OPHTHALMIC LENS COMPRISING AN OXAZOLONE

Abstract

The present invention relates to ophthalmic lenses comprising an oxazolone, a preparation method thereof and the use of an oxazolone in an ophthalmic lens to absorb blue light.

Claims

1.-16. (canceled)

17. An ophthalmic lens comprising: a plastic base; and an oxazolone, wherein the oxazolone is represented by the following formula (I): ##STR00011## wherein A is a 5-membered ring selected from one of the following: ##STR00012## each R.sub.1 is independently selected from halogen, (C.sub.1-6)alkyl, (C.sub.1-6)haloalkyl, —OH, —OR, —NH.sub.2, —NH((C.sub.1-6)alkyl), —N((C.sub.1-6)alkyl).sub.2, —NO.sub.2, —CN, —NH—C(O)—(C.sub.1-6)alkyl and —O—C(O)—(C.sub.1-6)alkyl; each R.sub.2 is independently selected from halogen, (C.sub.1-6)alkyl, (C.sub.1-6)haloalkyl, —OH, —OR, —NH.sub.2, —NH((C.sub.1-6)alkyl), —N((C.sub.1-6)alkyl).sub.2, —NO.sub.2, —CN, —NH—C(O)—(C.sub.1-6)alkyl and —O—C(O)—(C.sub.1-6)alkyl; R is (C.sub.1-6)alkyl or (C.sub.1-6)haloalkyl; n is 0, 1, 2, 3, 4 or 5; and m is 0, 1, 2, 3, 4 or 5.

18. The ophthalmic lens of claim 17, wherein each R.sub.1 is independently selected from Cl, Br, F, —CF.sub.3, —OH, —OCH.sub.3, —NH.sub.2, —N(CH.sub.3).sub.2, —CH.sub.3, —C.sub.2H.sub.5, —NO.sub.2, —CN, and —O—C(O)—CH.sub.3.

19. The ophthalmic lens of claim 17, wherein each R.sub.2 is independently selected from Cl, Br, F, —CF.sub.3, —OH, —OCH.sub.3, —NH.sub.2, —N(CH.sub.3).sub.2, —CH.sub.3, —C.sub.2H.sub.5, —NO.sub.2, —CN, and —O—C(O)—CH.sub.3.

20. The ophthalmic lens of claim 17, wherein the oxazolone is represented by the following formula (II) or (III): ##STR00013## wherein R.sub.1, R.sub.2, n and m are as defined in claim 17.

21. The ophthalmic lens of claim 17, wherein: each R.sub.2 is independently selected from Cl, F, —CF.sub.3, NO.sub.2, —OH and —OCH.sub.3; n is 0; and m is 0, 1 or 2.

22. The ophthalmic lens of claim 21, wherein each R.sub.2 is independently selected from Cl, F and CF.sub.3.

23. The ophthalmic lens of claim 17, wherein the oxazolone is represented by one of the following formula (IVa)-(IVk): ##STR00014## ##STR00015##

24. The ophthalmic lens of claim 17, wherein the stereochemistry of the carbon-carbon double bond in the oxazolone is (Z).

25. The ophthalmic lens of claim 17, wherein the oxazolone has a maximum absorption wavelength (λmax) lower than 400 nm, as measured on a 10 ppm solution of oxazolone in ethanol.

26. The ophthalmic lens of claim 17, wherein the oxazolone is included in the plastic base or is included in a separate layer coated on a surface of the plastic base.

27. The ophthalmic lens of claim 17, wherein the oxazolone is encapsulated within nanoparticles.

28. The ophthalmic lens of claim 17, wherein the amount of oxazolone is 0.001 to 5% by weight based on the weight of the plastic base when the oxazolone is included in the plastic base or on the weight of a separate layer when the oxazolone is included in a separate layer coated on a surface of the plastic base.

29. The ophthalmic lens of claim 17, wherein the ophthalmic lens further comprises a benzotriazole UV-absorber or a mixture thereof.

30. The ophthalmic lens of claim 29, wherein the benzotriazole UV-absorber is selected from 2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotriazole, 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole, and mixtures thereof.

