The present disclosure relates to treating eyes, and more particularly to devices and methods for forming an adaptive optic in the capsule of a human eye.
People with young healthy eyes can focus on objects at near through a process called accommodation. During accommodation, there is an increase in the optical power of the eye's crystalline lens due to an increase in lens axial thickness, an increase in curvature of the lens anterior and posterior surfaces, and a decrease in lens diameter.
According to the Helmholtz theory of accommodation, when an eye is focused at distance, the circular ciliary muscle is relaxed and the zonules pull on the lens, flattening it. When the eye focuses on a near object, the ciliary muscle contracts, and the lens zonules slacken. With the decreased zonular tension, the lens becomes thicker and more convex. This rounder lens leads to an increase in the dioptric power of the eye, allowing for near vision. In the Helmholtz theory, the zonules are relaxed during accommodation and are under tension when accommodation ends. (Glasser, Adrian. “Accommodation: Mechanism and Measurement,” Ophthalmol Clin N Am, 19 (2006), pp 1-12)
Presbyopia is due to a loss of lens elasticity with age. When the zonules are relaxed during accommodation, the older lens does not change shape to the same degree as the young lens. The aging process of presbyopia can only be reversed by changing the elasticity of the lens or replacing the lens. Thus, there is a need in the art for an apparatus and method which is able to alleviate, reverse, or stop the process described above. The present disclosure may provide a solution for at least one of these remaining challenges.
The subject invention is directed to a new and useful intraocular lens (IOL) that allows for accommodation so that the patient will be able to focus at near, intermediate, and at distance. The intraocular lens includes an outer wall or capsular interface or shell or bag which may be filled. The bag may be compressed, such as by rolling, to a minimum diameter suitable for insertion into an incision at the limbus of the eye (where the cornea meets the sclera) and through an anterior capsulotomy, a circular central opening in the anterior capsule of the crystalline lens. Optimally, the device used to insert the compressed bag will then be used to inject a filling medium into the bag. Alternatively, the capsular interface will be filled with the filling medium outside of the eye, and sold pre-filled, as a complete intraocular lens, to the ophthalmologist. In this case, the entire lens will be compressed and inserted into the eye using an inserter device.
There is further provided an IOL for assisting the accommodative function of an eye having a thin flexible shell and a flexible, optically clear filling material. When the ciliary muscles of the eye contract during accommodation, the flexible lens will change shape such that the power of the lens will increase and allow the patient to focus at near. Once the muscles of accommodation relax, the lens will resume its baseline shape, allowing the patient to see at distance.
The IOL described herein is advantageous because compared to other devices, it utilizes natural accommodation to vary precisely the optical power of the eye without damaging the tissue thereof, or the circulating aqueous materials. The IOL can be soft and flexible to ensure the IOL-eye system re-establishes the accommodative mechanism so that the optical system of the patient can respond to changes in spatial images and illumination, permitting the lens to be installed by a simple procedure that can be quickly performed. In addition, the IOL localizes in the natural capsule so as to minimize de-centering and accommodation loss; providing functional performance similar to a natural eye; and allowing volumetric accommodation so that the ciliary muscle can control accommodation of the IOL. As a result, a greater variety of patients with lens disease can be provided with natural, responsive acuity, under a greater variety of circumstances, including but not limited to, enhanced capacity for accommodation, reduced glare, and permanent functionality because it utilizes a novel system of polymeric capsule and filling material to enhance the optical performance of the eye and establish normal visual experience.
These and other features of the systems and methods of the subject invention will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
Aspects of the disclosure will be described by reference to the following drawings, in which like numerals refer to like elements, and in which:
In the drawings, like reference numerals have been used throughout to designate identical elements. Preferred devices and methods will now be described in detail, with reference to
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The intraocular lenses developed must be created in a variety of predetermined powers. The power of a lens is a measurement of the lens' ability to bend light. The power of a lens is determined by the shape of the lens, the refractive index of the lens material, and the flexibility of the material. One novel approach to providing IOLs in a variety of dioptric powers is to create a standard capsular interface with one shape and one power, and to vary the refractive index of the filling material such that this variable allows for the creation of IOLs in a broad range of dioptric powers.
An alternative approach would be to also vary the materials of the capsular interface. In this embodiment, the capsular interface material would be selected according to the pre-measured strength of the patient's ciliary muscles. The muscles of accommodation, like all muscles in the body, vary in strength depending on the patient. Optical coherence tomography (OCT), a noninvasive imaging test that displays detailed cross sections of the retina, can also be used to image the ciliary muscles. Direct in vivo visualization of the ciliary muscles during accommodation has been performed using combined and synchronized two spectral domain OCT (SD-OCT). This could be one of the methods surgeons use to determine pre-operatively the strength of the patients' ciliary muscle. There are other methods for imaging the ciliary muscles such as ultrasound biomicroscopy and A-scan ultrasounds. It could be useful to take pre-operative measurements of the ciliary muscles. For patients with weaker ciliary muscles, the surgeons could select a more flexible intraocular lens.
