FUNCTIONAL CONTACT LENS AND METHOD FOR DYEING THE SAME

Abstract

A method for dyeing a functional contact lens includes steps of: providing a lens body; formulating a first solution, wherein the first solution is an ionic salt solution containing an alkali; placing the lens body in the first solution and reacting at 30 C. to 80 C.; formulating a second solution, wherein the second solution is an ionic salt solution containing at least one reactive dye; and placing the lens body in the second solution and reacting at 30 C. to 80 C.; wherein the at least one reactive dye reacts with the lens body to be fixed to a surface portion of the lens body. In order to achieve one or a portion or all of the above or other objects, the present invention further provides a functional contact lens including a lens body and a dye layer on a surface of the lens body and can be obtained by the aforementioned method.

Claims

1. A method for dyeing a functional contact lens, comprising steps of: providing a lens body; formulating a first solution, wherein the first solution is an ionic salt solution containing an alkali; placing the lens body in the first solution and reacting at 30 C. to 80 C.; formulating a second solution, wherein the second solution is an ionic salt solution containing at least one reactive dye; and placing the lens body in the second solution and reacting at 30 C. to 80 C.; wherein the at least one reactive dye reacts with the lens body to be fixed to a surface portion of the lens body.

2. The method for dyeing a functional contact lens according to claim 1, further comprising a step of: placing the lens body in the first solution and reacting at 30 C. to 80 C. for 10 to 60 minutes.

3. The method for dyeing a functional contact lens according to claim 1, further comprising a step of: placing the lens body in the second solution and reacting at 30 C. to 80 C. for 10 to 60 minutes.

4. The method for dyeing a functional contact lens according to claim 1, wherein the step of placing the lens body in the second solution and reacting at 30 C. to 80 C. further comprises a step of: forming a dye layer on the surface portion of the lens body.

5. The method for dyeing a functional contact lens according to claim 4, wherein a thickness of the dye layer is 0.5 um to 40 m.

6. The method for dyeing a functional contact lens according to claim 1, wherein a concentration of the alkali of the first solution is 0.01 wt % to 4 wt %, and a concentration of an ionic salt thereof is 0.01 wt % to 10 wt %.

7. The method for dyeing a functional contact lens according to claim 1, wherein a concentration of the that least one reactive dye of the second solution is 0.01 wt % to 5 wt %, and a concentration of an ionic salt thereof is 0.01 wt % to 10 wt %.

8. The method for dyeing a functional contact lens according to claim 1, wherein the first solution has an osmotic pressure of 300 to 800 mOsm/kg H.sub.2O.

9. The method for dyeing a functional contact lens according to claim 1, wherein the second solution has an osmotic pressure of 300 to 800 mOsm/kg H.sub.2O.

10. The method for dyeing a functional contact lens according to claim 1, wherein the reactive dye is selected from a group consisting of a black dye, a yellow dye, an orange dye, a blue dye, and a red dye or a combination thereof.

11. The method for dyeing a functional contact lens according to claim 6, wherein the first solution contains sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, boric acid, sodium tetraborate or a combination thereof, and the second solution contains sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, boric acid, sodium tetraborate or a combination thereof.

12. The method for dyeing a functional contact lens according to claim 7, wherein the first solution contains sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, boric acid, sodium tetraborate or a combination thereof, and the second solution contains sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, boric acid, sodium tetraborate or a combination thereof.

13. The method for dyeing a functional contact lens according to claim 1, wherein the lens body has a moisture content of 20% to 80%.

14. The method for dyeing a functional contact lens according to claim 1, wherein the lens body has an oxygen permeability range of 810.sup.11 to 18810.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg).

15. The method for dyeing a functional contact lens according to claim 1, further comprising a step of: placing the lens body in water for hydration.

16. The method for dyeing a functional contact lens according to claim 15, further comprising the step of: placing the lens body in a buffer and sterilizing in parallel.

17. A functional contact lens comprising a lens body and a dye layer disposed on a surface portion of the lens body, and the functional contact lens is manufactured by a method comprising steps of: providing a lens body; formulating a first solution, wherein the first solution is an ionic salt solution containing an alkali; placing the lens body in the first solution and reacting at 30 C. to 80 C.; formulating a second solution, wherein the second solution is an ionic salt solution containing at least one reactive dye; and placing the lens body in the second solution and reacting at 30 C. to 80 C.; wherein the at least one reactive dye reacts with the lens body to be fixed to a surface portion of the lens body.

18. The functional contact lens according to claim 17, wherein the dye layer has a thickness of 0.5 m to 40 m.

19. The functional contact lens according to claim 17, wherein the lens body comprises a concave surface and a convex surface, the dye layer extends from the concave surface toward an inside of the lens body by a first thickness and extends from the convex surface toward the inside of the lens body by a second thickness, and a sum of the first thickness and the second thickness is less than 40 m.

20. A functional contact lens comprising a lens body and a dye layer disposed on a surface portion of the lens body, and the lens body comprising: a concave surface, wherein the dye layer extends from the concave surface toward an inside of the lens body by a first thickness; and a convex surface, wherein the dye layer extends from the convex surface toward the inside of the lens body by a second thickness; wherein a sum of the first thickness and the second thickness is less than 40 m, and light having a wavelength in a range of 380 nm to 500 nm has a shielding ratio greater than 5% for the functional contact lens.

