HK1140726B - Tinted contact lenses having a depth effect - Google Patents

Description

Tinted contact lenses with depth effect

Technical Field

The present invention relates to tinted contact lenses. In particular, the present invention provides contact lenses (also known as "contact lenses") that can alter or enhance the natural color of the lens wearer's iris.

Background

It is known to use tinted or colored contact lenses to alter or enhance the natural color of the iris. In the preparation of conventional tinted lenses, it is known to use either or both translucent or opaque colors in one or more color layers to achieve a tinted iris that creates a natural appearance. Each color layer is typically applied as a single layer. This provides a color change only when multiple color layers or dots are used where a semi-transparent color layer overlaps another color layer. However, the natural iris is composed of a large number of different colors and color combinations intermixed to produce color variations. The relatively few colors and color layers that can be used to make tinted contact lenses limits the designer's ability to make natural looking irises.

In addition, conventional tinted lenses have the disadvantage that they lack the three-dimensional appearance of the natural iris. This results in a flat, unnatural appearance when the lens is worn.

Drawings

FIG. 1 is a cross-sectional view of a mold half used to prepare the lenses of the invention.

FIG. 2 is a cross-sectional view of a lens of the invention.

Detailed description of the invention and preferred embodiments

The present invention provides tinted contact lenses that enhance or alter the color of the lens wearer's iris and methods for their preparation. The lenses of the invention are prepared to give the lens pattern a three-dimensional appearance when the lens is worn, to give the pattern a depth, and to give the pattern a more natural appearance. The present invention has found that this can be achieved in tinted lenses by using alternating clear and color layers. The lenses of the invention may function as cosmetic lenses to enhance the iris or change the color of the iris of an individual, or both.

In one embodiment, the invention provides a contact lens having at least one surface comprising at least two clear layers alternating with at least one color layer. In an alternative embodiment, the invention provides a contact lens having at least one surface comprising at least two color layers alternating with at least one clear layer.

By "transparent layer" is meant a layer of material that is substantially free of any dyes or pigments.

By "colored layer" is meant a layer comprising opaque color regions, translucent color regions, or a combination thereof. By "translucent" is meant a color such that the average transmission (% T) of light in the range of 380 to 780nm is greater than or equal to about 60% T, preferably greater than or equal to about 65% T. By "opaque" is meant a color such that the average transmission (% T) of light in the range of 380 to 780nm is from 0 to about 55% T, preferably from 7 to about 50% T.

The clear and color layers can be applied to the back or eye side, surface or front, or object side surfaces of the lens, or combinations thereof.

Preferably all layers are on the front surface of the lens. To achieve the desired depth effect, the clear and color layers must be applied or printed in alternating sequence. The clear and color layers can be applied directly to the contact lens surface or, preferably, the clear and color layers are applied to the molding surface of a lens mold half, the mold half is then filled with lens material, the complementary mold half is used to complete the mold assembly, and the mold assembly is exposed to conditions suitable to cure the lens material used.

For example and referring to fig. 1, a cross-sectional view of a front curve mold half 10 for a contact lens is shown. The clear layer 12 is first printed onto the concave surface of the mold halves, followed by the color layer 13. Clear layer 14 is printed onto color layer 13, followed by printing color layer 15 onto clear layer 14. In fig. 2, a lens 20 of the present invention is shown having a concave surface 22 and a convex surface 27. On convex surface 27 are shown color layers 23 and 25 alternating with clear layers 24 and 26.

The thickness of each layer will depend on the material or materials used to form each layer, the method used to print the layer, the pattern of the printing cliche used, and the design. The first clear layer preferably has a thickness of between about 5 to about 15 μm, and each color layer preferably has a thickness of between about 5 to about 15 μm, although a thickness of up to 50 μm is possible. It is most preferred that each color layer be as thin as possible. In addition to the first transparent layer, each subsequent transparent layer is preferably thicker than the first transparent layer and has a thickness of from about 5 to about 150 μm, more preferably from about 5 to about 50 μm. The number of clear and color layers used will depend on the thickness of each layer and the degree of depth effect desired. Preferably 2 clear layers and 2 color layers are used.