31. The ophthalmic lens of claim 29, wherein the total amount of benzotriazole UV-absorber is 0.001 to 2% by weight based on the weight of the plastic base.

32. The ophthalmic lens of claim 17, wherein light cut is higher than 402 nm.

33. The ophthalmic lens of claim 17, wherein Yellow Index of light transmitted through said ophthalmic lens is lower than 10.

34. The ophthalmic lens of claim 17, wherein the average transmittance of the ophthalmic lens over the range 420-450 nm is less than 85%, wherein the average transmittance is measured on a bare lens.

35. A process for preparing the ophthalmic lens of claim 17, comprising the steps of: a) providing monomers or oligomers from which the plastic base can be prepared; b) mixing the monomers or oligomers, the oxazolone and a catalyst suitable for the polymerization of the monomers and oligomers to form a polymerizable liquid composition; c) curing the polymerizable liquid composition.

36. A method of absorbing blue light comprising: a) obtaining an ophthalmic lens comprising an oxazolone as defined in claim 17; b) positioning the lens in a position where it absorbs blue light.

Description

FIGURES

[0097] FIGS. 1 and 2 are graphs of absorbance (Abs) as a function of wavelength (λ, in nm) for a solution of 1 mg of oxazolone of formula (IVa) to (IVk) in 100 mL of ethanol.

[0098] MEASURING METHODS

[0099] The following measures are carried out on a lens that is 2 mm thick in its center and that has been cleaned with isopropyl alcohol.

[0100] The light cut, transmittance, yellow index and colorimetric coefficients of the lens were determined with a spectrophotometer (Cary60).

[0101] The light cut, yellow index and TvD65 are measured immediately after manufacture and after accelerated ageing in Q-Sun cell (80 hours of UV light exposition in a Xenon test chamber Q-SUN® Xe-3 from Q-LAB at 23° C. (±5° C.) and 20% (±5%) of relative humidity).

[0102] The light cut of the lens is determined under normal incident light by plotting the graph of the transmittance percentage of the lens as a function of the wavelength. The light cut of the material can be read on the graph as the wavelength corresponding to a transmittance of 1%.

[0103] The transmittance (TvD65) is determined under normal incident light (standard illuminant D65).

[0104] The Yellow Index (YI) is measured according to ASTM D-1925.

[0105] The average (or mean) light transmittance over 420-450 nm range (TmB1%) is computed from transmittance curve measured according to ISO 8980-3-2003.

[0106] The average (or mean) light transmittance over 465-495 nm range (TmB2%) is computed from transmittance curve measured according to ISO 8980-3-2003.

[0107] Colorimetric coefficients of the lenses of the invention are measured according to the international colorimetric system CIE L*a*b* and L*C*H*, i.e. calculated between 380 and 780 nm, taking the standard illuminant D65 at angle of incidence 15° and the observer into account (angle of 10°).

[0108] Materials

[0109] In the examples, the following compounds are used:

TABLE-US-00001 Function Chemical CAS No. Supplier Monomer ISO1 bis(isocyanatomethyl) 74091-64-8 (diisocyanate) bicyclo[2.2.1]heptane Monomer pentaerythritol tetrakis 7575-23-7 THIO1 (3-mercaptopropionate) (polythiol) Monomer 1,2-bis[(2-mercaptoethyl) 131538-00-6 THIO2 thio]-3-mercaptopropane (polythiol) Monomer ISO2 xylylene diisocyanate 3634-83-1 (diisocyanate) Catalyst Dimethyltin dichloride 753-73-1 Honjo (DMC) Chemical Mold release Zelec ® UN — Stepan agent Company UV Absorber Seesorb ® 703 3896-11-6 Shipro (benzotriazole) Kasei Kaisha UV Absorber Seesorb ® 709 3147-75-9 Shipro (benzotriazole) Kasei Kaisha UV Absorber Seesorb ® 701 2440-22-4 Shipro (benzotriazole) Kasei Kaisha UV Absorber Eversorb ® 109 83044-89-7 Everlight (benzotriazole) 83044-90-0 Chemical UV Absorber Sunsorb ® 327 3864-99-1 Everspring (benzotriazole) Chemical UV Absorber Tinuvin ® 928 73936-91-1 BASF (benzotriazole) Light stabilizer Tinuvin ® 144 63843-89-0 BASF