21. The functional contact lens according to claim 20, wherein a transmittance of light in a wavelength range of 380 nm to 500 nm approaches 0% in the functional contact lens, and the functional contact lens has a shielding ratio of less than 70% for light in a wavelength range 380 nm to 780 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a flow chart showing a method for dyeing a functional contact lens according to an embodiment of the present invention;

[0017] FIG. 2 is a schematic cross-sectional view of a functional contact lens according to an embodiment of the present invention;

[0018] FIG. 3A is a cross-sectional view of a functional contact lens according to an embodiment of the present invention;

[0019] FIG. 3B is a cross-sectional view of a lens body according to an embodiment of the present invention;

[0020] FIG. 4A is a graph showing the relationship between light wavelength and transmittance of a functional contact lens according to an embodiment of the present invention;

[0021] FIG. 4B is a graph showing the relationship between light wavelength and transmittance of a functional contact lens according to another embodiment of the present invention; and

[0022] FIG. 4C is a graph showing the relationship between light wavelength and transmittance of a lens body according to an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0023] The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

[0024] In the following description, the lens body or lens wet film body is defined as commercially available transparent, aqua blue or colored hydrogel or silicon hydrogel contact lenses. Hydrogel or hydrophobic may include any of the conventional hydrogel components may be selected form a group consisting of such as hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), methyl methacrylate (MMA), glyceryl methacrylate (GMA), N-vinyl pyrrolidone (NVP), N,N-dimethylacrylamide (DMA), N,N-diethylacrylamide, N-isopropylacrlamide, 2-hydroxyethyl acrylate, vinyl acetate, N-acryloymorpholine, 2-dimethlaminoethylacrylate, or a combination thereof.

[0025] Silicon hydrogel monomer can be silicon-containing monomers or other hydrophobic monomers capable of closing to the surface free energy of silicon hydrogel materials, such as MMA/ethyl methacrylate or styrene. The silicon-containing monomer may also be a material option of the silicon hydrogel constituting the lens body or the lens wet film body, and may be selected from a group consisting of, but not limited to, tris(trimethylphosphonioalkyl) methacrylate (TRIS), bis(trimethylsiloxy)methylsilylpropyl methacrylate, pentamethyldimethoxypropane-pentamethyldisiloxanepropyl methacrylate, pentamethyldisiloxanylmethylmethacrylate, tris (trimethylsiloxy) silylpropyloxyethyl methacrylate, tris(trimethylsiloxy)silylpropylmethacryloxyethylcarbamate (TSMC), tris(trimethylsiloxy)silypropyl glycerol methacrylate (SIGMA), tris(polydimethylsiloxy)silylpropyl methacrylate or a combination of thereof.

[0026] Ionic salt solution (containing alkali) includes one or more alkali such as sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium carbonate, boric acid, sodium tetraborate. In the dyeing of the lens body or the lens wet film body, the role of the alkali is to help the dye form a covalent bond with the lens, which has the effect of color fixing. The ionic salt solution of the alkali may contain 0.01 wt % to 4 wt % of an alkali.

[0027] The reactive dye of the ionic salt solution (containing reactive dye) is an azo reactive dye, which is non-toxic and meets the requirements for contact lens formulation, and meets the regulations of the US Food and Drug Administration (FDA), For example, Reactive Blue 21, Reactive Blue No 19, Reactive Yellow 15, Reactive Orange 78, Reactive Black 5, CI Reactive Yellow 86, CI Reactive Red 11, CI Reactive Red 180, CI Reactive Blue 163, and the like. The reactive dye is also a water-soluble dye having a reactive group on a molecular structure, which can be covalently bonded or hydrogen bonded to a hydroxyl group, an amino group or a carboxy hydroxyl group in a contact lens material. In the case of the vinyl hydrazine type reactive dye, the active group contained is sulfate of an ethylene fluorenyl group (D-SO2CHCH2) or a -hydroxyethyl oxime group. During dyeing, -hydroxyethyl sulfhydryl sulfate is eliminated in an alkaline medium to form an ethylene sulfhydryl group, which is then subjected to a nucleophilic addition reaction with a polymer hydroxyl group or an amino group to form a covalent bond. The ionic salt solution of the reactive dye composition may include one or more reactive dyes. The concentration of the dye may range from 0.01 wt % to 5 wt %.

[0028] Ionic salt solution is a commonly used buffer, and can be formulated bys such as sodium chloride, sodium hydrogen phosphate, sodium dihydrogen phosphate, sodium carbonate, potassium carbonate, boric acid, sodium tetraborate decahydrate, etc. The ionic salt solution may contain 0.01 wt % to 10 wt % of salt. The ionic salt solution provides osmotic pressure, which in turn controls the distribution of the alkali or reactive dye on the surface of the lens body, or the extent that the alkali or reactive dye enters the lens body. The ionic salt solution provides a higher osmotic pressure relative to the lens body, or a high tensile environment, such as an osmotic pressure of 300 to 800 mOsm/kg H.sub.2O.

[0029] FIG. 1 is a flow chart showing a method for dyeing a functional contact lens according to an embodiment of the present invention. As shown in FIG. 1, the method includes steps S910-S970. Step S910 includes: providing a lens body. The lens body or the lens wet film body may be a commercially available contact lens such as a commercially available transparent, water blue, or colored hydrogel or silicon hydrogel contact lens (hereinafter referred to as a lens).