Another preoperative measurement that could be useful for this adaptive IOL is a measurement of the exact shape and size of the natural lens of a patient. These measurements can be analyzed using tools such as high-resolution ocular coherence tomography and high frequency ultrasound biomicroscopy. This information can guide the choice of sizes of IOLs, so that surgeons can choose from a range of sizes. In addition, standard pre-operative measurements in use today measure necessary variables such as the axial length (AL) of the eye, the corneal power (K), and the shape of the cornea. Once these variables are analyzed, a customized intraocular lens can be created.
Corneal astigmatism is an imperfection in the curvature of the cornea. Toric IOLs have different powers along different meridians to correct for symmetrical cylinder error (astigmatism). In order for the Toric IOLs to function properly, they must be aligned and fixed in the capsular bag such that the axis of the IOL is aligned with the axis of the cylindrical error. Any post-surgical rotation of the lens degrades correction and can even introduce additional cylindrical error. The intra-capsular optic described herein has no risk of post-surgical rotation because it will fill the capsular bag and not be able to rotate postoperatively. Toric IOLs have different powers along different meridians in order to correct for cylindrical errors of the cornea. Different powers can be built along different meridians of the polymeric capsular interface. Alternatively, different powers can be built into the injectable filling material of the intra-capsular optic through slight alterations in the shape and composition of the material.
Currently, Toric IOLs can only correct “regular” astigmatism that is defined as a symmetrical steepening along a specific axis and bisecting in the center of the cornea in a bowtie configuration. The device can also be used to correct irregular astigmatism by altering the polymeric shell and filling material, respectively. Since the polymeric shell can be molded to a specific shape, the shell can mimic the irregularity of the cornea and be created to neutralize the irregularity and result in a symmetrical configuration.
Corneas have lower order aberrations (e.g. sphere and cylinder) that are corrected with glasses or contact lenses. However, corneas also have higher order aberrations (e.g. coma, trefoil) which affect vision. Newer diagnostic modalities have been created to evaluate for higher order aberrations. These higher order aberrations are diagnosed and treated during corneal laser refractive surgery. The device can also be used to correct higher order aberrations with the polymeric shell and filling material, respectively. It is contemplated that the configuration of the polymeric shell when filled with the filling material may define a shape selected to correct for “regular” or “irregular” astigmatism or higher order aberrations.
Indeed, it is further contemplated that that imaging and diagnostic tools including but not limited to corneal topography, tomography, and wavefront analyses may be used to understand such aberrations and to create a custom shaped polymeric shell based on the patient's particular needs. In one embodiment, such tools could be used to create a computer model of the ideal shape of an accommodative IOL, and the design of the polymeric shell could be selected based on such a model. With the polymeric shell custom made to fit the patient's particular circumstances, the shell could be pre-filled and provided for surgery as a custom-made implant or could be filled in-situ during surgery.
One method for creating a customized IOL is additive manufacturing (three-dimensional printing). The new artificial accommodative lens would replace the previous natural lens but due to the customized additive manufacturing, the artificial lens would form fit into the natural capsular bag.
During accommodation in a young, healthy lens, the majority of the increase in lens thickness is due to a forward movement of the anterior lens surface. In other words, the change in curvature of the anterior lens surface is more than the change in curvature of the posterior lens surface. As a biomimetic lens, the physiologically adaptive lens described herein might be most effective if its anterior lens surface had more of an increase in curvature than its posterior surface, just like a young human lens. In order to achieve this goal, the material selected for the anterior half of the lens would be more flexible than the material selected for the posterior portion of the lens.
A refracting telescope (e.g. Galilean telescope) uses a convergent objective lens and a divergent eye piece resulting in a non-inverted, upright magnified image. The device can be used as a refracting telescope to magnify the image. This is useful for patients who suffer from eye diseases such as age-related macular degeneration. In macular diseases, the patient loses the central visual field. By magnifying the image, the patient can see around the central scotoma and focus the light rays onto the remaining healthy portions of the macula to create a visual image. If the intra-capsular optic has an anterior portion of the polymeric shell with a certain power and the injectable filling material or posterior portion of the polymeric shell with a different power, the intraocular lens could act as a Galilean telescope and provide higher magnification for patients with diseases of the macula and retina. Such diseases include age-related macular degeneration, genetic macular disease, ocular albinism, and hereditary retinal degenerative diseases.
