Phakic intraocular lens for correction of astigmatism in keratoconus

Abstract

A phakic intraocular lens for the correction of complex astigmatism in keratoconus, containing an optical zone of the lens located on the optical axis of the lens, holes located on it for the circulation of intraocular fluid, a fixation zone around the optical zone, differs in that it additionally has an absolutely opaque disk placed in the optical center, in the center of which there is a hole. In addition, the lens with these elements is made of various biologically compatible materials by simultaneous molding.

Description

[0001] PHAKIC INTRAOCULAR LENS FOR CORRECTION OF ASTIGMATISM IN KERATOCONUS

[0002] The present invention relates to the field of ophthalmology, namely to the correction of the phakic intraocular lens in ophthalmology and is used to improve vision.

[0003] Keratoconus is an eye condition in which your cornea — the clear, dome-shaped front of your eye — gets thinner and gradually bulges outward into a cone shape. Most often, the patient complains of decreased vision at long distances, frequent changes of glasses and the appearance of a "halo" around the light source. The disease begins mainly at the age of 16-18 years and its progress stops at the age of 35-40 years.

[0004] According to the International Keratoconus Foundation, there are 3 to 5 cases of keratoconus for every 1,000 people in the world.

[0005] The exact etiology of this disease is unknown, but risk factors include genetics and living in places with high levels of ultraviolet radiation.

[0006] Keratoconus treatment consists of two stages - the first is to stop the progression of keratoconus, the second is to improve vision. After stabilization of the disease, a phakic lens can be implanted to correct vision, although in some cases, due to complex astigmatism in patients diagnosed with keratoconus, visual acuity improves only with the help of a pinhole occluder.

[0007] An implantable collamer lens (I CL) consisting of optical and tactile (supporting) parts was chosen as the prototype of the invention. Figure I shows an ICL manufactured by the American company STAAR, which is used to correct high refractive errors. The disadvantage of ICL, currently available on the market, is that it is not able to correct astigmatism with complex displacement in patients in whom complete correction is achieved only with the help of a pinhole occluder. In such patients, a few months after the ICL is placed, a lens with an opaque disk in the center with a hole in the middle is placed to in the thickness of the cornea.

[0008] An implantable collamer lens (ICL) is an artificial lens that is implanted in the eye for many years. It is used to correct myopia, hyperopia and astigmatism. ICL allows you to effectively get rid of the need for glasses or contact lenses. It is also a safe alternative for patients for whom laser correction is not suitable due to corneal pathologies or the presence of a large refractive error. This is a phakic intraocular lens, that is, an artificial lens is placed in the eye without removing the natural lens. ICL is made from a mixture of plastic and collagen called a collamer.

[0009] The implantation of a phakic lens is carried out by minimally invasive surgery (MIS) between iris and a natural lens.

[0010] The pinhole occluder is also known — an opaque disk with one or more small holes. It is used to assess visual acuity. This is an easy way to focus light rays, which can temporarily eliminate or minimize a visual defect caused by a refractive error (for example, astigmatism). When using a pinhole occluder, light will pass only through the center of the optical sections, so the effect of corneal defects is practically zero. In addition, before surgery, the doctor is given the opportunity to predict the expected visual acuity.

[0011] Source: Cornea: Fundamentals, Diagnosis and Treatment, Edition 4, Mannis M.J., Holland E.J., 2022, Elsevier.

[0012] To eliminate this disadvantage, the proposed invention provides for the simultaneous molding of a phakic lens from a material in which the optical center is closed by an absolutely opaque disk, and such a design is obtained by simultaneous molding of the lens. The present invention provides a phakic lens design that allows you to get the desired result in one operation instead of two. With modern methods, the patient would have to undergo surgery twice - first for implantation of a phakic lens, and then, after a few months, for implantation of a stenosing occluder lens into the thickness of the cornea.

[0013] A phakic intraocular lens for the correction of myopia and astigmatism in keratoconus is proposed, containing the optical zone of the lens located on the optical axis of the lens, holes located on it for the circulation of intraocular fluid, a fixation zone around the optical zone, in addition, an absolutely opaque disk with a hole located in the center. In addition, the lens with these elements is made of various biologically compatible materials by simultaneous molding.

[0014] Fig. 1 shows an ICL lens manufactured by the American company VISIAN.

[0015] Fig. 2 shows a diagram of the proposed design of a phakic lens, in the optical center of which there is a hole (1), a ring (2) made of a totally opaque material with an optical zone (3) around it and a haptic support (4) around the optical zone.

[0016] The proposed invention in the manufacture of the lens body provides for the formation of a lens in one step in the form of a single shape from a collamer and polyvinylidene fluoride; however, other suitable biocompatible materials can be used.

[0017] The lens is manufactured in one step, as a whole, using precision casting methods.

[0018] The lens body will be made of a collamer, and the diaphragm around the pinhole will be made of polyvinylidene fluoride. The collamer is heated on a special device, in the center of which polyvinylidene fluoride is poured in a circle. Then, with a sharp pointed tool, the contour of the lens body is cut out, 5 small holes are cut for the circulation of aqueous humour, the lens is placed in a low-temperature saline solution and thoroughly rinsed for 30 minutes. After this time, the lens is coated with special solutions that improve its optical characteristics and biocompatibility. A coating of a hydrophobic solution prevents water droplets from the delay to the lens surface. Strict quality control measures are applied in the production process. This includes verification, optical testing and validation to ensure that each lens meets international standards.

[0019] After manufacturing, the lenses are sterilized to eliminate any possible contamination. Gamma radiation or ethylene oxide is used during sterilization. After sterilization, the lenses are packed in a sterile container to preserve sterility until implantation. The container is placed in a cardboard box with the data of the lens manufacturer, the diopter strength of the lens, the date of manufacture and expiration date, as well as the serial number.

Claims

The ClaimsA phakic intraocular lens for the correction of complex astigmatism in keratoconus, containing an optical zone of the lens located on the optical axis of the lens, holes located on it for the circulation of intraocular fluid, a fixation zone around the optical zone, differs in that it additionally has an absolutely opaque disk placed in the optical center, in the center of which there is a hole. In addition, the lens with these elements is made of various biologically compatible materials by simultaneous molding.

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