Contact lens with PVA film

Abstract

A film having a hydrophobic, water-insoluble dye embedded in polyvinyl alcohol (PVA) is disclosed. The dye is uniformly distributed throughout the membrane, and the membrane is substantially free of organic solvents. The membrane can be attached to the center of the contact lens. The contact lens can be used for correcting or improving the color vision of people with color vision deficiency.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 458,028, filed April 7, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention generally relates to colored contact lenses. Background Technology

[0004] Coloring contact lenses with dyes plays a vital role in the contact lens industry for various reasons, including coloring to facilitate identification of contact lenses in saline solutions (so-called visible coloring), the use of colored contact lenses for cosmetic purposes, the management of frequent migraines, and the production of photochromic contact lenses. Various coloring methods disperse the dye within the contact lens material. However, dispersing the dye within the contact lens material presents a practical problem for soft contact lenses with high water content, potentially leading to leaching into the eye. Another issue is that the effective dye is dispersed throughout the contact lens, rather than in areas where effective dyeing is particularly needed. Summary of the Invention

[0005] This specification discloses a contact lens having a lens body and a film coated on a central portion of the lens body. The film can be attached to the convex surface of the contact lens body. In some examples, the diameter of the film is between 4 mm and 7 mm, and the diameter of the lens body is greater than 9 mm. The film coating the central portion of the contact lens body is made of polyvinyl alcohol (PVA), with water-insoluble dyes (or hydrophobic dyes) embedded within the PVA. The film is substantially free of organic solvents. The water-insoluble dyes (or hydrophobic dyes) are uniformly distributed throughout the film. The lens body itself does not contain any water-insoluble dyes.

[0006] Water-insoluble (or hydrophobic) dyes are embedded in PVA, preventing migration of the dye from the membrane after immersion in a salt solution for 30 days. Two or more dyes can be embedded in the PVA membrane. The dyes can be narrow-band dyes. The dyes can be metal complex dyes.

[0007] The dyes (or dyes) in the film make it an optical filter with an absorption spectrum. One or more dyes in the film may be narrowband dyes with peak absorption in the range of 560 nm to 620 nm. The film may have an absorption spectrum with absorption peaks in the range of 560 to 620 nm, wherein the optical density of the peak absorption is greater than 1. Films with these optical qualities can be used in conjunction with contact lenses to correct or improve the wearer's color vision in cases where the wearer has a color vision deficiency.

[0008] This specification discloses a PVA film having an embedded water-insoluble dye (or hydrophobic dye) and a method for preparing it. The method begins by providing an organic solvent that does not form an azeotropic mixture with water. For example, the organic solvent may be methanol or acetone. The water-insoluble dye (or hydrophobic dye) is then dissolved in the organic solvent to form a dye solution. The dye solution is then mixed with an aqueous solution of polyvinyl alcohol (PVA) to form a PVA dye solution. Subsequently, substantially all of the organic solvent is removed from the PVA dye solution to form an aqueous PVA dye solution.

[0009] In some cases, substantially removing all organic solvent involves heating the PVA dye solution until the PVA dye is in solid form. This is followed by flowing dry nitrogen or argon gas to substantially remove all remaining free water. This solid form of PVA dye can be stored and rehydrated as needed to form an aqueous PVA dye solution. In some cases, the viscosity of the aqueous PVA dye solution is greater than 30 mPa·s.

[0010] A PVA dye aqueous solution can be made into a film by coating a substrate with the PVA dye aqueous solution and then curing it. The PVA dye aqueous solution can also be printed or coated onto the central portion of the surface of a contact lens. After printing or coating, the PVA dye aqueous solution on the contact lens cures to form a PVA dye film on the surface of the contact lens body. The contact lens body does not contain any water-insoluble dyes (or hydrophobic dyes). Attached Figure Description

[0011] The figures described below depict various aspects of the systems and methods disclosed herein. Each figure depicts an embodiment of a specific aspect of the disclosed systems and methods, and each figure is intended to conform to its possible embodiments. Furthermore, where possible, the following description refers to element symbols contained in the figures below, wherein features depicted in multiple figures are indicated by consistent element symbols.