Posterior capsular opacification (PCO) occurs after cataract surgery due to the migration, proliferation and differentiation of lens epithelial cells and other potential causes of posterior capsular opacification (PCO). Studies have shown that pressure exerted on the capsular bag reduces epithelial cell proliferation or migration at the area of contact (the cause of PCO). It follows that PCO should not develop in eyes implanted with the above described optic. However, when PCO does form, the only method currently in use to remove the opacification from the posterior capsule is to perform post-operative YAG-laser capsulotomies. The laser's destruction of the posterior capsule may hinder the accommodative ability of the IOL in the early postoperative period until the capsular bag adheres to the IOL. This adherence can start as early as a week. Therefore, it is beneficial if PCO does not form quickly in eyes with accommodative IOLs. Experimental methods for preventing PCO formation include the use of antimetabolite, anti-inflammatory agents, hypo-osmolar drugs or immunological agents to prevent migration, proliferation and differentiation of lens epithelial cells and other potential causes of posterior capsular opacification (PCO). Coating the equatorial and posterior surfaces of the capsular interface with these agents in order to prevent PCO formation. These agents would also prevent fibrosis of the capsular bag which could theoretically impair the change in shape of the IOL.
It is the standard of care to administer certain post-cataract surgery medications. Currently, the medications administered are antibiotics, corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs). The antibiotics are to prevent an infection such as endophthalmitis, a rare but devastating complication. The corticosteroids and NSAIDs are used to decrease post-operative inflammation. The specific types of medications and protocols might change in the future. The polymeric capsule can be coated with post-cataract surgery medications so that patients will not be burdened with using eye drops post-operatively.
Coating the surfaces of the capsular interface with extended-release ocular medications such as anti-VEGF drugs for the treatment of wet Age-Related Macular Degeneration. VEGF refers to vascular endothelial growth factor, a signal protein that stimulates the formation of blood vessels. When overexpressed, VEGF can cause vascular disease in the retina and in other parts of the body. In patients with “wet” Age-related Macular Degeneration (AMD), VEGF promotes the growth of new, weak blood vessels behind the retina; those vessels leak blood, lipids and serum into the retinal layer and cause scarring in the retina and the death of macular cells. Anti-VEGF medications such as bevacizumab, aflibercept, ranibizumab and pegaptanib can inhibit VEGF and prevent the growth of leaky blood vessels. Currently, intravitreal injections of these VEGF-drugs are necessary. If we determine that the eye's capsule is permeable to these medications, we could coat the posterior surface of the IOL with slow-release anti-VEGF medication. Alternatively, we could put the medication in the filling material of the lens and allow the polymeric capsule to be permeable to the medication so that it could enter the vitreous.
Similarly, the surfaces of the capsular interface could be coated with extended-release ocular medications such as glaucoma medications for the long-term treatment of elevated intraocular pressure. Alternatively, the filling material could contain the medication and the polymeric capsule could be permeable to the medication so that it could enter the anterior chamber. Glaucoma, the second leading cause of blindness, is a complex disease in which damage to the optic nerve leads to progressive and irreversible vision loss. The loss of vision can be prevented with proper treatment of the increased intraocular pressure. In order to prevent vision loss, an intraocular pressure sensor could be incorporated into the capsular interface to monitor the intraocular pressure in patients with glaucoma.
Another way the lens could be used to prevent or treat ocular diseases is that the surfaces of the capsular interface could be coated with extended-release ocular medications for the treatment of other ocular disorders such as infections, inflammations, trauma, or drusen in the retina.
Adaptation of lenses for use in patients with color vision deficiency (CVD). CVD, also known as color blindness, affects approximately 8% of men and 0.5% of women worldwide. Thus, about 4.5% of the world's population is color blind. There are three types of cone photoreceptor cells that detect color: red, green and blue. The input from these cone cells allow our brain to perceive color. CVD occurs when one or more of the color cone cells are not working, absent, or detect a different color than normal. In the most common form of color blindness, people have a reduced sensitivity to green and red light. A filter or dye can be incorporated into the intraocular lens such that certain wavelengths of light are absorbed. For example, a dye can be used to block the band between the red and green wavelengths which is perceived simultaneously by both red and green cones in people with color vision deficiency. The removal of this band would inhibit the simultaneous triggering of the cones, thereby improving the distinction between the two cones' signals. EnChroma eyeglasses, for example, increase contrast between the red and green color signals by filtering out wavelengths of light at the point where excessive overlap of color sensitivity occurs.
