Patent Description:
Visually impairing cataract, or clouding of the lens, is the leading cause of preventable blindness in the world. Presently, cataracts are treated by surgical removal of the affected lens and replacement with an artificial intraocular lens ("IOL"). <FIG> is a diagram of an eye <NUM> illustrating anatomical structures related to the surgical removal of a cataract and the implantation of an IOL. The eye <NUM> comprises an opacified lens <NUM>, an optically clear cornea <NUM>, and an iris <NUM>. A lens capsule (capsular bag <NUM>) located behind the iris <NUM> of the eye <NUM> contains the opacified lens <NUM>. More particularly, the opacified lens <NUM> is seated between an anterior capsule segment (anterior capsule <NUM>) and a posterior capsular segment (posterior capsule <NUM>). The anterior capsule <NUM> and the posterior capsule <NUM> meet at an equatorial region <NUM> of the capsular bag <NUM>. The eye <NUM> also comprises an anterior chamber <NUM> located in front of the iris <NUM> and a posterior chamber <NUM> located between the iris <NUM> and the capsular bag <NUM>.

A common technique for cataract surgery is extracapsular cataract extraction ("ECCE"), which involves the creation of an incision near the outer edge of the cornea <NUM> and an opening in the anterior capsule <NUM> (i.e., an anterior capsulotomy) through which the opacified lens <NUM> is removed. The lens <NUM> can be removed by various known methods. One such method is phacoemulsification, in which ultrasonic energy is applied to the lens to break it into small pieces that are aspirated from the capsular bag <NUM>. Thus, with the exception of the portion of the anterior capsule <NUM> that is removed in order to gain access to the lens <NUM>, the capsular bag <NUM> may remain substantially intact throughout an ECCE. The intact posterior capsule <NUM> provides a support for the IOL and acts as a barrier to the vitreous humor within the posterior chamber <NUM> of the eye <NUM>. Following removal of the opacified lens <NUM>, an artificial IOL, which may be designed to mimic the transparency and refractive function of a healthy lens, is typically implanted within the capsular bag <NUM> through the opening in the anterior capsule <NUM>. The IOL may be acted on by the zonular forces exerted by a ciliary body <NUM> and attached zonules <NUM> surrounding the periphery of the capsular bag <NUM>. The ciliary body <NUM> and the zonules <NUM> anchor the capsular bag <NUM> in place and facilitate accommodation, the process by which the eye <NUM> changes optical power to maintain a clear focus on an image as its distance varies.

A frequent complication of ECCE and other forms of cataract surgery is opacification of the posterior capsule <NUM>. Posterior capsule opacification ("PCO") results from the migration of residual lens epithelial cells from the equatorial region <NUM> of the capsular bag <NUM> toward the center of the posterior capsule <NUM>. One factor contributing to the development of PCO is contact between the IOL and the surface of the posterior capsule <NUM>. Subsequent to ECCE, the lens epithelial cells may proliferate between the IOL and the surface of the posterior capsule <NUM>, leading to wrinkling and clouding of the normally clear posterior capsule <NUM>. If clouding of the posterior lens capsule <NUM> occurs within the visual axis, then the patient will experience a decrease in visual acuity and may require additional surgery to correct the patient's vision.

A widely utilized procedure to clear the visual axis of PCO is Neodymium: Yttrium-Aluminum-Garnet ("Nd/YAG") laser capsulotomy, in which a laser beam is used to create an opening in the center of the cloudy posterior capsule <NUM>. However, Nd/YAG laser capsulotomy exposes patients to the risk of severe complications that can lead to significant visual impairment or loss, such as retinal detachment, papillary block glaucoma, iris hemorrhage, uveitis/vitritis, and cystoid macula edema. Moreover, the laser energy is ordinarily directed though the IOL, which may damage the optics of the implant or disrupt its placement within the capsular bag <NUM>. Accordingly, there exists a need to prevent the occurrence of PCO rather than treating PCO at a later date after implantation of an IOL.

Reference is made to <CIT>, <CIT>, <CIT>. <CIT>, <CIT> and <CIT> which have been cited as representative of the state of the art.

It will be appreciated that the scope of the invention is in accordance with the claims. Accordingly, there is provided a capsular ring in accordance with claim <NUM>. Further features are provided in the dependent claims.