[0012] Figure 1 illustrates a contact lens. Figure 1A It is a cross-sectional view, and Figure 1B It is a plan view. Detailed Implementation

[0013] The following detailed description should be read with reference to the accompanying drawings, in which the same element symbols in different figures generally refer to the same element. The drawings (which are not necessarily drawn to scale) depict alternative embodiments and are not intended to limit the scope of the invention. The detailed description illustrates the principles of the invention by way of example and not limitation.

[0014] Figure 1A and 1B A contact lens 10 is shown for correcting color vision deficiencies. Figure 1A This is a cross-sectional view of contact lens 10, and Figure 1BThis is a plan view of contact lens 10. The lens body 20 of contact lens 10 can be a hard lens, a soft lens, an extension lens, or any other type of contact lens. The lens body 20 is typically defined by a concave inner surface or concave base surface 21 and a convex outer surface 22. Typically, the diameter of the lens body 20 is between 13 mm and 15 mm. Preferably, the diameter of the lens body is greater than about 9 mm. Typically, the central area of ​​the contact lens covers the pupillary area of ​​the wearer's eye. The lens body is preferably formed of a generally transparent, biocompatible lens material. For example, the lens body can be formed of a polymerized hydroxyethyl methacrylate (HEMA)-based lens material, such as Methafilcon A, or other biocompatible transparent materials. The lens body may or may not be tinted. The lens body may be configured to provide a certain degree of optical vision correction or may not be configured in this way, i.e., the lens body may or may not provide a prescription power.

[0015] The contact lens 10 also includes a polyvinyl alcohol (PVA) film 30 embedded with a narrow band dye. The film 30 coats the central area of ​​the contact lens, i.e., the area covering the pupil of the wearer's eye but preferably not extending beyond the iris. In some embodiments, the film has a diameter of approximately 6 mm, covering a central portion of the contact lens body of 13 mm to 15 mm. The diameter of the film 30 may be in the range of 4 to 7 mm. Figure 1A A film 30 is shown coating the convex outer surface 22 of a contact lens. Film 30 may also be coated on the convex surface 22 of a contact lens. The thickness of film 30 ranges from 5 to 25 μm, preferably about 15 μm. The molecular weight (MW) of PVA in film 30 can be in the range of 22,000 to 220,000, and the degree of hydrolysis (DH) is 85% to 89%.

[0016] Membrane 30 contains one or more dyes. These dyes are hydrophobic organic dyes that are insoluble in water. The dyes may be metal complex dyes. The dyes may be narrowband dyes. Narrowband dyes are dyes with absorption peaks whose full width at half maximum (FWHM) is at most 40 nanometers. The one or more dyes in membrane 30 create an optical filter that corrects the wearer's color vision. Although membrane 30 contains one or more hydrophobic, water-insoluble dyes, the contact lens body 20 does not contain any hydrophobic, water-insoluble dyes. The concentration of the dyes in membrane 30 ranges from 100 to 5000 ppm. The one or more hydrophobic, water-insoluble dyes are uniformly distributed throughout the membrane, meaning the dye concentration is the same throughout the membrane.

[0017] It is better to have the dye uniformly distributed throughout the membrane than to concentrate it on the membrane surface. When dye is introduced into the membrane by diffusion, high concentrations of dye remain near the membrane surface, while relatively less dye remains in the membrane center, because diffusion depends on the concentration gradient. This type of concentration profile is unfavorable compared to a membrane with uniform dye distribution, because dye on the membrane surface can diffuse out of the membrane more easily. Furthermore, dye diffusion out of the membrane will alter the optical properties of the membrane, which is undesirable.