[0030] Any hydrogel or silicon hydrogel contact lens having specific moisture content and oxygen permeability can be used in step S910. For example, a lens having a moisture content range of 20% to 80%, an oxygen permeability (DK) range of 810.sup.11 to 18810.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg) can be used. In an embodiment of the invention, the lens body of step S910 is a commercially available brand-A hydrogel lens having a moisture content of 38%. In another embodiment, the lens body of step S910 is a commercially available brand-B hydrogel lens having a moisture content of 58%. In yet another embodiment, the lens body of step S910 is a commercially available brand-C hydrogel color lens having a moisture content of 58%. In yet another embodiment, the lens body of step S910 is a commercially available brand-D silicon hydrogel lens having a moisture content of 56% and an oxygen permeability (DK) of 6010.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg). In yet another embodiment, the lens body of step S910 is a commercially available brand-E having a moisture content of 38% and an oxygen permeability (DK) of 10310.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg).

[0031] Thereafter as shown in FIG. 1, step S920 includes: formulating a first solution, wherein the first solution is an ionic salt solution containing an alkali. Sources of alkali include, but are not limited to, sodium carbonate, sodium hydrogencarbonate, sodium hydroxide, potassium carbonate. The ionic salt solution may be formulated by a salt such as sodium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium carbonate, potassium carbonate, boric acid, sodium tetraborate or the like, but is not limited thereto. Step S920 further includes: formulating an ionic salt solution having a concentration of 0.01 wt % to 10 wt %, and an ionic salt solution having a concentration of 0.01 wt % to 4 wt % alkali. The alkali ionic salt solution can be formulated with the aforementioned ionic salt solution.

[0032] Thereafter as shown in FIG. 1, step S930 includes: placing the lens body in the first solution and reacting at 30 C. to 80 C. Preferably, the reaction time is from 10 to 60 minutes. Step S930 further includes: providing an osmotic pressure, and further causing the lens body to be in a relatively high osmotic pressure environment. The osmotic pressure can be adjusted by the concentration of the ionic salt solution. In an embodiment of the invention, the osmotic pressure is 300 to 800 mOsm/kg H.sub.2O. In step S930, the alkali of the first solution affects the surface of the lens body based on the osmotic pressure, and can help the reactive dye of the subsequent step to form a covalent bond with the hydroxyl group, the amino group, and the carboxy hydroxyl group of the lens material, and therefore has a color fixing effect.

[0033] Thereafter as shown in FIG. 1, step S940 includes: formulating a second solution, wherein the second solution is an ionic salt solution containing at least one reactive dye. The reactive dyes is selected from a group consisting of black dye, yellow dye, orange dye, blue dye and red dye or a combination thereof, and/or selected from a group consisting of anti-blue light dye, anti-blue light absorber, and ultraviolet light absorber. In an embodiment of the invention, a vinyl hydrazine dye is employed. The reactive group vinyl fluorenyl of the vinyl hydrazine dye forms a covalent bond with the hydroxyl or amino group of the lens material to achieve dyeing of the lens. The ionic salt solution may be formulated by a salt such as sodium chloride, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium carbonate, potassium carbonate, boric acid, sodium tetraborate or the like, but is not limited thereto. Step S940 further includes: formulating an ionic salt solution having a concentration of 0.01 wt % to 10 wt %, and an ionic salt solution having 0.01 wt % to 5 wt % of the reactive dye. It can be understood that the second solution of step S940 and the first solution of step S920 can be formulated together with step S930.

[0034] Thereafter as shown in FIG. 1, step S950 includes: placing the lens body in the second solution and reacting at 30 C. to 80 C. Preferably, the reaction time is from 10 to 60 minutes. Step S950 further includes: providing an osmotic pressure, and further causing the lens body to be in a relatively high osmotic pressure environment. The osmotic pressure can be adjusted by the concentration of the ionic salt solution. In an embodiment of the invention, the osmotic pressure is 300 to 800 mOsm/kg H.sub.2O. The reactive dye of the second solution enters the lens body from the surface of the lens based on the osmotic pressure, and enters the lens body to varying degrees based on the osmotic pressure. The lens body is treated with the first solution containing an alkali in step S930, therefore in step S950, the reactive dye forms a covalent bond with the hydroxyl group, the amino group, and the carboxy hydroxyl group of the lens body and is fixed to the lens body. The procedure of alkali first and then dyeing also helps to increase the fixing rate of reactive dye and reduce the release of reactive dye.

[0035] The reactive dye bonded to the lens absorbs light of a specific wavelength range. Preferably, the specific wavelength range is in the blue wavelength range, so light having a specific wavelength is absorbed and blocked by the lens when visible light is incident on the dyed lens, and therefore the amount of light penetrating the lens is reduced.

[0036] It should be noted that although the reactive dye enters the lens body from the surface of the lens, the portion of the lens body to which the reactive dye is fixed is mainly the surface portion. Preferably, the reactive dye does not enter deep in the lens body.

[0037] Step S950 further includes: forming a dye layer on the surface of the lens body. As previously described, the reactive dye enters the lens body from the surface of the lens, as such the dye layer may have a different thickness depending on the extent to which the reactive dye enters the lens body. The extent to which the reactive dye enters the lens body and the thickness of the dye layer can be adjusted by the concentration of the ionic salt solution, the osmotic pressure, the concentration of the reactive dye, and the concentration of the alkali. The thickness of the dye layer can be determined based on the type of reactive dye and the desired light absorption.