The present disclosure concerns an asymmetric capsular ring designed to inhibit PCO and facilitate safe insertion of a lens once implanted in the capsular bag of a patient's eye. In certain embodiments, a capsular ring for insertion into a capsular bag of a patient's eye includes an anterior ring defining a first opening and having a first cross-sectional width and a posterior ring defining a second opening and having a second cross-sectional width. A diameter of the first opening is greater than a diameter of the second opening, and the second cross-sectional width is greater that the first cross-sectional width. The capsular ring further includes a sidewall connecting the first ring and the second ring, the sidewall comprising a plurality of orifices spaced circumferentially around the sidewall.

Once inserted into the capsular bag of a patient's eye, the above described capsular ring may inhibit PCO by (<NUM>) keeping the capsular bag open to facilitate circulation of aqueous humor into the capsular bag, and (<NUM>) engaging the equatorial region of the capsular bag in a manner that inhibits migrations of lens epithelial cells from the equatorial region. In addition, the asymmetric design of the capsular ring (i.e., the posterior ring being greater in width than the anterior ring) may facilitate safe insertion of a lens by helping to guide one or more haptics of the lens into a proper plane (between the posterior and anterior rings) rather than an area of the capsular bag posterior to the capsular ring.

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numerals indicate like features and wherein:.

The skilled person in the art will understand that the drawings, described below, are for illustration purposes only. The drawings are not intended to limit the scope of the applicant's disclosure in any way.

It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described systems, devices, and methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the systems, devices, and/or methods described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts.

In general, the present disclosure relates to an asymmetric capsular ring designed to inhibit PCO and facilitate safe insertion of a lens once implanted in the capsular bag of a patient's eye. In some instances, embodiments of the present disclosure comprise a capsular ring constructed of an anterior ring and a posterior ring connected by a sidewall, the posterior ring being greater in width than the anterior ring. Once inserted into the capsular bag of a patient's eye, the capsular ring may inhibit PCO by (<NUM>) keeping the capsular bag open to facilitate circulation of aqueous humor into the capsular bag, and (<NUM>) engaging the equatorial region of the capsular bag in a manner that inhibits migrations of lens epithelial cells from the equatorial region. In addition, the asymmetric design of the capsular ring (i.e., the posterior ring being greater in width than the anterior ring) may facilitate safe insertion of a lens by helping to guide one or more haptics of the lens into a proper plane (between the posterior and anterior rings) rather than an area of the capsular bag posterior to the capsular ring.

<FIG> illustrate an exemplary asymmetric capsular ring <NUM>, according to certain embodiments of the present disclosure. Capsular ring <NUM> may include an anterior ring <NUM> and a posterior ring <NUM>, and the anterior ring <NUM> may be coupled to the posterior ring <NUM> via a sidewall <NUM>. As used herein, the terms "anterior" and "posterior" refer to relative positions along the visual axis when implanted in the capsular bag of an eye <NUM>.

Anterior ring <NUM>, when in the depicted expanded (i.e., unstressed) position, may define a generally circular central opening <NUM> having a diameter <NUM>. Additionally, anterior ring <NUM> may have a generally rectangular cross section having a width <NUM>. Similarly, posterior ring <NUM>, when in the depicted expanded (i.e., unstressed) position, may define a generally circular central opening <NUM> having a diameter <NUM> and may have a generally rectangular cross section having a width <NUM>.

In certain embodiments, the width <NUM> of posterior ring <NUM> may be greater than the width <NUM> of anterior ring <NUM>. Moreover, anterior ring <NUM> and posterior ring <NUM> may have substantially the same outer diameter and may be coupled to one another (via sidewall <NUM>, discussed below) such that the outer edges anterior ring <NUM> and posterior ring <NUM> generally align (as depicted in <FIG>). As a result, diameter <NUM> of opening <NUM> defined by anterior ring <NUM> may be greater than the diameter <NUM> of opening <NUM> defined by posterior ring <NUM>.

Although anterior ring <NUM> and posterior ring <NUM> are each depicted and described as having a rectangular cross section, the present disclosure contemplates that anterior ring <NUM> and posterior ring <NUM> may each have any suitable cross-sectional shape with the width <NUM> of posterior ring <NUM> being greater than the width <NUM> of anterior ring <NUM>. For example, in certain embodiments, posterior ring <NUM> may comprise a rectangular cross section that additionally includes one or more raised portions (e.g., bumps) on its anterior surface. These raised portions may help reduce friction between the anterior surface of posterior ring <NUM> and a lens engaged with capsular ring <NUM> (as discussed with regard to <FIG>, below).