Example 1: Preparation of Oxazolone (IVa)

[0110] ##STR00009## ##STR00010##

Preparation of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholin-4-ium chloride (3)

[0111] To a solution of 2-chloro-4,6-dimethoxy-1,3,5-triazine (1) (4 g, 0.23 mol) in THF (200 ml), morpholine (2) (3.4 ml, 0.031 mol) was added dropwise. The reaction was stirred at room temperature (20-25° C.) for 2 h. The resulting suspension was filtered and the solid was dried to yield 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholin-4-ium chloride (3) as an organic salt.

Preparation of Oxazolone (IVa)

[0112] 2.7 g of hippuric acid (4a) (0.015 mol) was dissolved in THF (130 ml), followed by addition of salt (3) (0.015 mol). The mixture was stirred for 2 h at room temperature (20-25° C.). Subsequently, the reaction was charged with benzaldehyde (6a) (1.93 g, 0.014 mol) and THF (20 ml), then refluxed (75° C.) for 2 h. After cooling the mixture to room temperature, the remaining undissolved organic salts in the mixture were filtered off. The filtrate was then concentrated under vacuum and re-dissolved using EtOAc. It was washed with an aqueous solution of Na.sub.2CO.sub.3 and water, then dried over Na.sub.2SO.sub.4, filtered and evaporated under vacuum. Finally, the obtained solid was re-crystallized in acetone to afford oxazolone (IVa) as a yellowish crystal.

Example 2: Preparation of Oxazolone (IVb) to (IVk)

[0113] Oxazolone (IVb) to (IVk) were obtained according to example 1 by replacing benzaldehyde (6a) with the corresponding substituted benzaldehyde, as shown in table below.

TABLE-US-00002 substituted benzaldehyde used in synthesis oxazolone (IVb) 4-chlorobenzaldehyde oxazolone (IVc) 3,4-dimethoxybenzaldehyde oxazolone (IVd) 4-fluorobenzaldehyde oxazolone (IVe) 4-hydroxybenzaldehyde oxazolone (IVf) 4-trifluoromethylbenzaldehyde Oxazolone (IVg) 3-chlorobenzaldehyde Oxazolone (IVh) 4-methoxybenzaldehyde Oxazolone (IVj) 4-dimethylaminobenzaldehyde Oxazolone (IVk) 4-nitrobenzaldehyde

Example 3: Absorption Properties of Oxazolone (IVa)-(IVk)

[0114] The absorbance (A) as a function of wavelength (A) was measured for a solution of 1 mg of oxazolone of formula (IVa) to (IVk) in 100 mL of ethanol (see FIGS. 1 and 2). The maximum absorption wavelength (Amax) for each oxazolone is given in the table below:

TABLE-US-00003 λmax Aldehyde used in synthesis (nm) oxazolone (IVa) benzaldehyde (unsubstituted) 362 oxazolone (IVb) 4-chlorobenzaldehyde 366 oxazolone (IVc) 3,4-dimethoxybenzaldehyde 400 oxazolone (IVd) 4-fluorobenzaldehyde 362 oxazolone (IVe) 4-hydroxybenzaldehyde 383 oxazolone (IVf) 4-trifluoromethylbenzaldehyde 359 Oxazolone (IVg) 3-chlorobenzaldehyde 361 Oxazolone (IVh) 4-methoxybenzaldehyde 383 Oxazolone (IVj) 4-dimethylaminobenzaldehyde 469 Oxazolone (IVk) 4-nitrobenzaldehyde 375

[0115] All compounds (except (IVj)) exhibit a maximum absorption wavelength (Amax) in the range of 350 to 400 nm. Indeed, these compounds may absorb UV-A and blue violet light, without imparting a yellow colour to ophthalmic lenses.

