BE1021377B1 - POLYMERIZABLE COMPOSITION FOR MANUFACTURING IMPLANTABLE LENSES AND METHOD THEREOF - Google Patents

Abstract

The present invention relates to a polymerizable composition for manufacturing implantable lenses comprising at least a first compound comprising at least two hydroxyl groups and at least a second compound comprising at least two isocyanate groups, the molar ratio between the isocyanate groups and the hydroxyl groups of said composition before polymerization being between 0.93 and 1.3, and method using this composition to manufacture these lenses.

Description

Polymerizable composition for making implantable lenses and method thereof

The present invention relates to a polymerizable composition for making implantable lenses.

Implantable lenses, of which intraocular ophthalmic lenses are one example, must meet stringent requirements in terms of optical performance, biomechanical properties and biological properties. Indeed, such lenses are intended for replacing the opacified human lens (cataract) with an intraocular lens inserted via; a corneo-scleral micro-incision (2 mm). This type of surgery, consisting of a removal of the lens and the placement of an intraocular lens, is now widely recognized and proven since it is a technique that reduces the risk of astigmatism related to such intervention and that recovery of patients is faster.

A major constraint however remains the fact that the intraocular lens must necessarily be compatible both mechanically and biologically with the particular environment of the eye. Indeed, for the success of this type of surgical procedure, the intraocular lens must necessarily be flexible, deformable and elastic not only to allow its insertion into the micro-incision but also to effectively replace the human lens by covering its shape. once set up. Such intraocular lens properties are essentially related to the nature of the polymer used to make them. '

At present, four main groups of polymers are used for the manufacture of intraocular lenses: polymethyl methacrylates (PMMA), silicones, polymethacrylic hydrophilic copolymers and polymethacrylic hydrophobic copolymers. For example, the documents US5833890 and US5725576 propose polymeric compositions for elastic intraocular lenses, these compositions comprising in admixture an oligourethane methacrylate, a methacrylate of a 2,2-phenylacetone phenol oligocarbonate and a methacrylate of an oligocarbonate of 2, 4-diterbutylorthoquinone.

These two documents also teach a method of manufacturing intraocular lenses from the aforementioned mixtures. This method relies on the injection of the mixture obtained into a mold arranged to confer the desired shape on the intraocular lens. Once the polymer mixture is placed in the mold, the polymerization is provided by irradiation with a particular radiation at 320-380 nm.

Unfortunately, even if such suspected intraocular lenses meet the biomechanical requirements for proper implantation through the pupillary port, it turns out that these lenses,. manufactured from such radiation polymerized materials, do not allow to incorporate anti-UV agents and / or anti-blue light while UV and blue light correspond to wavelengths toxic to the retina. Indeed, UV blocking agents and blue light blocking agents interact with the applied radiation to effect polymerization. As a result, this radiation is modified, especially in terms of intensity, which has the effect of making the polymerization incomplete, too slow or nonexistent. The object of the invention is to overcome the drawbacks of the state of the art by providing a polymerizable composition capable of allowing the incorporation of ultraviolet blocking agents and / or blue light blocking agents, while by making it possible to carry out an optimal polymerization, that is to say a polymerization giving rise to a polymer that responds to the mechanical and biological constraints related to the environment of the eye. As mentioned above, it is indeed necessary that the lenses obtained from the polymer are flexible, deformable and elastic to be able to effectively replace the lens.

To solve these problems, there is provided according to the invention, a polymerizable composition for producing implantable lenses comprising at least a first compound comprising at least two hydroxyl groups and at least one second compound comprising at least two isocyanate groups, the molar ratio between the isocyanate groups and the hydroxyl groups of said composition before polymerization being between 0.93 and 1.3 and the composition further comprising at least one chromophore agent at least partially filtering ultraviolet-domain wavelengths less than 400 nm or at least one Chromophore agent at least partially filtering wavelengths of the blue light range between 400 and 500 nm or these two agents simultaneously.

In the context of the present invention, it has been shown that a polymerizable composition of this type can be thermally polymerized, which makes it possible to achieve optimal polymerization even in the presence of chromophoric agents (anti-UV and anti blue light), in contrast to current techniques based on irradiation of the polymerizable composition.