The entirety of each color layer may comprise an opaque color, a translucent color, or a combination thereof. Alternatively, the color layer may have a colorless central region, preferably substantially circular, surrounded by a colored region comprising an opaque color, a translucent color, or a combination thereof. It is preferred to have a clear central zone on the lens such that when the lens is on-eye, the clear zone partially or completely covers the lens wearer's pupil and the colored zone partially or completely covers one or both of the lens wearer's iris and corneal ring. Preferably, the clear layer corresponds to the size and shape of the adjacent color layer or layers. Each adjacent layer, whether a color layer or a clear layer, may cover all or only a portion of the surface, layer or layers adjacent thereto. For example, the layer may be printed only on the optic zone or lens portion of the optic surface. The clear and color layers are preferably disposed on the lens such that they each cover one or both of the lens wearer's iris and corneal ring when the lens is on-eye.

When the lenses of the invention are worn, the combination of the colored areas of all colored layers used covers greater than about 85%, preferably equal to or greater than about 90%, of the individual iris area and covers about 0 to 100% of the corneal ring. This has the advantage that the iris color can be changed or enhanced without blocking the natural iris structure or affecting the visual function, and at the same time provide a depth appearance in the pattern. Furthermore, even the darkest colors on the iris can be changed using the color layer of the present invention.

Each of the clear and color layers used in the lenses of the invention can be applied to or printed on the lens surface or lens forming surface of the mold halves by any convenient method. In a preferred method, a thermoplastic optical mold is used that is made of any suitable material including, but not limited to, cyclic polyolefins and polyolefins such as polypropylene or polystyrene resin. The colored and transparent layers are alternately deposited on desired portions of the molding surface of the mold. By "molding surface" is meant the surface of the mold or mold half used to form the lens surface. Deposition is preferably performed so that the outermost color layer on the lens surface is a clear layer. The deposition is preferably performed by pad printing as follows.

The metal plate made of steel and more preferably stainless steel is preferably covered with a photoresist material that is capable of becoming water insoluble when cured. The pattern of the color layer is selected or designed and then reduced to the desired size using any of a variety of techniques, such as photographic techniques, placed on the metal plate, and the photoresist cured.

After patterning, the metal plate is washed with an aqueous solution and the resulting image is etched into the plate to a suitable depth, for example about 20 microns. A colorant comprising a binding polymer, a solvent, and a pigment or dye is then deposited on the pattern such that the colorant fills the depressions. A silicon pad having a geometry suitable for printing on a surface and varying in hardness, typically from about 1 to about 10, is pressed against the image on the plate to remove the colorant, and the colorant is then allowed to slowly dry by solvent evaporation. The shim is then pressed against the molding surface of the optical mold. The mold is degassed for up to 12 hours to remove excess solvent and oxygen before filling the mold with lens material. The complementary mold halves are then used to complete the mold assembly and the mold assembly is exposed to conditions suitable for curing the lens material used. Such conditions are well known in the art and will depend on the lens material selected. When curing is complete and the lens is demolded, it is allowed to equilibrate in a buffered saline solution.

Each transparent layer may be a pre-polymer layer, a monomer layer, or a polymer layer. Preferably each clear layer is a pre-polymer layer that covers at least a portion of an adjacent color layer, and preferably covers the entire color layer. The prepolymer, monomer or polymer selected may be any material capable of dispersing the pigment and any opacifying agent used.

The color selected for use in each color layer will be determined by the natural color of the lens wearer's iris and the color of which the natural color is intended to be changed or the degree to which the natural color is intended to be enhanced. Thus, the color can be any color including, but not limited to, any of a variety of hues and chromas of white, black, blue, green, gray, brown, yellow, red, or combinations thereof.

The present invention can be used to provide colored hard or soft contact lenses made of any known lens-forming material or materials suitable for making such lenses. Preferably, the lenses of the invention are soft contact lenses and the material selected to form the lenses of the invention can be any material suitable for making soft contact lenses. Suitable preferred materials for forming soft contact lenses using the methods of the present invention include, but are not limited to, silicone elastomers, silicone-containing macromers including, but not limited to, those disclosed in U.S. Pat. Nos. 5,371,147, 5,314,960, and 5,057,578 incorporated in their entireties herein by reference, hydrogels, silicone-containing hydrogels, and the like, and combinations thereof. More preferably, the surface is a siloxane or contains siloxane functionality, including but not limited to polydimethylsiloxane macromers, methacryloxypropyl polyalkyl siloxanes, and mixtures thereof, silicone hydrogels, or such hydrogels: made from monomers containing hydroxyl groups, carboxyl groups, or both, or from silicone-containing polymers such as silicones, hydrogels, silicone hydrogels, and combinations thereof. Materials for making soft contact lenses are well known and commercially available. Preferably, the material is argofukang, etafilkang, gentamicin, or linnfikang.