[0038] Thereafter as shown in FIG. 1, step S960 includes: placing the lens body in the water for hydration. The water used is preferably RO water. Thereafter as shown in FIG. 1, step S970 includes: placing the lens body in buffer and sterilizing in parallel. As such, the resulting lens has an anti-blue light function and is suitable for use in environments where light is strong or full of blue light. Because blue light is the strongest part of the visible light that is closest to ultraviolet light, the adverse effects of blue light on the eyes can be reduced when the outdoor sportsmen, workers, and 3C product users wear the dyed lens in the embodiment of the present invention.

[0039] Refer to FIGS. 2 and 3A-3B. FIG. 2 is a schematic cross-sectional view of a functional contact lens according to an embodiment of the present invention. FIG. 3A is a cross-sectional photograph of a functional contact lens according to an embodiment of the present invention, wherein this photograph is taken by an optical microscope at a magnification of 100. As shown in FIG. 2, the functional contact lens 1 includes a lens body 10 and a dye layer 20. The lens body 10 has a concave surface 11 and a convex surface 12. The dye layer 20 is disposed on the surface of the lens body 10. Specifically, the dye layer 20 has a first thickness G.sub.1 on the concave surface 11 and a second thickness G.sub.2 on the convex surface 12. The physical photo is shown in FIG. 3A. Compared to the un-dyed lens body of FIG. 3B, the lens surface in FIG. 3A exhibits a color (i.e., dye layer) due to the fixation of the reactive dye. In the embodiment of the present invention, the total thickness of the dye layer 20 in the central region C of the functional contact lens 1 (i.e., the sum of the first thickness G.sub.1 and the second thickness G.sub.2) is 0.5 m to 40 m. Preferably, the total thickness is not greater than 40 m, and the first thickness G.sub.1 and the second thickness G.sub.2 may not be equal. For example, the dye layer 20 extends from the concave surface 11 of the lens body 10 toward the inside of the lens body 10 by a first thickness G.sub.1 of 9 m and extends from the convex surface 12 of the lens body 10 toward the inside of the lens body 10 by a second thickness G.sub.2 of 11 m. The dye layer 20 is located on the surface portion of the functional contact lens 1; therefore, even if the central portion C of the lens is inconsistent with the edge region in thickness, the overall color of the lens can be nearly uniform without the problem in which the central region C and the edge region are significantly different in color due to dyeing (i.e., annular color difference). The central region C shown in FIG. 2 is merely an illustration, and does not limit the size of the central region.

[0040] The conditions and results of dyeing according to steps S910 to S970 are further illustrated by Embodiments 1 to 5 below.

[0041] Hereunder the Embodiment 1 is described. In step S910, a commercially available brand-A hydrogel lens having a moisture content of 38% is used. In step S920, a first solution containing sodium hydroxide having an osmotic pressure of 350, 450, 550, 650, 750 mOsm/kg H.sub.2O is formulated. In step S930, five lenses (i.e., brand-A-1, brand-A-2, brand-A-3, brand-A-4, and brand-A-5) are sequentially placed in the first solution having five different osmotic pressures. In step S940, a first solution containing a reactive dye having an osmotic pressure of 350, 450, 550, 650, 750 mOsm/kg H.sub.2O is formulated, wherein the concentration of the reactive dye is 2 wt %. In step S950, the five lenses (i.e., brand-A-1, brand-A-2, brand-A-3, brand-A-4, and brand-A-5) are sequentially placed in the second solution having five different osmotic pressures. In step S960, the lens body is placed in RO water for hydration. In step S970, the lens body is placed in a buffer and sterilized in parallel. After the foregoing steps, the total thickness of the dye layer in the central portion of the lens is observed by using an optical microscope, and the color of the buffer after sterilization is observed. The results are shown in Table 1-1 below. As shown in Table 1-1, the thickness of the dye layer can be controlled by adjusting the osmotic pressure. Further, the reactive dye is well fixed on the surface of the lens.

[0042] Hereunder the Control Group 1 is described. In the control group, a commercially available brand-A hydrogel lens having a moisture content of 38% is also used, except that RO water is used to formulate a RO aqueous solution of reactive dye (concentration: 2 wt %) and a RO aqueous solution of alkali (hydrogen hydroxide) and the dyeing is performed with a procedure of dye treatment first and then alkali fixation. The temperature and time conditions of dye treatment and alkali fixation are the same as those in Embodiment 1. The thickness of the dye layer and the color of the buffer are also observed in the Control Group 1, and the results are shown in Table 1-2 below. As shown in Table 1-2, the thickness of the dye layer in the Control Group 1 is much greater than that in Embodiment 1. Since the lens body generally has a thickness of 80 m to 100 m, the results in Table 1-2 show that the Control Group 1 cannot control the dye layer on the surface portion of the lens, so the dyeing may cause a significant color difference (i.e., annular color difference) between the central region and the edge region, and therefore the appearance is affected. Further, the reactive dye is not well fixed on the surface of the lens.

