Haptic component of a composite intraocular lens

Abstract

The invention relates to ophthalmology. The technical result is that of making a haptic component less labour-intensive to produce and easier to use. A haptic component of a composite intraocular lens is proposed which comprises a base for an optical part, said base being integrally connected to two oppositely arranged support elements, wherein the support elements have a rectangular profile in cross-section and the base for the optical part is in the form of a flat ring having an outer edge and an inner edge, with a rim along the outer edge and a U-shaped slot in the region of each support element, said U-shaped slot being formed by a radial projection that extends from the rim toward the centre, parallel to the plane of the ring, and overlaps the inner edge of the ring.

Description

Haptic component of an intraocular lens assembly

[0001] The invention relates to ophthalmology, and more specifically to prefabricated intraocular lenses consisting of two parts (optical and haptic), intended for intraocular correction of aphakia.

[0002] The human eye provides vision by transmitting light and refracting it through the cornea and crystalline lens onto the retina. The quality of the focused image depends on many factors, such as the size and shape of the eyeball and the transparency of the cornea and crystalline lens. If the crystalline lens loses its transparency due to aging, disease, genetic defects, or harmful external influences, visual function is impaired because the cloudy lens blocks and scatters light. This lens damage is known as a cataract. The common treatment for cataracts is surgical removal of the cloudy lens and its functional replacement with an intraocular lens (IOL).

[0003] Improving the accuracy of IOL power calculations remains a significant challenge in modern intraocular correction. To achieve the planned visual outcome, the surgeon must individually select the IOL power for the patient to ensure maximum visual function in the postoperative period without the need for additional glasses or contact lenses. Standardization and refinement of surgical techniques, increased accuracy of diagnostic equipment, and advances in the development of more sophisticated formulas for calculating IOL power, including those using neural network algorithms, have significantly improved the accuracy of refractive results. For example, the probability of achieving a result within 0.5 diopters of the planned refractive target in eyes without complications in IOL power calculations exceeds 80% in many studies.However, the more than 20 million IOL implantations performed annually worldwide represent a highly heterogeneous population. In particular, patients with significant deviations from standard values ​​for the anteroposterior axis length, following previous keratorefractive surgeries, and requiring immediate keratoplasty present particular challenges in calculating IOL power and often experience unsatisfactory refractive results. Furthermore, there are certain categories of patients whose clinical refraction is unstable and fluctuates widely: this is observed in eyes with silicone tamponade in the vitreous cavity. These examples highlight the need to find ways to adjust clinical refraction after primary IOL implantation.

[0004] The following methods for solving the problem were previously proposed.

[0005] Photoadjustable IOL. Non-invasive correction of IOL power in the postoperative period within 2-3 diopters for both spherical and cylindrical refractive components is possible through the use of a special chemical composition of the optical material, susceptible to structural changes under the influence of ultraviolet irradiation (US Patent US-6450642-B1). Fundamental disadvantages of this approach include the limited scope of corrective action, its single-use nature, and its feasibility on a specific IOL model.

[0006] IOL Refractive Index Modification. Another relatively noninvasive method for postoperative correction of the implant's optical properties, which has not yet reached clinical application, is based on the use of photodestructive laser radiation, which modifies the IOL's refractive index (US Patent US-8292952-B2). Modifying the IOL's optics somewhat increases light scattering and the loss of modulation transfer function.

[0007] IOL replacement. In clinical practice, this is the default solution; it doesn't require specialized technology and depends solely on surgical expertise. The radical nature of this solution is limited by the risk of complications, especially in the late postoperative period, following fibrosis of the capsular bag around the implant, leading to its tight adhesion.

[0008] Implantation of an additional IOL. When the target refraction cannot be achieved with a single lens, or when the result of the primary implantation needs to be corrected, an additional IOL provides a highly predictable and relatively safe solution (US Patent US-10004592-B2). This method cannot claim universality, as it is not without fundamental drawbacks, including the need for basal iridectomy to prevent pupillary block, as well as implant placement in the ciliary sulcus, outside the safe environment of the capsular bag, with the associated risk of inflammatory and hydrodynamic complications.

[0009] Assembled IOLs. The physical separation of the haptic and optic components in the IOL design helps reduce the surgical risks of replacing the latter by allowing the haptic component of the device to be preserved in the fibrous capsular bag without compromising the integrity of the capsule and zonular apparatus, which are critical for long-term biocompatibility of the implant (RU2629543, RU2283065, RU2281728, RU2281729, RU2281730, RU2283066, RU2281727, RU2281725, RU2283067, RU2281067, RU2283067, RU2294174, RU2281723, RU2294175, RU2550002, US8663235B2, WO2005013850A2, DE102007053224A1, WO2016122805A1, US20160058553A1).