[0116] Compound (IVj) exhibits a maximum absorption wavelength at 469 nm, in the range of blue light associated with circadian rhythm: such compound may be used to prepare ophthalmic lenses that filter out blue light around 480 nm, adapted to shifted workers or travellers.

Example 4: Preparation of Compositions to Obtain an Ophthalmic Lens with Refractive Index 1.6

[0117] Formulae 1-12 according to the invention and Comparative Formulae Comp. 1-5 comprising the following ingredients were prepared. The values expressed in the tables below are weight percentages based on the total weight of the composition.

TABLE-US-00004 Formula 1 2 3 4 5 6 7 8 9 10 11 12 ISO1 49.89 50.49 49.79 49.69 49.79 49.92 49.79 49.90 49.86 49.93 49.82 49.93 THIO1 23.56 23.85 23.51 23.47 23.51 23.58 23.51 23.57 23.55 23.58 23.53 23.58 THIO2 25.14 25.44 25.09 25.04 25.09 25.16 25.09 25.14 25.13 25.16 25.11 25.16 DMC 0.039 0.040 0.039 0.039 0.039 0.039 0.039 0.039 0.039 0.039 0.039 0.039 Seesorb ® 709 1.184 1.184 1.184 1.184 1.184 1.184 1.184 1.184 1.184 1.181 1.184 Seesorb ® 703 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 0.012 Zelec ® UN 0.069 0.070 0.069 0.069 0.069 0.069 0.069 0.069 0.069 0.069 0.069 0.079 Oxazolone (IVa) 0.099 0.100 0.295 0.491 — — — — — — — — Oxazolone (IVb) — — — — 0.295 0.025 — — — — — — Oxazolone (IVc) — — — — — — 0.295 — — — — — Oxazolone (IVd) — — — — — — — 0.074 — — — — Oxazolone (IVg) — — — — — — — — 0.142 — — — Oxazolone (IVh) — — — — — — — — — 0.006 — — Oxazolone (IVf) — — — — — — — — — — 0.246 — Oxazolone (IVj) — — — — — — — — — — — 0.0069 Total 100 100 100 100 100 100 100 100 100 100 100 100

TABLE-US-00005 Formula Comp. 1 Comp. 2 Comp. 3 Comp. 4 Comp. 5 ISO1 49.940 50.045 50.278 49.313 49.554 THIO1 23.588 23.638 23.748 23.292 23.406 THIO2 25.167 25.220 25.268 24.851 24.973 DMC 0.039 0.040 0.040 0.039 0.039 Seesorb ® 709 1.184 — — — — Seesorb ® 703 0.012 — — — 1.959 Zelec ® UN 0.069 0.069 0.070 0.068 0.069 Eversorb ® 109 — 0.989 — — — Sunsorb ® 327 — — 0.596 — — Tinuvin ® 928 — — — 2.436 — Total 100 100 100 100 100

[0118] The compositions were prepared according to the following steps: [0119] 1. oxazolone and/or UV absorbers were dissolved in ISO1 or THIO2; [0120] 2. DMC and Zelec® UN were mixed with ISO1 in a Duran bottle (100 ml) at room temperature (20-25° C.) under vacuum until homogeneous; [0121] 3. the mixture was cooled down to 20° C. before vacuum was released and replaced with N.sub.2; [0122] 4. THIO 1 and THIO2 were added in the mixture; [0123] 5. the mixture was stirred under vacuum at 20° C. until homogeneous.

Example 5: Preparation of Ophthalmic Lens with Refractive Index 1.6

[0124] Formulae 1-12 according to the invention and Comparative Formulae Comp. 1-5 obtained according to Example 4 were polymerized to obtain an ophthalmic lens with the following steps: [0125] 1. a 71 mm diameter glass bi-plano mold was filled with the composition using a syringe; [0126] 2. polymerization was carried out in a regulated electronic oven in which the temperature was gradually increased from 15° C. to 130° C. in 16 hours then kept constant at 130° C. for 4 hours; [0127] 3. the mold was then disassembled and the resulting lens had a 2 mm thickness in its center.