TABLE-US-00001 TABLE 1-1 First First Second Second solution solution solution solution Total Buffer (ionic salt osmotic (ionic salt osmotic thickness color after solution pressure solution pressure of dye sterilization Embodiment containing Heating (mOsm/kg containing Heating (mOsm/kg layer (reactive 1 an alkali) temperature/time H.sub.2O) reactive dye) temperature/time H.sub.2O) (m) dye release) Brand-A-1 sodium 60 C./30 min 350 reactive dye 60 C./30 min 350 21 m transparent hydroxide 2 wt % clarification Brand-A-2 sodium 60 C./30 min 450 reactive dye 60 C./30 min 450 18 m transparent hydroxide 2 wt % clarification Brand-A-3 sodium 60 C./30 min 550 reactive dye 60 C./30 min 550 12 m transparent hydroxide 2 wt % clarification Brand-A-4 sodium 60 C./30 min 650 reactive dye 60 C./30 min 650 8 m transparent hydroxide 2 wt % clarification Brand-A-5 sodium 60 C./30 min 750 reactive dye 60 C./30 min 750 2 m transparent hydroxide 2 wt % clarification

TABLE-US-00002 TABLE 1-2 Osmotic pressure of Osmotic RO RO aqueous pressure of Total Buffer aqueous solution of alkaline RO thickness color after solution of reactive dye Alkaline solution of dye sterilization Control reactive Heating (mOsm/kg RO Heating (mOsm/kg layer (reactive Group 1 dye temperature/time H.sub.2O) solution temperature/time H.sub.2O) (m) dye release) Brand-A-1 reactive 60 C./30 min sodium 60 C./30 min 70 m light yellow dye 2 wt % hydroxide Brand-A-2 reactive 60 C./30 min sodium 60 C./30 min 72 m light yellow dye 2 wt % hydroxide Brand-A-3 reactive 60 C./30 min sodium 60 C./30 min 70 m light yellow dye 2 wt % hydroxide Brand-A-4 reactive 60 C./30 min sodium 60 C./30 min 67 m light yellow dye 2 wt % hydroxide Brand-A-5 reactive 60 C./30 min sodium 60 C./30 min 73 m light yellow dye 2 wt % hydroxide

[0043] Hereunder the Embodiment 2 is described. In step S910, a commercially available brand-B hydrogel lens having a moisture content of 58% is used. The step S920 in the Embodiment 2 is the same as the step S920 in the Embodiment 1. In step S930, five lenses (i.e., brand-B-1, brand-B-2, brand-B-3, brand-B-4, and brand-B-5) are sequentially placed in the first solution having five different osmotic pressures. The step S940 in the Embodiment 2 is the same as the step S940 in the Embodiment 1. In step S950, the five lenses (i.e., brand-B-1, brand-B-2, brand-B-3, brand-B-4, and brand-B-5) are sequentially placed in the second solution. The steps S960 and S970 in the Embodiment 2 are the same as the steps S960 and S970 in the Embodiment 1, respectively. After the foregoing steps, the total thickness of the dye layer in the central portion of the lens is observed by using an optical microscope, and the color of the buffer after sterilization is observed. The results are shown in Table 2-1 below. As shown in Table 2-1, the thickness of the dye layer can be controlled by adjusting the osmotic pressure. Further, the reactive dye is well fixed on the surface of the lens.

[0044] Hereunder the Control Group 2 is described. In the control group, a commercially available brand-B hydrogel lens having a moisture content of 58% is also used, except that RO water is used to formulate a RO aqueous solution of reactive dye (concentration: 2 wt %) and a RO aqueous solution of alkali (hydrogen hydroxide) and the dyeing is performed with a procedure of dye treatment first and then alkali fixation. The temperature and time conditions of dye treatment and alkali fixation are the same as those in Embodiment 2. As shown in Table 2-2, the thickness of the dye layer in the Control Group 2 is much greater than that in Embodiment 2. The Control Group 2 cannot control the dye layer on the surface portion of the lens, and the reactive dye is not well fixed on the surface of the lens.

TABLE-US-00003 TABLE 2-1 First First Second Second solution solution solution solution Total Buffer (ionic salt osmotic (ionic salt osmotic thickness color after solution pressure solution pressure of dye sterilization Embodiment containing Heating (mOsm/kg containing Heating (mOsm/kg layer (reactive 2 an alkali) temperature/time H.sub.2O) reactive dye) temperature/time H.sub.2O) (m) dye release) Brand-B-1 sodium 60 C./30 min 350 reactive dye 60 C./30 min 350 20 m transparent hydroxide 2 wt % clarification Brand-B-2 sodium 60 C./30 min 450 reactive dye 60 C./30 min 450 17 m transparent hydroxide 2 wt % clarification Brand-B-3 sodium 60 C./30 min 550 reactive dye 60 C./30 min 550 15 m transparent hydroxide 2 wt % clarification Brand-B-4 sodium 60 C./30 min 650 reactive dye 60 C./30 min 650 10 m transparent hydroxide 2 wt % clarification Brand-B-5 sodium 60 C./30 min 750 reactive dye 60 C./30 min 750 5 m transparent hydroxide 2 wt % clarification

TABLE-US-00004 TABLE 2-2 Osmotic pressure of Osmotic RO RO aqueous pressure of Total Buffer aqueous solution of alkaline RO thickness color after solution of reactive dye Alkaline solution of dye sterilization Control reactive Heating (mOsm/kg RO Heating (mOsm/kg layer (reactive Group 2 dye temperature/time H.sub.2O) solution temperature/time H.sub.2O) (m) dye release) Brand-B-1 reactive 60 C./30 min sodium 60 C./30 min 78 m light yellow dye 2 wt % hydroxide Brand-B-2 reactive 60 C./30 min sodium 60 C./30 min 76 m light yellow dye 2 wt % hydroxide Brand-B-3 reactive 60 C./30 min sodium 60 C./30 min 77 m light yellow dye 2 wt % hydroxide Brand-B-4 reactive 60 C./30 min sodium 60 C./30 min 76 m light yellow dye 2 wt % hydroxide Brand-B-5 reactive 60 C./30 min sodium 60 C./30 min 79 m light yellow dye 2 wt % hydroxide