[0018] The dye is stably embedded in membrane 30 without any organic solvents, such as acetone, methanol, etc. Contact lenses with a PVA membrane containing a water-insoluble narrow-band dye can be immersed in phosphate-buffered saline (PBS) solution or other similar contact lens storage solutions (“salt solutions”) at room temperature for more than one month (30 days) without any visible leaching of the dye into the salt solution. Furthermore, contact lenses with a PVA membrane containing a water-insoluble narrow-band dye can be immersed in a salt solution maintained at 37°C for 14 days without any visible leaching of the dye into the salt solution. To demonstrate complete dye embedding within the PVA polymer, the PVA dye membrane can be dissolved in water at approximately 50°C, resulting in a solution with the color of the dye, and no dye precipitation in the solution due to complete dye embedding within the PVA polymer.

[0019] The method of embedding hydrophobic, water-insoluble dyes into hydrophilic polymers (such as PVA) relies on first dissolving the dye in an organic solvent (such as acetone or methanol) to produce a dye solution. This acetone or methanol dye solution is added to a dilute PVA solution at approximately 30 to 35°C to produce an optically transparent solution of the PVA dye aqueous solvent, meaning that neither the dye nor the PVA precipitates from the solution. An important requirement for preparing this optically transparent solution of PVA and dye is that both the dye solution and the PVA solution need to be dilute. Furthermore, the organic solvents acetone or methanol are particularly useful for producing the dye solution because neither solvent forms an azeotropic mixture with water. This allows for the removal of substantially all of the organic solvent from the dye solution. For example, substantially all of the acetone or methanol can be removed from the PVA dye aqueous solvent solution by heating at a low temperature, such as well as well below the boiling point of water. If the PVA dye aqueous solvent solution is dried on a substrate, the solvent is removed, leaving a thin PVA dye film. Because the film is made from the dye solution, the hydrophobic, water-insoluble dye is uniformly distributed throughout the PVA film.

[0020] To remove substantially all acetone or methanol, additional purification steps are required. Although acetone and methanol form a non-azeotropic mixture with water, they will form hydrogen bonds with water, making removal difficult. To remove substantially all acetone or methanol, water must be removed. In the first purification step, the PVA dye aqueous solvent solution is heated to approximately 65°C to remove acetone or methanol. This reduces the solvent / water ratio to a very low value. As acetone or methanol is removed, the water content will decrease proportionally (azeotropic). Reducing the water content to less than 100 ppm will reduce the acetone or methanol content to less than 1 ppm. This is possible because PVA is insoluble in acetone or methanol, and because the boiling points of both organic solvents are at or near 65°C, and their vapor pressures are 4 to 5 times that of water at 65°C. The first additional purification step dries the solution to form a solid by heating it to 70 to 75°C. This solid can be further decomposed to form a powder. In a second, additional purification step, the solid is heated at 60 to 85°C in a flowing atmosphere of dry nitrogen or argon to entrain and remove substantially all remaining free water. The powdered form of the solid will release free water at a faster rate. The anhydrous solid can now be stored or rehydrated. These purification steps allow for the production of aqueous solutions of PVA with hydrophobic dyes in solution, without any detectable trace amounts of organic solvents used to form the dye solution.

[0021] Preferably, a PVA dye aqueous solution is printed onto the concave or convex surface of the contact lens body using a transfer printing technique. The viscosity of the PVA dye aqueous solution should be maintained within approximately 40 mPa·s to prevent uneven flow or drying of the solution, for example, a viscosity greater than 30 mPa·s. The target viscosity value can be achieved by removing sufficient water from the PVA dye aqueous solution before transfer. PVA is printed onto the contact lens body in its unhydrated (dried) "chip" form. After printing, the PVA dye aqueous solution is cured by passive drying (partially crosslinking PVA) or UV irradiation (if a photoinitiator is added to the solution to fully crosslink PVA). The curing of the PVA dye aqueous solution on the contact lens body forms the film 30 of the contact lens 10.