[0128] The characteristics of the ophthalmic lens are given in the following tables:

TABLE-US-00006 light cut TvD65 TmB1 TmB2 Formula (nm) (%) (%) (%)  1 408 89.72 83.08 89.25  2 407 89.37 83.56 88.86  3 412 89.30 76.31 88.86  4 415 89.33 71.41 88.81  5 417 89.11 63.36 88.54  6 406 89.64 83.74 89.26  7 469 85.89 0.01 38.81  8 407 89.13 83.47 88.65  9 407 89.09 83.66 88.64 10 408 89.26 37.67 88.95 11 406 89.10 82.95 88.62 12 493 66.78 10.36 0.84 Comp. 1 396 89.62 88.06 89.34 Comp. 2 407 89.34 80.80 89.00 Comp. 3 408 89.49 79.50 89.21 Comp. 4 408 90.35 82.32 90.07 Comp. 5 418 21.22 11.40 17.80

TABLE-US-00007 Formula YI L* a* b* C* h* 1 5.33 95.82 −2.24 4.65 5.16 115.70 2 5.06 95.68 −2.08 4.35 4.83 115.60 3 7.83 95.62 −3.41 6.87 7.67 116.40 4 9.70 95.62 −4.10 8.35 9.30 116.15 5 12.66 95.50 −5.13 10.58 11.76 115.90 6 4.85 95.79 −2.09 4.27 4.75 116.10 7 89.64 92.93 −19.48 97.89 99.81 101.30 8 5.02 95.58 −2.07 4.33 4.80 115.50 9 4.86 95.56 −1.98 4.17 4.62 115.40 10 25.27 95.47 −9.23 20.06 22.08 114.70 11 5.04 95.57 −1.99 4.22 4.67 115.25 12 121.24 82.90 19.37 91.25 93.29 78.00 Comp. 1 2.16 95.82 −0.69 1.56 1.70 113.75 Comp. 2 5.83 95.66 −2.56 5.16 5.76 116.40 Comp. 3 6.33 95.72 −2.81 5.60 6.26 116.65 Comp. 4 5.55 96.08 −2.50 4.97 5.57 116.63 Comp. 5 37.60 52.81 −0.03 14.40 14.40 90.13

[0129] According to above results, at the same light cut level either at around 407 or 418 nm, lenses comprising an oxazolone according to the invention displayed superior properties, i.e. lower YI, b* and c*, relative to those of lens comprising only a benzotriazole UV absorber. For instance, formulae 1, 2, 8 and 9 have a similar light Cut with Comp. formulae 2, 3 and 4, but their YI is lower than 5.3, sometimes around 5, as compared to YI higher than 5.5, sometimes around 6. Comparison of formulae 4 and 5 with comparative formula 5 demonstrates the same difference: similar light Cut but with lower YI.

[0130] Further, since oxazolone has a high absorption coefficient, the required amount of oxazolone to reach this light cut was much less than the amount needed of a conventional benzotriazole UV absorber.

[0131] The light cut, yellow index and transmittance (TvD65) measured immediately after manufacture (t=0) and after accelerated ageing in Q-Sun cell (t=80) for the lens obtained with Formula 1, 2, and 5 to 10 are given in the table below:

TABLE-US-00008 light light Δlight cut cut cut ΔYI TvD65 TvD65 ΔTvD65 t = 0 t = 80 t = 80 YI YI t = 80 t = 0 t = 80 t = 80 Formula (nm) (nm) (%) t = 0 t = 80 (%) (%) (%) (%) 1 408 406 −0.49 5.33 6.23 16.89 89.72 88.93 −0.88 2 407 406 −0.25 5.06 9.81 93.87 89.37 87.02 −2.63 5 417 415 −0.48 12.66 15.69 23.93 89.11 86.71 −2.69 6 406 399 −1.72 4.85 4.29 −11.55 89.64 89.28 −0.40 7 469 465 −0.85 89.64 85.32 −4.82 85.89 86.31 0.49 8 407 405 −0.49 5.02 5.57 10.96 89.13 88.82 −0.35 9 407 403 −0.98 4.86 10.57 117.49 89.09 86.12 −3.33 10 408 402 −1.47 25.27 21.26 −15.87 89.26 88.37 −1.00