[0045] Hereunder the Embodiment 3 is described. In step S910, a commercially available brand-C hydrogel color lens having a moisture content of 58% is used. The step S920 in the Embodiment 3 is the same as the step S920 in the above Embodiments. In step S930, five lenses (i.e., brand-C-1, brand-C-2, brand-C-3, brand-C-4, and brand-C-5) are sequentially placed in the first solution having five different osmotic pressures. The step S940 in the Embodiment 3 is the same as the step S940 in the above Embodiments. In step S950, the five lenses (i.e., brand-C-1, brand-C-2, brand-C-3, brand-C-4, and brand-C-5) are sequentially placed in the second solution having five different osmotic pressures. The steps S960 and S970 in the Embodiment 3 are the same as the steps S960 and S970 in the above Embodiments, respectively. After the foregoing steps, the total thickness of the dye layer in the central portion of the lens is observed by using an optical microscope, and the color of the buffer after sterilization is observed. The results are shown in Table 3-1 below. As shown in Table 3-1, the thickness of the dye layer can be controlled by adjusting the osmotic pressure. Further, the reactive dye is well fixed on the surface of the lens.

[0046] Hereunder the Control Group 3 is described. In the control group, a commercially available brand-C hydrogel color lens having a moisture content of 58% is also used, except that RO water is used to formulate a RO aqueous solution of reactive dye (concentration: 2 wt %) and a RO aqueous solution of alkali (hydrogen hydroxide) and the dyeing is performed with a procedure of dye treatment first and then alkali fixation. The temperature and time conditions of dye treatment and alkali fixation are the same as those in Embodiment 3. As shown in Table 3-2, the thickness of the dye layer in the Control Group 3 is much greater than that in Embodiment 3. The Control Group 3 cannot control the dye layer on the surface portion of the lens, and the reactive dye is not well fixed on the surface of the lens.

TABLE-US-00005 TABLE 3-1 First First Second Second solution solution solution solution Total Buffer (ionic salt osmotic (ionic salt osmotic thickness color after solution pressure solution pressure of dye sterilization Embodiment containing Heating (mOsm/kg containing Heating (mOsm/kg layer (reactive 3 an alkali) temperature/time H.sub.2O) reactive dye) temperature/time H.sub.2O) (m) dye release) Brand-C-1 sodium 60 C./30 min 350 reactive dye 60 C./30 min 350 21 m transparent hydroxide 2 wt % clarification Brand-C-2 sodium 60 C./30 min 450 reactive dye 60 C./30 min 450 17 m transparent hydroxide 2 wt % clarification Brand-C-3 sodium 60 C./30 min 550 reactive dye 60 C./30 min 550 16 m transparent hydroxide 2 wt % clarification Brand-C-4 sodium 60 C./30 min 650 reactive dye 60 C./30 min 650 12 m transparent hydroxide 2 wt % clarification Brand-C-5 sodium 60 C./30 min 750 reactive dye 60 C./30 min 750 4 m transparent hydroxide 2 wt % clarification

TABLE-US-00006 TABLE 3-2 Osmotic pressure of Osmotic RO RO aqueous pressure of Total Buffer aqueous solution of alkaline RO thickness color after solution of reactive dye Alkaline solution of dye sterilization Control reactive Heating (mOsm/kg RO Heating (mOsm/kg layer (reactive Group 3 dye temperature/time H.sub.2O) solution temperature/time H.sub.2O) (m) dye release) Brand-C-1 reactive 60 C./30 min sodium 60 C./30 min 75 m light yellow dye 2 wt % hydroxide Brand-C-2 reactive 60 C./30 min sodium 60 C./30 min 76 m light yellow dye 2 wt % hydroxide Brand-C-3 reactive 60 C./30 min sodium 60 C./30 min 76 m light yellow dye 2 wt % hydroxide Brand-C-4 reactive 60 C./30 min sodium 60 C./30 min 78 m light yellow dye 2 wt % hydroxide Brand-C-5 reactive 60 C./30 min sodium 60 C./30 min 74 m light yellow dye 2 wt % hydroxide

[0047] Hereunder the Embodiment 4 is described. In step S910, a commercially available brand-D silicon hydrogel lens having a moisture content of 58% and an oxygen permeability (DK) of 6010.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg) is used. The step S920 in the Embodiment 4 is the same as the step S920 in the above Embodiments. In step S930, five lenses (i.e., brand-D-1, brand-D-2, brand-D-3, brand-D-4, and brand-D-5) are sequentially placed in the first solution having five different osmotic pressures. The step S940 in the Embodiment 4 is the same as the step S940 in the above Embodiments. In step S950, the five lenses (i.e., brand-D-1, brand-D-2, brand-D-3, brand-D-4, and brand-D-5) are sequentially placed in the second solution having five different osmotic pressures. The steps S960 and S970 in the Embodiment 4 are the same as the steps S960 and S970 in the above Embodiments, respectively. After the foregoing steps, the total thickness of the dye layer in the central portion of the lens is observed by using an optical microscope, and the color of the buffer after sterilization is observed. The results are shown in Table 4-1 below. As shown in Table 4-1, the thickness of the dye layer can be controlled by adjusting the osmotic pressure. Further, the reactive dye is well fixed on the surface of the lens.