The color zone may be made of any organic or inorganic pigment suitable for use in contact lenses or a combination of such pigments. Opacity can be controlled by varying the concentrations of the pigment and titanium dioxide used, with higher amounts yielding greater opacity. Exemplary organic pigments include, but are not limited to, phthalocyanine blue, phthalocyanine green, carbazole violet, vat orange #1, and the like, and combinations thereof. Examples of useful inorganic pigments include, but are not limited to, black iron oxide, brown iron oxide, yellow iron oxide, red iron oxide, titanium dioxide, and the like, and combinations thereof. In addition to these pigments, soluble and insoluble dyes may be used, including but not limited to dichlorotriazine and vinyl sulfone type dyes. Useful dyes and pigments are commercially available.

The selected dye or pigment can be mixed with one or more prepolymers or binding polymers and a solvent to form the colorant used to prepare the translucent and opaque color layers used in the lenses of the invention. The prepolymer may be any polymer capable of dispersing the pigment and any opacifying agent used. Other additives useful in contact lens colorants may also be used. Binding polymers, solvents and other additives useful in the color layers of the present invention are known and are commercially available or methods of making them are known.

The color zones of one or more color layers may be uniform or have a radially gradient appearance, meaning that the color density varies, or the arrangement of size, density and tint shape within the zone varies, creating a radially gradient effect. The uniform color region may comprise a transparent shape including, but not limited to, a circle, an ellipse, a triangle, a line, a stripe, a feather-like shape, and the like, and combinations thereof. Alternatively, the color region may be comprised of opaque colored shapes, such as those listed. The number, size and shape used will be determined by the desired effect to be achieved by the lens. The color zone may also contain a pattern of many intermittent opaque shapes to help provide additional depth to the resulting image.

Claims (9)

1. Contact lens comprising at least two clear layers alternating with at least one color layer, wherein each of said clear layers has a thickness of 5 to 150 μm and each color layer has a thickness of 5 to 15 μm, the combination of color areas of all color layers used covering more than 85% of the individual iris area and covering 0 to 100% of the corneal ring when the lens is worn on the eye, wherein one of said clear layers is thinner than each of the other said clear layers.

2. Contact lens comprising at least two color layers alternating with at least one clear layer, wherein each of said clear layers has a thickness of 5 to 150 μm and each color layer has a thickness of 5 to 15 μm, the combination of color areas of all color layers used covering more than 85% of the individual iris area and covering 0 to 100% of the corneal ring when the lens is worn on the eye, wherein one of said clear layers is thinner than each of the other said clear layers.

3. The contact lens of claim 1, wherein each of the colored layers comprises a clear colorless central area and a colored area.

4. The contact lens of claim 2, wherein each of the colored layers comprises a clear colorless central area and a colored area.

5. The contact lens of claim 3, wherein the central zone is circular and the colored zone is an annular zone surrounding the central zone.

6. The contact lens of claim 4, wherein the central zone is circular and the colored zone is an annular zone surrounding the central zone.

7. Contact lens comprising at least two clear layers alternating with at least two color layers, wherein each of said clear layers has a thickness of 5 to 150 μm and each color layer has a thickness of 5 to 50 μm, wherein one of said clear layers is thinner than each of the other said clear layers.

8. A method of providing a tinted contact lens comprising the steps of: providing at least two clear layers alternating with at least one color layer in the lens, wherein each of the clear layers has a thickness of 5 to 150 μm and each color layer has a thickness of 5 to 15 μm, the combination of color areas of all color layers used covering more than 85% of the individual iris area and covering 0 to 100% of the corneal ring when the lens is worn on the eye, wherein one of the clear layers is thinner than each of the other clear layers.

9. A method of providing a tinted contact lens comprising the steps of: providing at least two clear layers alternating with at least one color layer on the lens surface, wherein each of the clear layers has a thickness of 5 to 150 μm and each color layer has a thickness of 5 to 15 μm, the combination of color areas of all color layers used covering greater than 85% of the individual iris area and covering 0 to 100% of the corneal ring when the lens is worn on the eye, wherein one of the clear layers is thinner than each of the other clear layers.