[0132] The light cut and the transmittance of the lens are relatively stable upon aging. The lens obtained with Formula 1 comprising a mixture of oxazolone and benzotriazole UV-absorbers exhibits significantly less increase in Yellow Index compared to that of the lens obtained with Formula 2 comprising an oxazolone only. The lens obtained with Formula 6 comprising a reduced amount of oxazolone exhibits a lower light cut and significantly less increase in Yellow Index compared to that of the lens obtained with Formula 5 comprising more than 10 times more oxazolone.

[0133] Formulae 7 and 12 yield an ophthalmic lens which is actually an efficient filter in blue area, i.e. a very coloured yellow lens.

Example 6: Preparation of Compositions to Obtain an Ophthalmic Lens with Refractive Index 1.67

[0134] Formulae 20-27 according to the invention and Comparative Formula Comp. 6 comprising the following ingredients were prepared. The values expressed in the table below are weight percentages based on the total weight of the composition.

TABLE-US-00009 Formula 20 21 22 23 24 25 26 27 Comp. 6 ISO2 52.03 52.01 51.38 51.36 51.00 51.36 51.37 51.34 51.06 THIO2 47.87 47.85 47.27 47.26 46.91 47.23 47.27 47.24 46.98 DMC (ppm) 0.01 0.01 0.01 0.010 0.010 0.010 0.010 0.010 0.01 Zelec(ppm) 0.08 0.08 0.10 0.099 0.078 0.079 0.079 0.079 0.08 Seesorb ® 709 − − − − − − − − 1.67 Seesorb ® 703 − − − − − − − − 0.20 Oxazolone 0.01 0. 05 0.01 − − − − − − (IVb) Oxazolone − − − 0.030 0.029 0.030 − − − (IVa) Oxazolone − − − − − − 0.030 − − (IVd) Oxazolone − − − − − − − 0.099 − (IVf) Seesorb ® 701 − − 1.23 1.233 1.959 1.233 1.233 1.232 − Tinuvin ® 144 − − − − − 0.049 − − − Total 100 100 100 100 100 100 100 100 100

[0135] The compositions were prepared according to the following steps: [0136] 1. oxazolone and/or UV absorbers were dissolved in ISO2 or THIO2; [0137] 2. DMC and Zelec® UN were mixed with ISO2 in a Duran bottle (100 ml) at room temperature (20-25° C.) under vacuum until homogeneous; [0138] 3. the mixture was cooled down to 20° C. before vacuum was released and replaced with N.sub.2; [0139] 4. THIO2 was added in the mixture; [0140] 5. the mixture was stirred under vacuum at 20° C. until homogeneous.

Example 7: Preparation of Ophthalmic Lens with Refractive Index 1.67

[0141] Formulae 20-27 according to the invention and Comparative Formula Comp. 6 obtained according to Example 6 were polymerized to obtain an ophthalmic lens with the following steps: [0142] 1. a 71 mm diameter glass bi-plano mold was filled with the composition using a syringe; [0143] 2. polymerization was carried out in a regulated electronic oven in which the temperature was gradually increased from 20° C. to 120° C. in 14.5 hours then kept constant at 120° C. for 3 hours; [0144] 3. the mold was then disassembled and the resulting lens had a 2 mm thickness in its center.

[0145] The characteristics of the ophthalmic lens are given in the following tables:

TABLE-US-00010 light cut TvD65 TmB1 TmB2 Formula (nm) (%) (%) (%) 20 406 88.05 81.00 87.77 21 415 88.05 68.56 87.74 22 407 87.96 80.7 87.8 23 408 88.19 80.55 87.36 24 408 88.14 79.74 87.35 25 407 87.85 81.23 87.29 26 408 87.39 80.49 86.96 27 408 87.26 78.65 86.66 Comp. 6 408 87.79 76.98 87.71