[0010] A prefabricated intraocular lens (IOL) is known from the prior art, as described in patent RU2629543, priority dated October 6, 2016, IPC A61F2 / 16. This device optimizes clinical refraction in a growing child's eye during a critical period of visual system development and reduces ocular tissue trauma during primary and secondary surgeries by preserving the haptic component within the capsular bag.

[0011] The known device comprises an optical component with a diameter no greater than 5.0 mm and a haptic component formed as a closed ring with two equally spaced loops and a total diameter of 9-11 mm. The haptic component serves as a support for the optical portion, which is secured by a continuous projection along the rear edge of the ring and grooves formed by two or three petal-shaped projections along the front edge. The known haptic component is considered the closest analogue. According to the description and graphic material of invention RU2629543, the haptic component has a rounded cross-section, specifically, the support elements at the free end have a circular cross-section. The support for securing the optical component has a rounded cross-section along the perimeter, and the grooves have a C-shaped cross-section. It is assumed that a product with this profile can be produced by mechanical turning.A disadvantage of the known device is its complexity, as it requires special machine reconfiguration requirements when forming grooves. The known device is also limited for use in adult patients due to its small size of 9-11 mm. This overall size of the IOL assembly will lead to its decentration in the capsular bag of an adult patient's eye, dislocation of the haptic loop into the anterior chamber, and pupillary entrapment. Assembling the haptic component with the optic for joint operation is also challenging due to the misalignment of the petals and support elements. The surgeon secures the haptic component to the assembly surface by pressing on the attachment point of the support element to the haptic ring. When lifting the petal-shaped protrusion and sliding the edge of the optic component under it, unwanted displacement / oscillation of the haptic ring along the assembly surface may occur due to the elasticity of the haptic component material.

[0012] The aim of the present invention is to improve the closest analogue and eliminate its indicated disadvantages.

[0013] The technical result is a reduction in the labor intensity of manufacturing the haptic component with the possibility of its use in adult patients, and an increase in ease of use.

[0014] The technical result is achieved in that a haptic component of a prefabricated intraocular lens is proposed, comprising a base for the optical part, monolithically connected to two oppositely located support elements, wherein the support elements have a rectangular profile in cross-section, and the base for the optical part is a flat ring with an outer and inner edge, which contains a rim along the outer edge, and in the area of ​​each support element contains a U-shaped groove formed by a radial protrusion extending from the rim to the center parallel to the plane of the ring and overlapping the inner edge of the ring.

[0015] The proposed technical solution is explained by the following graphic material.

[0016] [Fig. 1] illustrates the general appearance of the haptic component of the composite IOL.

[0017] illustrates a cross-section of the haptic component of the composite IOL (A-A).

[0018] illustrates a cross-section of the haptic component of the composite IOL (B-B).

[0019] illustrates a cross-section of the haptic component of the composite IOL (C-C).

[0020] illustrates a type of optical component designed to work in conjunction with the proposed haptic component in an IOL assembly.

[0021] illustrates the appearance of the assembled IOL (haptic component and optic component assembly).

[0022] The haptic component 1 of the prefabricated intraocular lens comprises a base 2 which is monolithically connected to two oppositely located support elements 3. The base 2 is intended for placement of the optical component 4. The base 2 is a flat ring 5 with an outer edge 6 and an inner edge 7 which contains a rim 8 along the outer edge 6, and in the area of ​​each support element 3 contains a U-shaped groove 9 formed by a radial projection 10 extending from the rim 8 to the center parallel to the plane of the ring 5. The support elements 3 have a rectangular profile in cross-section, as shown in . The proposed haptic component 1 is intended for joint use with the optical component 4. The haptic component 1 has a total diameter of 11.0-13.0 mm, which allows it to be used as part of an prefabricated IOL for adult patients.Compared to its closest analogue, these dimensions correspond to the parameters of an adult patient's eye and ensure stable stabilization of the haptic component in the capsular bag and prevent its decentration during use. The diameter of optical component 4 is predominantly 5.5-6.0 mm, which corresponds to the average pupil diameter for individuals aged 20-50 years under mesopic conditions. The dimensions of base 2 for positioning optical component 4 are selected such that, during IOL assembly, the edge of optical component 4 fits into grooves 9 and extends approximately 0.2 mm from bead 8. Radial projection 10 overlaps the inner edge 7 of the ring. This design of the proposed haptic component 1 ensures secure retention of optical component 4 and stabilizes haptic component 1 in the capsular bag during use of the assembled IOL.The gap between the edge 8 and the edge of the optical component 4 allows the surgeon to hook it with an instrument (hook) during reimplantation, and also to rotate the optical component 4 when installing the prefabricated IOL.

