of aligning the plug means with the positioning hole in the eye is avoided.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.