TABLE-US-00011 Formula YI L* a* b* C* h* 20 5.30 95.12 −2.24 4.64 5.16 115.80 21 9.53 95.08 −4.06 8.23 9.18 116 22 5.36 95.08 −2.27 4.69 5.21 116 23 5.03 95.18 −2.12 4.40 4.89 115.80 24 5.58 95.15 −2.38 4.89 5.44 116.00 25 5.01 95.04 −2.12 4.37 4.86 115.83 26 5.47 94.84 −2.31 4.77 5.30 115.80 27 6.43 94.78 −2.53 5.39 5.95 115.15 Comp. 6 6.98 94.99 −2.77 5.89 6.51 116

[0146] According to above results, at the same light cut level either at around 407, lenses comprising an oxazolone according to the invention displayed superior properties, i.e. lower YI, b* and c*, relative to those of lens comprising only a benzotriazole UV absorber. For instance, formulae 22 to 26 have a similar light cut to that of formula Comp. 6, but their YI is lower than 5.3, sometimes around 5.6, as compared to a higher YI around 7.

[0147] Further, since oxazolone has a high absorption coefficient, the required amount of oxazolone to reach this light cut was much less than the amount needed of a conventional benzotriazole UV absorber.

[0148] The light cut, yellow index and transmittance (TvD65) measured immediately after manufacture (t=0) and after accelerated ageing in Q-Sun cell (t=80) for the lens obtained with Formula 20-26 and Comp. 6 are given in the table below:

TABLE-US-00012 light light Δlight cut cut cut ΔYI TvD65 TvD65 ΔTvD65 t = 0 t = 80 t = 80 YI YI t = 80 t = 0 t = 80 t = 80 Formula (nm) (nm) (%) t = 0 t = 80 (%) (%) (%) (%) 20 406 301 −25.86 5.30 7.79 46.98 88.05 85.44 −2.96 21 415 380 −8.43 9.53 18.42 93.28 88.05 81.75 −7.16 22 407 399 −1.97 5.36 3.62 −32.46 87.96 87.57 −0.44 23 408 402 −1.47 5.03 5.10 1.39 88.19 87.51 −0.77 24 408 404 −1.06 5.58 5.25 −5.85 88.14 87.28 −0.97 25 407 403 −1.05 5.01 5.59 11.62 87.85 87.16 −0.78 26 408 401 −1.72 5.47 4.59 −16.09 87.39 86.35 −1.19 Comp. 6 408 408 0.00 6.98 7.01 0.43 87.79 87.73 −0.07

[0149] The lens obtained with Formula 22 comprising a mixture of oxazolone and benzotriazole UV-absorber exhibits a significant decrease in Yellow Index upon aging compared to the lens obtained with Formula comprising an oxazolone only which exhibits an increase of Yellow Index upon aging.

[0150] Addition of a light stabilizer in Formula 25 lowers the degradation of light cut during ageing in Q-Sun cell: light cut is reduced of 4 nm, whereas the same composition, but without light stabilizer (Formula 23) shows a light cut reduction of 6 nm. Comparison with Formula 24 shows that a very low amount of light stabilizer (0.05%) has a similar effect than an increase of UV absorber (from 1.23% to 1.95%). Finally, combination of oxazolone with UV absorber and light stabilizer provides a very efficient lens with low amounts of additives.

Example 8: Preparation of Ophthalmic Lens with Refractive Index 1.50

[0151] The ophthalmic lens prepared in example 8 comprises a plastic base having a refractive index of 1.50 (ORMA® from Essilor, a copolymer based on diethylene glycol bis(allyl carbonate)), using imbibition method.

[0152] A solution containing 0.8 g of oxazolone (IVa) and 0.2 g of Sodium dodecylbenzenesulfonate is prepared in soft water (qsp 100 g). The solution is heated at 95° C.

[0153] The plastic base is soaked in said solution. The imbibition time is 10-15 minutes, depending on the desired light cut. The higher the desired light cut, the longer the imbibition time.

[0154] Then, the ophthalmic lens is withdrawn from the bath, laid on a tray and placed in an oven for 1 hour at 100° C.±3° C.

[0155] Light cuts ranging from 390 nm to 400 nm were obtained.