[0023] In the first method, the proposed haptic component can be manufactured as follows. A finished product with the specified shape and dimensions is obtained by curing a liquid photopolymer material under light between two glass plates, each with a transparent pattern applied to a background of opaque material (a photomask). Specifically, the glass plate is designed with areas transparent and opaque to UV light, such as chrome, the negative image of which corresponds to the flat image of the specified layer of the haptic component. The photopolymer material is poured between the glass plates and cured with light. Polymerization of the material does not occur in the opaque areas. The uncured material is then removed. The haptic component is manufactured layer by layer, using multiple photomasks to form the grooves.When forming each layer, a gasket is installed around the perimeter between the glass plates, which determines the thickness of the layer.

[0024] In the second method, the proposed haptic component can be manufactured using layer-by-layer 3D printing. These manufacturing methods produce a haptic component with a rectangular cross-section and a U-shaped groove.

[0025] The proposed manufacturing options do not exclude other manufacturing methods that make it possible to obtain the design of the proposed haptic component described in the present invention.

[0026] The optical component and the proposed haptic component together form a prefabricated IOL, the design of which allows for implantation in an assembled form ex vivo. The IOL is assembled on a sterile surface without the use of liquids or viscoelastic solutions using standard ophthalmic surgical instruments (tying tweezers, Sinskey hook, etc.). One edge of the optical component 4 is inserted into the groove 9 under the radial projection 10. Next, the optical component 4 is placed in the base 2. The IOL assembly is completed by placing the opposite edge of the optical component 4 under the opposite groove 9 under the second radial projection 10. To do this, simply lift the radial projection 10, insert the edge of the optical component 4 into the groove, and return the radial projection 10 to its original position. The location of the U-shaped grooves 9 in the area of ​​the support elements 3 has an advantage over the closest analogue.When optical component 4 is inserted into slot 9, the surgeon secures haptic component 1 to support element 3, pressing it against the assembly surface. The secured support element 3 counteracts optical component 4, pushing support element 3 away from itself. In this case, slots 9 are conveniently positioned coaxially to the applied mechanical force, simplifying the assembly of haptic component 1 with optic component 4. This eliminates unwanted displacement of base 2 along the surface during IOL assembly.

[0027] After assembly, the IOL assembly is placed into the working portion of the injection system cartridge, pre-moistened with a layer of methylcellulose-based viscoelastic. The haptic component is placed into the cartridge with the radial projections facing upward—this is the orientation in which the device should be positioned in the eye. The leading support element is left as is, and the trailing support element is folded over the optic component to minimize the risk of damage when passing through the narrow section of the injector. The injector wings are folded. A visual inspection is performed to ensure that the IOL is not pinched between the wings. If the visual inspection is satisfactory, the cartridge is placed into the injector.

[0028] Implantation is performed through a 2.2-2.4 mm corneal or corneoscleral incision. With the bimanual technique, assistance can be provided with an auxiliary instrument inserted into the anterior chamber via a corneal paracentesis. After insertion of the IOL into the anterior chamber, both supporting elements of the haptic component are positioned within the capsular vaults. In cases of miosis, intracapsular positioning of the supporting elements is mandatory. Upon completion of the implantation, the surgeon verifies the correct placement of the haptic component and the correct positioning of the optic component within the bed between the posterior cornice and the fixation petals. The final stages of the surgery are the same as those used by the surgeon for monolithic IOL implantation. Alternatively, separate sequential implantation of the components and subsequent intraocular assembly are possible.However, preference is given to extraocular assembly to minimize manipulation in the anterior chamber.

Claims

A haptic component of a prefabricated intraocular lens comprising a base for the optical portion, monolithically connected to two oppositely located support elements, characterized in that the support elements have a rectangular profile in cross-section, and the base for the optical portion is a flat ring with an outer and inner edge, which contains a rim along the outer edge, and in the area of ​​each support element contains a U-shaped groove formed by a radial projection extending from the rim to the center and parallel to the plane of the ring and overlapping the inner edge of the ring. The haptic component of the prefabricated intraocular lens according to claim 1, characterized in that it has a total diameter of 11.0-13.0 mm.

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