The polymerizable composition according to the invention makes it possible to obtain an elastomeric polyurethane-type polymer by thermal polymerization. For the purposes of the present invention, the term "elastomer" is intended to mean that the polymer obtained has elastic properties enabling it to recover its initial shape following the application of a deformation force.

A polyurethane results from a polyaddition reaction between a compound carrying at least two mobile hydrogens of alcohol type HO-R-OH and a compound with at least two isocyanate functions -N = C = O to form, in a first step, a prepolymer. A second step consists in the association of the prepolymer chains with each other. This step is carried out via a chain extender for obtaining polyurethane chains, the chain extenders reacting with the isocyanate to give rise to bonds that connect the segments together.

The isocyanate functions are particularly reactive because of the presence of both unsaturations and therefore strongly react with all the mobile hydrogen compounds. More particularly, when mixing a compound comprising at least two mobile hydrogens with a compound comprising at least two isocyanate groups, the hydrogen atoms of the compound bearing at least two mobile hydrogens are fixed on the nitrogen atoms of the isocyanate groups. while the residues of the compound comprising at least two mobile hydrogens bind to the carbons of the carbonyl (CO) groups, which gives rise to the formation of urethane functions RCO-ONHR '.

Polyols are the source of the flexible segments of the polyurethane chain while isocyanates are the source of the rigid segments of the polymer. Depending on the desired final performance for polyurethane type polymer, it is possible to play on the molar ratio between the isocyanate groups and the hydroxyl groups before polymerization during the formation of the prepolymer. It is indeed possible to move away from the stoichiometric proportion of these two isocyanate and hydroxyl reactive functions. In this case, it is referred to as over-indexing, meaning that the isocyanate groups are in excess and the hydroxyl groups are in defects, a molar ratio [N = C = O] / [OH] greater than unity giving rise to a crosslinked polymer. On the other hand, when this same molar ratio is less than unity, it is called under-indexing (isocyanate groups in default) and the final product obtained is not completely polymerized and crosslinked, which gives rise to soft and sticky product.

In the context of the present invention, it has been determined that a molar ratio between the isocyanate groups and the hydroxyl groups of between 0.93 and 1.3 before polymerization makes it possible to obtain an elastomer-type polyurethane polymer which is suitable for the manufacture of implantable lenses such as intraocular ophthalmic lenses, which can incorporate chromophoric agents which do not affect the thermally formed polymerization in any way.

Indeed, if the molar ratio between the isocyanate groups and the hydroxyl groups before polymerization is too low and less than 0 ', 93, the polymerization stops too quickly once the isocyanate groups in default have been consumed. This results in a partial polymerization and a polymer not suitable for the manufacture of implantable lenses, said polymer obtained being too soft and sticky. If the same molar ratio is, on the other hand, too high and greater than 1.3, the excess of isocyanate groups in the reaction mixture leads to the production of a polymer which is crosslinked but which is not, however, suitable for manufacture. of implantable lenses, this polymer does not meet the mechanical properties required when the molar ratio [N = C = O] / [OH] is greater than 1.3.

In the context of the present invention, it has been determined that a molar ratio [N = C = O] / [OH] of between 0.93 and 1 makes it possible to obtain a thermoplastic linear polymer while a molar ratio at less than 1 and at most 1.3 makes it possible to obtain a non-thermoplastic crosslinked polymer, both types of polymers having such molar ratios being both suitable for the manufacture of implantable lenses according to the invention.

Moreover, it has been shown that the lenses obtained from the composition according to the invention have all the characteristics and the biomechanical and biological properties required for optimal replacement of the human lens. In fact, the intraocular lenses thus obtained are flexible and perfectly cover their initial shape.

In the context of the present invention, it has also been shown that these intraocular lenses have excellent biocompatibility, they cause only weak inflammatory reactions and they have adequate strength and elasticity properties. It has also been shown that any type of intraocular lens, haptic or optical, refractive monofocal, refractive or multifocal diffractive or toric can be made from said thermally polymerizable polyurethane elastomer polymer.

As a first compound, it is possible to envisage according to the invention both "monomers", "oligomers" or "polymers" containing at least two hydroxyl groups, these compounds being characterized respectively by a chain consisting of a single unit, a small number of reasons less than 100 and a large number of reasons greater than 100. This first compound forms the soft segment of the polymer, giving the latter its flexibility.