[0048] Hereunder the Control Group 4 is described. In the control group, a commercially available brand-D silicon hydrogel lens having a moisture content of 58% and an oxygen permeability (DK) of 6010.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg) is also used, except that RO water is used to formulate a RO aqueous solution of reactive dye and a RO aqueous solution of alkali and the dyeing is performed with a procedure of dye treatment first and then alkali fixation. The temperature and time conditions of dye treatment and alkali fixation are the same as those in Embodiment 4. As shown in Table 4-2, the thickness of the dye layer in the Control Group 4 is much greater than that in Embodiment 4. The Control Group 4 cannot control the dye layer on the surface portion of the lens, and the reactive dye is not well fixed on the surface of the lens.

TABLE-US-00007 TABLE 4-1 First First Second Second solution solution solution solution Total Buffer (ionic salt osmotic (ionic salt osmotic thickness color after solution pressure solution pressure of dye sterilization Embodiment containing Heating (mOsm/kg containing Heating (mOsm/kg layer (reactive 4 an alkali) temperature/time H.sub.2O) reactive dye) temperature/time H.sub.2O) (m) dye release) Brand-D-1 sodium 60 C./30 min 350 reactive dye 60 C./30 min 350 18 m transparent hydroxide 2 wt % clarification Brand-D-2 sodium 60 C./30 min 450 reactive dye 60 C./30 min 450 14 m transparent hydroxide 2 wt % clarification Brand-D-3 sodium 60 C./30 min 550 reactive dye 60 C./30 min 550 11 m transparent hydroxide 2 wt % clarification Brand-D-4 sodium 60 C./30 min 650 reactive dye 60 C./30 min 650 9 m transparent hydroxide 2 wt % clarification Brand-D-5 sodium 60 C./30 min 750 reactive dye 60 C./30 min 750 3 m transparent hydroxide 2 wt % clarification

TABLE-US-00008 TABLE 4-2 Osmotic pressure of Osmotic RO RO aqueous pressure of Total Buffer aqueous solution of alkaline RO thickness color after solution of reactive dye Alkaline solution of dye sterilization Control reactive Heating (mOsm/kg RO Heating (mOsm/kg layer (reactive Group 4 dye temperature/time H.sub.2O) solution temperature/time H.sub.2O) (m) dye release) Brand-D-1 reactive 60 C./30 min sodium 60 C./30 min 60 m light yellow dye 2 wt % hydroxide Brand-D-2 reactive 60 C./30 min sodium 60 C./30 min 62 m light yellow dye 2 wt % hydroxide Brand-D-3 reactive 60 C./30 min sodium 60 C./30 min 65 m light yellow dye 2 wt % hydroxide Brand-D-4 reactive 60 C./30 min sodium 60 C./30 min 59 m light yellow dye 2 wt % hydroxide Brand-D-5 reactive 60 C./30 min sodium 60 C./30 min 63 m light yellow dye 2 wt % hydroxide

[0049] Hereunder the Embodiment 5 is described. In step S910, a commercially available brand-E silicon hydrogel lens having a moisture content of 38% and an oxygen permeability (DK) of 10310.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg) is used. The step S920 in the Embodiment 4 is the same as the step S920 in the above Embodiments. In step S930, five lenses (i.e., brand-E-1, brand-E-2, brand-E-3, brand-E-4, and brand-E-5) are sequentially placed in the first solution having five different osmotic pressures. The step S940 in the Embodiment 5 is the same as the step S940 in the above Embodiments. In step S950, the five lenses (i.e., brand-E-1, brand-E-2, brand-E-3, brand-E-4, and brand-E-5) are sequentially placed in the second solution having five different osmotic pressures. The steps S960 and S970 in the Embodiment 5 are the same as the steps S960 and S970 in the above Embodiments, respectively. After the foregoing steps, the total thickness of the dye layer in the central portion of the lens is observed by using an optical microscope, and the color of the buffer after sterilization is observed. The results are shown in Table 4-1 below. As shown in Table 5-1, the thickness of the dye layer can be controlled by adjusting the osmotic pressure. Further, the reactive dye is well fixed on the surface of the lens.

[0050] Hereunder the Control Group 5 is described. In the control group, a commercially available brand-E silicon hydrogel lens having a moisture content of 38% and an oxygen permeability (DK) of 10310.sup.11 (cm.sup.2/sec) (ml O.sub.2/mlmm Hg) is also used, except that RO water is used to formulate a RO aqueous solution of reactive dye and a RO aqueous solution of alkali and the dyeing is performed with a procedure of dye treatment first and then alkali fixation. The temperature and time conditions of dye treatment and alkali fixation are the same as those in Embodiment 5. As shown in Table 5-2, the thickness of the dye layer in the Control Group 5 is much greater than that in Embodiment 5. The Control Group 5 cannot control the dye layer on the surface portion of the lens, and the reactive dye is not well fixed on the surface of the lens.