Sidewall <NUM> may couple anterior ring <NUM> to posterior ring <NUM> in the above-described configuration. According to the invention, sidewall <NUM> has an outer diameter less than the outer diameter of anterior ring <NUM> and posterior ring <NUM> such that, when implanted in the capsular bag <NUM> of a patient's eye <NUM>, an equatorial void is created in the equatorial region <NUM> of the capsular bag <NUM> (as described in further detail below). Additionally, sidewall <NUM> includes a plurality of orifices <NUM> spaced circumferentially around sidewall <NUM>. When capsular ring <NUM> is implanted in the capsular bag <NUM> of a patient's eye <NUM>, orifices <NUM> may allow aqueous humor from anterior chamber <NUM> to circulate within the equatorial void created by capsular ring <NUM> (as described in further detail below).

In certain examples, not forming a part of the invention, sidewall <NUM> may define a generally flat outer profile (as illustrated in <FIG>). According to the invention, sidewall <NUM> defines a generally concave outer profile. For example, <FIG> illustrate a configuration of asymmetric capsular ring <NUM> in which sidewall <NUM> defines a generally concave outer profile. Although sidewall <NUM> is depicted and described as particular outer profile shapes for exemplary purposes, the present disclosure contemplates that sidewall <NUM> may define any suitable outer profile shape, according to particular needs.

Although anterior ring <NUM>, posterior ring <NUM>, and sidewall <NUM> are described above as distinct components coupled together for simplicity, according to the invention, the anterior ring <NUM>, posterior ring <NUM>, and sidewall <NUM> are each regions of a single unitary structure. In other words, the present disclosure contemplates that anterior ring <NUM>, posterior ring <NUM>, and sidewall <NUM> may each be separately formed components that are fused together in any suitable manner or that capsular ring may be formed as a unitary component with anterior ring <NUM>, posterior ring <NUM>, and sidewall <NUM> referencing different portions of that unitary component.

Capsular ring <NUM> may be constructed from a structurally deformable biocompatible material or combination of such materials, enabling capsular ring <NUM> to elastically or plastically deform without compromising its integrity. For example, capsular ring <NUM> may be made from a self-expanding biocompatible material, such as Nitinol. As another example, capsular ring <NUM> may be made from a resilient polymer, such as silicone or <NUM>-phenyl ethyl acrylate and <NUM>-pheylethyl methacrylate known under the name AcrySof®. As yet another example, capsular ring <NUM> may be made from an elastically compressed spring temper biocompatible material. Other materials having shape memory characteristics may also be used. In certain embodiments, the material composition of capsular ring <NUM> resiliently biases the ring toward the expanded condition.

The above-discussed structurally deformable materials may allow capsular ring <NUM> to be restrained in a low profile configuration during delivery into the eye and to resume and maintain its expanded shape in vivo after the delivery process. For example, <FIG> illustrates an example mechanism for inserting capsular ring <NUM> into the capsular bag <NUM> of a patient's eye <NUM>, according to certain embodiments of the present disclosure. The capsular bag <NUM> of eye <NUM> is shown with an anterior capsulorhexis <NUM> (i.e., an area of the anterior capsule <NUM> that has been removed) and with the natural lens removed. As a result, an incision <NUM> in the cornea <NUM> may allow for the insertion of capsular ring <NUM> into capsular bag <NUM> via incision <NUM> and anterior capsulorhexis <NUM>.

In certain embodiments, capsular ring <NUM> may be inserted into the capsular bag <NUM> of a patient's eye <NUM> using a delivery instrument <NUM>. A lumen <NUM> of delivery instrument <NUM> may be inserted through corneal incision <NUM> (e.g., a <NUM>-<NUM> incision), through anterior capsulorhexis <NUM>, and into the capsular bag <NUM>. Capsular ring <NUM> may be housed in the lumen <NUM> in a compressed (i.e., unexpanded) state. Delivery instrument <NUM> may include a plunger <NUM> configured to translate longitudinally within lumen <NUM> such that plunger <NUM> may push capsular ring <NUM> out of the distal end of lumen <NUM> and into capsular bag <NUM>. Upon exiting the distal end of lumen <NUM> of delivery instrument <NUM>, capsular ring <NUM> may assume the expanded position and may be located along the equatorial region <NUM> of capsular bag <NUM>.

Although a particular technique for inserting capsular ring <NUM> into the capsular bag <NUM> of a patient's eye <NUM> has been described, the present disclosure contemplates that capsular ring <NUM> may be inserted into the capsular bag <NUM> of a patient's eye <NUM> using any suitable technique, according to particular needs.