The visible light region is normally defined as 400-700 nanometers (nm). The infrared light has longer wavelengths than those of visible light. The lens would allow the eye's sensitivity to extend into the infrared region using image enhancement technology. In this way, the lens would collect all of the available light, including infrared light, and amplify it. We could coat the lens with nanocrystals to shift the photon into the visible spectrum.
Measuring devices on the lens could be used for diagnostic purposes. Currently, patients only know of problems such as leaky vessels behind the retina when they perceive visual impairment or when they have a retina exam. If we had devices on the intraocular lens that could monitor the presence and quantity of red blood cells in the vitreous or the amount of Vascular Endothelial Growth Factor (VEGF) in the eye, we could prevent damage to the eye or diagnose problems just as they are beginning. Measuring devices could also monitor the presence and quantity of white blood cells in patients with chronic disorders such as uveitis. Patients would then know when their uveitis is flaring earlier than they typically do.
Monitors on the lens could also be used to measure aqueous humor glucose levels for diagnostic purposes for patients with diabetes. The anterior surface of the lens would be in close contact with the aqueous humor of the anterior chamber because the anterior capsulotomy will have left an opening in the eye's capsule. Aqueous humor glucose levels might be substituted for blood glucose levels for glucose level monitoring in patients with diabetes. In fact, the aqueous humor has been shown to contain glucose levels closely correlated to those of the blood.
Devices on the intraocular lens could monitor the presence and quantity of red blood cells in the vitreous or the amount of Vascular Endothelial Growth Factor (VEGF) in patients such as those with diabetic retinopathy, wet AMD or proliferative sickle-cell retinopathy. Measuring devices could also monitor the presence and quantity of white blood cells in patients with disorders such as infectious uveitis or uveitis due to autoimmune disorders. The presence of these cells would alert patients of the need for urgent treatment.
The outer layers of the retina, where photoreceptors reside, are gradually lost in retinal dystrophies such as retinitis pigmentosa (RP). While the photoreceptors are not available to trigger the phototransduction cascade to generate neuronal signals, restoration of vision may be achieved by creating retinal prostheses that receive and process incoming light and transmit the information in the form of electrical impulses to the remaining retinal ganglion cells (RGCs) within the inner layers. The axonal processes from RGCs form the optic nerve and transit these light-evoked neuronal signals directly to the visual cortex of the brain. While most retinal prostheses are placed on the retina, a prosthetic device could work as long as it delivers electrical impulses to RGCs. Solar cells use photovoltaic (PV) modules to convert light energy (photons) into electricity. PV modules could be inserted into the lens to work as retinal prosthetic devices. Alternatively, the filling material of the lens could convert light energy into electrical energy. In this way, the lens could transmit electrical impulses to the retina and act as a retinal prosthesis.
Many patients depend on peripheral vision because of damage to the fovea and subsequent reduced central vision, such as patients with dry AMD. If the focal point of the lens could be a ring around the fovea, rather than the fovea itself, patients with reduced central vision might have improved peripheral vision.
In patients with ocular albinism, a genetic condition in which the eyes lack melanin pigment, reduced visual acuity and sensitivity to bright light are two major problems. For patients with ocular albinism or with light sensitivity due to other factors, our lens could help them a great deal if it was coated with photochromic coatings that would allow the lens to transition to a darker shade, acting like permanent transition lenses. The lens could be coated with naphthopyrans that change their molecular structure reversibly when ultraviolet (UV) light strikes them. The absorption spectrum of naphthopyrans causes them to darken when UV light hits them. These would be possible compounds that could be used to coat the lens so that it reversibly could transition to a darker shade in response to UV light. Almost 90% of the risk of photo-oxidative damage to the retina from fluorescent lamps is due to 400-480 nm wavelengths of light. In addition, lenses that block blue light with wavelengths less than 450 nm (blue-violet light) increase contrast sensitivity. Computer glasses sometimes have yellow-tinted lenses to increase the comfort of people viewing digital devices. This lens could have coatings that partially absorb blue light within the wavelength range 400-480 nm.
The methods and system present disclosure, as described above and shown in the drawings, provide for a physiologically adaptive intra-capsular optic with superior properties. While the apparatus and methods of the subject disclosure have been showing and described with reference to embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and score of the subject disclosure.
This application claims priority to U.S. Provisional Application Ser. No. 62/904,389, filed Sep. 23, 2019, the entire contents of which incorporated by reference herein in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US20/52316 | 9/23/2020 | WO |
Number | Date | Country | |
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62904389 | Sep 2019 | US |