[0022] The peak wavelength of dye absorption needs to be determined experimentally. The spectral characteristics of the dye are affected by its embedding in the PVA film: specifically, the microwave (MW) and dh (DH) of the PVA polymer film influence the dye's maximum peak absorption and spectral linewidth. Understanding these spectral characteristics is necessary for optimizing filter design. The spectral characteristics of the dye were measured in PVA with different MWs and 98% high DH. It was observed that with PVA MW above 60,000 and DH exceeding 98%, the peak wavelength, intensity, and full width at half maximum (FWHM) remained stable.

[0023] One method for correcting or enhancing color vision in individuals with color vision deficiencies is to provide an optical filter that enhances the contrast between green and red hues. This filter can be manufactured using a narrowband dye with peak absorption in the range of 560 nm to 620 nm. Preferably, the optical density spectrum of the filter containing the narrowband dye has an optical density greater than 1 at the peak absorption wavelength of the narrowband dye. For example, if the optical density spectrum of a PVA dye film has a peak absorption in the range of 560 nm to 620 nm, and said peak absorption has an optical density greater than 1, then the PVA dye film can provide this optical filter.

[0024] Example 1.

[0025] The narrowband exciton dye ABS-574L was dissolved in methanol at a concentration of 0.12 g / L. 11.4 ml of the dye solution was added to 13 g of a 4% PVA solution with a degree of hydrolysis of 89% and a molecular weight distribution in the range of 20,000 to 200,000, and maintained at 30°C. This solution was stirred at 65°C for 1 hour. Thin films of the PVA dye solution were prepared and dried on glass slides. These films exhibited excellent optical quality, displaying maximum absorption at 576 nm in the recorded spectrum ranging from 400 to 700 nm, and could be used as optical filters.

[0026] Example 2.

[0027] Narrow-band exciton dye ABS-594 was dissolved in methanol at a concentration of 0.49 g / L. 10.5 ml of the dye solution was added to 8.0 g of 4% PVA solution with a degree of hydrolysis of 89% and a molecular weight distribution in the range of 20,000 to 200,000, and maintained at 30 °C. This solution was stirred at 65 °C for 1 hour. Thin films of the PVA dye solution were prepared and dried on glass slides. These films exhibited excellent optical quality, displaying maximum absorption at 599 nm in the recorded spectrum in the range of 400 to 700 nm, and could be used as optical filters.

[0028] Example 3.

[0029] Narrow-band exciton dye ABS-594 was dissolved in acetone at a concentration of 0.49 g / L. 10.5 ml of the dye solution was added to 8.0 g of 4% PVA solution with a degree of hydrolysis of 89% and a molecular weight distribution in the range of 20,000 to 200,000, and maintained at 30°C. This solution was stirred at 65°C for 1 hour. Thin films of the PVA dye solution were prepared on glass slides and allowed to dry. These films exhibited excellent optical quality, displaying maximum absorption at 599 nm in the recorded spectrum in the range of 400 to 700 nm, and could be used as optical filters.

[0030] Example 4.

[0031] An aqueous solution of ABS-594 PVA dye (from Example 2) was applied to the center of the contact lens body in a dry chip form. The lens was then dried in an oven at room temperature. After drying, the contact lens was immersed in a saline solution for over one month. After one month in the saline solution, no visible dye leached into the saline solution, and a thin layer of PVA dye remained adhered to the contact lens.

[0032] Example 5.

[0033] An aqueous solution of PVA dye from ABS-594 (from Example 2) was applied to the center of the contact lens body (Methafilcon A). The lens was then dried in an oven at room temperature. After drying, the contact lens was immersed in a salt solution maintained at 37°C for 14 days. No visible dye leached into the salt solution, and the thin layer of PVA dye remained stable and adhered to the center of the contact lens.

[0034] Example 6.

[0035] A thin film of an aqueous PVA dye solution of ABS-594 (from Example 2) was coated onto a glass slide and dried in an oven at room temperature. When this PVA dye film was immersed in water at 50°C, the PVA dye film dissolved in the water. The solution was transparent and had the color of the dye, indicating that the dye was still embedded in the PVA polymer. If the dye were not embedded in the polymer, the water-insoluble dye would precipitate from the solution, and the solution would be colorless.