<FIG> illustrates a cross-section of capsular ring <NUM> after insertion into the capsular bag <NUM> of a patient's eye <NUM>, according to certain embodiments of the present disclosure. When positioned along the equatorial region <NUM> of capsular bag <NUM>, capsular ring <NUM> may maintain separation between anterior capsule <NUM> and posterior capsule <NUM>. In other words, capsular ring <NUM> may keep capsular bag <NUM> open. As a result, aqueous humor located in the anterior chamber <NUM> may be allowed to circulate through capsular bag <NUM> by passing through anterior capsulorhexis <NUM>. This circulation may help to prevent migration of lens epithelial cells.

In addition to keeping capsular bag <NUM> open, capsular ring <NUM> may create an equatorial void <NUM> when seated along the equatorial region <NUM> of the capsular bag <NUM>. Additionally, equatorial void <NUM> may be bounded by the sharp corners of anterior ring <NUM> and posterior ring <NUM> engaging the capsular bag <NUM>, and these sharp edges may help prevent the migration of lens epithelial cells from the equatorial region <NUM> to other areas of the capsular bag <NUM>. In other words, the equatorial void <NUM> may serve to contain lens epithelial cells.

Additionally, orifices <NUM> is sidewall <NUM> may allow the aqueous humor circulating through capsular bag <NUM> to also circulate within equatorial void <NUM>, further helping to prevent migration of lens epithelial cells. The above discussed ways in which capsular ring <NUM> helps to prevent migration of lens epithelial cells may collectively reduce the likelihood of PCO.

<FIG> illustrates an example IOL system <NUM> including capsular ring <NUM>, according to certain embodiments of the present disclosure. In addition to the capsular ring <NUM>, IOL system <NUM> may include a lens <NUM> configured to interface with capsular ring <NUM>. For example, lens <NUM> may include an optic <NUM> (e.g., any suitable optic for correcting a patient's vision) and one or more haptics <NUM>. In certain embodiments, lens <NUM> may be engaged with capsular ring <NUM> by inserting haptics <NUM> through corresponding orifices <NUM> in the sidewall <NUM> of capsular ring <NUM>. For example, a surgeon may first insert capsular ring <NUM> into the capsular bag <NUM> of a patient's eye <NUM> (as described above). Once the capsular ring <NUM> is seated in the equatorial region <NUM>, the surgeon may then insert the lens <NUM> into the capsular bag <NUM> and feed the haptics <NUM> through corresponding orifices <NUM> in the sidewall <NUM> of capsular ring <NUM> (such that haptics <NUM> extend into the equatorial void <NUM> and engage the equatorial region <NUM> of capsular bag <NUM>). As a result, lens <NUM> may be seated in capsular bag <NUM> within capsular ring <NUM> such that optic <NUM> extends across a visual axis of the patient's eye <NUM>.

Because the posterior ring <NUM> of capsular ring <NUM> may have a greater width than anterior ring <NUM> (as described above), it may be less likely that, upon insertion of lens <NUM>, a haptic <NUM> will be inadvertently extended through opening <NUM> and into the region of capsular bag <NUM> posterior to capsular ring <NUM>. As a result, capsular ring <NUM> may facilitate safer insertion of lens <NUM>.

Although lens <NUM> is depicted and described as having haptics <NUM> that extend through corresponding orifices <NUM> of capsular ring <NUM>, the present disclosure contemplates that IOL system <NUM> may include a lens <NUM> having any suitable haptics <NUM> facilitating interfacing between the lens <NUM> and the capsular ring <NUM>. As just one example, the present disclosure contemplates that lens <NUM> may have one or more haptics <NUM> shaped to sit between anterior ring <NUM> and a posterior ring <NUM> without extending through orifices <NUM> when lens <NUM> is engaged with capsular ring <NUM>.

Claim 1:
A capsular ring (<NUM>) for insertion into a capsular bag of a patient's eye, the capsular ring comprising:
an anterior ring (<NUM>) defining a first opening and having a first cross-sectional width;
a posterior ring (<NUM>) defining a second opening and having a second cross-sectional width, wherein:
a diameter of the first opening is greater than a diameter of the second opening; and
the second cross-sectional width is greater than the first cross-sectional width; and
a sidewall (<NUM>) connecting the anterior ring (<NUM>) and the posterior ring (<NUM>) as regions of a single unitary structure, the sidewall comprising a plurality of orifices (<NUM>) spaced circumferentially around the sidewall, wherein
an outer diameter of the sidewall (<NUM>) is less than an outer diameter of the anterior ring (<NUM>) and an outer diameter of the posterior ring (<NUM>), such that when implanted into the capsular bag of the patient's eye an equatorial void (<NUM>) is created in an equatorial region of the capsular bag; and
the sidewall (<NUM>) comprises a concave outer profile and a flat inner profile.