TABLE-US-00009 TABLE 5-1 First First Second Second solution solution solution solution Total Buffer (ionic salt osmotic (ionic salt osmotic thickness color after solution pressure solution pressure of dye sterilization Embodiment containing Heating (mOsm/kg containing Heating (mOsm/kg layer (reactive 5 an alkali) temperature/time H.sub.2O) reactive dye) temperature/time H.sub.2O) (m) dye release) Brand-E-1 sodium 60 C./30 min 350 reactive dye 60 C./30 min 350 18 m transparent hydroxide 2 wt % clarification Brand-E-2 sodium 60 C./30 min 450 reactive dye 60 C./30 min 450 15 m transparent hydroxide 2 wt % clarification Brand-E-3 sodium 60 C./30 min 550 reactive dye 60 C./30 min 550 12 m transparent hydroxide 2 wt % clarification Brand-E-4 sodium 60 C./30 min 650 reactive dye 60 C./30 min 650 7 m transparent hydroxide 2 wt % clarification Brand-E-5 sodium 60 C./30 min 750 reactive dye 60 C./30 min 750 1 m transparent hydroxide 2 wt % clarification

TABLE-US-00010 TABLE 5-2 Osmotic pressure of Osmotic RO RO aqueous pressure of Total Buffer aqueous solution of alkaline RO thickness color after solution of reactive dye Alkaline solution of dye sterilization Control reactive Heating (mOsm/kg RO Heating (mOsm/ layer (reactive Group 5 dye temperature/time H.sub.2O) solution temperature/time kg H.sub.2O) (m) dye release) Brand-E-1 reactive 60 C./30min sodium 60 C./30 min 68 m light yellow dye 2 wt % hydroxide Brand-E-2 reactive 60 C./30 min sodium 60 C./30 min 69 m light yellow dye 2 wt % hydroxide Brand-E-3 reactive 60 C./30 min sodium 60 C./30 min 65 m light yellow dye 2 wt % hydroxide Brand-E-4 reactive 60 C./30 min sodium 60 C./30 min 64 m light yellow dye 2 wt % hydroxide Brand-E-5 reactive 60 C./30 min sodium 60 C./30 min 67 m light yellow dye 2 wt % hydroxide

[0051] In summary, the dyeing method of the embodiment of the present invention can be applied to various materials and the lenses having different moisture contents and different oxygen permeability, and the reactive dyes are not significantly released and no safety problem. The formulated functional contact lens has higher market acceptance because the dyeing layer is located on the surface portion of the lens, thereby improving the color uniformity of the appearance of the lens, and the lens is more beautiful.

[0052] The functional contact lens of the embodiment of the invention and the functional contact lens produced by the dyeing method embodiment have the function of anti-blue light. Further, by adjusting the ratio of each reactive dye (such as black, yellow, orange, blue, red dye) and the amount of reactive dyes, different absorption/transmission ratios of the lenses for different wavelength ranges of light is obtained. The effects of different reactive dyes on the light transmittance are exemplified below by Embodiments 6 and 7.

[0053] Hereunder the Embodiment 6 is described. According to the foregoing steps S910 to S970, the second solution is formulated with a yellow dye for dyeing. Then, the obtained functional contact lens is tested for light transmittance, and the results are shown in FIG. 4A. As shown in FIG. 4A, the functional contact lens of Embodiment 6 absorbs light of a specific wavelength range. This specific wavelength range is in the blue wavelength range, and the shielding rate of light in the wavelength range of 380 nm to 500 nm is observed to be greater than 5%. Preferably, the transmittance of light in the wavelength range of 380 nm to 500 nm is also reduced by about 20%. Based on this result, the functional contact lens of the embodiments of the present invention has an anti-blue light effect.

[0054] Hereunder the Embodiment 7 is described. According to the foregoing steps S910 to S970, a plurality of reactive dyes is combined to formulate a second solution having a reactive dye concentration of 2 wt % for dyeing. Then, the obtained functional contact lens is tested for light transmittance, and the results are shown in FIG. 4B. As shown in FIG. 4B, the functional contact lens of Embodiment 7 absorbs light of a specific wavelength range, wherein the shielding ratio of the light having a wavelength range of 380 nm to 780 nm is at most 70% and preferably not more than 70%, and the transmittance of light having a wavelength range of 380 nm to 500 nm approaches zero (0%). Based on this result, the functional contact lens of the embodiments of the present invention are suitable as a sun contact lens to protect the wearer from the adverse effects of strong light on the eyes. In addition, because also having the effect of improving visual contrast sensitivity, reducing reflection glare, and increasing color contrast, the functional contact lens of the embodiments of the present invention is also suitable for outdoor sports, which can improve sports performance.

[0055] Hereunder the Control Group 6 is described. As shown in FIG. 4C, compared with Embodiment 6 and 7, visible light has a transmittance of greater than 90% in the un-dyed lens body, and therefore, light in the blue wavelength range has a greater probability of penetrating the lens and affecting the eye.

[0056] In summary, the present invention provides a method for dyeing a functional contact lens, in which the thickness of the dye layer is controlled by controlling the alkali or reactive dye on the surface portion of the lens by the high osmotic pressure of the ions. The procedure of alkali first and then dyeing allows the reactive dye to be effectively fixed to the surface portion of the lens to reduce dye release. The dyeing method of the invention helps to overcome the annular color difference of the lens color caused by the difference in thickness of the contact lens and improves the color uniformity, thereby providing a contact lens which is both aesthetic and anti-blue light.

[0057] The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto. That is, the simple equivalent change and modifications according to the scope of the present invention and the description of the invention are still within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the Abstract and Title are only used to assist in the search of patent documents and are not intended to limit the scope of the invention. In addition, the terms first and second as used in the specification or the scope of the patent application are used only to name the elements or to distinguish different embodiments or ranges, and are not intended to limit the upper or lower limit number of elements.