[0036] Example 7.

[0037] An aqueous solution of ABS-594 PVA dye (from Example 2) was stirred at 65°C for 1 hour. The solution was then heated to 70-75°C until all water was removed and the PVA dye solidified. The solid PVA dye was then pulverized and heated to 70-75°C in flowing dry argon to remove all remaining water and any remaining trace amounts of methanol. This solid PVA dye was stored in water and rehydrated. The rehydrated PVA dye solution did not contain detectable trace amounts of methanol.

Claims

1. A contact lens comprising: The lens body includes a surface and a central portion, and the lens body does not contain water-insoluble dyes; and A film coated on the central portion of the surface of the lens body, the film comprising a water-insoluble dye embedded in polyvinyl alcohol (PVA), the water-insoluble dye being uniformly distributed throughout the film, the film being substantially free of organic solvents.

2. A contact lens comprising: A lens body comprising a surface and a central portion, wherein the lens body does not contain hydrophobic dyes; and A film coated on the central portion of the surface of the lens body, the film comprising a hydrophobic dye embedded in polyvinyl alcohol (PVA), the hydrophobic dye being uniformly distributed throughout the film, the film being substantially free of organic solvents.

3. The contact lens according to claim 1 or 2, wherein the dye is embedded in the PVA such that the dye does not migrate out of the membrane after 30 days in a salt solution.

4. The contact lens according to claim 1 or 2, wherein the surface is convex.

5. The contact lens according to claim 1 or 2, wherein the film comprises two or more water-insoluble dyes.

6. The contact lens according to claim 1 or 2, wherein the dye is a narrow-band dye.

7. The contact lens of claim 6, wherein the narrow-band dye has a peak absorption in the range of 560 nm to 620 nm.

8. The contact lens of claim 7, wherein the film is an optical filter having an absorption spectrum and an optical density greater than 1 at the wavelength of the peak absorption.

9. The contact lens according to claim 6, wherein the dye is a metal complex dye.

10. The contact lens according to claim 1 or 2, wherein the diameter of the membrane is between 4 mm and 7 mm, and the diameter of the lens body is greater than 9 mm.

11. A method for manufacturing a contact lens, comprising: Provide organic solvents that do not form azeotropic mixtures with water; The water-insoluble dye is dissolved in the organic solvent to form a dye solution; The dye solution is mixed with an aqueous solution of polyvinyl alcohol (PVA) to form a PVA dye solution; substantially all of the organic solvent is removed from the PVA dye solution to form an aqueous PVA dye solution; The PVA dye aqueous solution is printed onto the central portion of the surface of the contact lens; and The PVA dye aqueous solution is cured onto the contact lens to form a PVA dye film on the surface of the contact lens.

12. The method according to claim 11, wherein the organic solvent is methanol.

13. The method according to claim 11, wherein the organic solvent is acetone.

14. The method of claim 11, wherein the surface is a convex surface.

15. The method of claim 11, wherein dissolution comprises dissolving the second water-insoluble dye in methanol or acetone.

16. The method of claim 11, wherein the water-insoluble dye is a narrow-band dye.

17. The method of claim 16, wherein the water-insoluble dye is a metal complex dye.

18. The method of claim 11, wherein printing comprises printing the aqueous PVA dye onto the central portion of the contact lens having a diameter between 5 mm and 7 mm.

19. The method of claim 11, wherein prior to printing, water is removed from the PVA dye aqueous solution until the viscosity of the solution is greater than 30 mPa·s.

20. The method of claim 11, wherein the curing crosslinks the PVA in the PVA dye aqueous solution.

21. A membrane comprising: A hydrophobic, water-insoluble dye is embedded in polyvinyl alcohol (PVA), the dye is uniformly distributed throughout the membrane, and the membrane is generally free of organic solvents.

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