In particular, according to the invention, it is possible to envisage as a first compound a compound chosen from the group consisting of polyethers, ... polyesters, and the like. polycarbonate polyols, polycaprolactone polyols, polybutadiene polyols, sulfurized polyols, fluorinated polyols, and mixtures thereof.

More particularly, according to the invention, the first compound may be chosen from the group consisting of polytetrahydrofuran, polypropylene glycol, polyethylene glycol, poly- (1,6-hexanediol-earbonate) -glycol, poly (diethylene glycol) adipate) -diol, poly (hexamethylene-2,2-dimethylpropylene glycol adipate) diol and mixtures thereof.

Of course, those skilled in the art will be able to determine other first compounds suitable for the present invention. According to the invention, the second compound may be a compound selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3,3'-diisocyanate, and the like. 4,4'-dimethyl-biphenyl and mixtures thereof. This second compound forms the rigid segment of the polymer, giving the latter its physical and mechanical stability.

Of course, one skilled in the art will be able to determine other second compounds suitable for the present invention.

In particular, according to the invention, said at least one chromophore agent at least partially filtering wavelengths of the ultraviolet range of less than 400 nm is selected from the group consisting of benzophenones, anthracenes, benzatriazole derivatives and of their mixtures.

More particularly, according to the invention, said at least one chromophore agent at least partially filtering wavelengths of the ultraviolet range below 400 nm is chosen from the group consisting of 2,4-dihydroxybenzophenone-vinylanthracene, 2 - (20-hydroxy-30-methallyl-50-methylphenyl) -benzotriazole, 2- (5-chloro-2H-benzotriazol-2-yl) -6 - ((1,1-dimethylethyl) -4-methyl) - phenol, 2- [20-hydroxy-50- (b-methacryloyloxyethoxy) -30-t-butylphenyl] -5-methyl-2H-benzotriazole, 2- [20-hydroxy-50- (g-methacryloyloxypropoxy) -30 t-butylphenyl] -5-methyl-2H-benzotriazole and mixtures thereof.

It is understood that one skilled in the art will be able to determine other chromophoric agents at least partially filtering wavelengths of the ultraviolet range below 400 nm suitable for the present invention.

Preferably, according to the invention, the composition comprises from 0.001 to 1% by weight, preferably from 0.01 to 0.5% by weight, of said chromophore agent at least partially filtering wavelengths of the ultraviolet range. less than 400 nm.

In particular, according to the invention, said at least one chromophore agent at least partially filtering wavelengths of the blue light domain between 400 and 500 nm is selected from the group consisting of N-2- [3- ( 20-methylphenylazo) -4-hydroxyphenyl-ethyl-methacrylamide, methyl-2-hydroxy-5 - ((4-hydroxyphenyl) azo) -benzoate, N, N-bis- (2-methacryloyl-ethyl) - ( 4-phenylazo) aniline and mixtures thereof.

Preferably, according to the invention, the composition comprises from 0.001 to 1% by weight, preferably from 0.01 to 0.5% by weight, of said chromophore agent at least partially filtering the wavelengths of the field of blue light. between 400 and 500 nm.

Optionally, the chromophore agent at least partially filtering the wavelengths of the blue light domain and the chromophore agent filtering at least partially the wavelengths of the ultraviolet range may contain at least two hydroxyl groups and may then serve at least partially first compound according to the invention.

Advantageously, according to the invention, the composition further comprises a chain extender chosen from the group consisting of diols, amino-alcohols, diamines and their mixtures.

More particularly, said chain extender is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, butanediol, hexanediol, ethanolamine, and mixtures thereof. The chain extender makes it possible to adjust the length of the rigid segments and thus to adjust the size of the crosslinked segments of the polymer.

Preferably, according to the invention, the molar ratio between the isocyanate groups and the hydroxyl groups of the composition before polymerization is between 0.96 and 1.1. Other embodiments of the polymerizable composition according to the invention are indicated in the appended claims. The subject of the invention is also a method for manufacturing implantable lenses starting from a polymerizable composition based on at least one first compound comprising at least two hydroxyl groups and at least one second compound comprising at least two isocyanate groups. this method comprising: a step of mixing said at least one first compound with said at least one second compound so as to obtain a prepolymer having a molar ratio between isocyanate groups and hydroxyl groups of between 0.93 and 1.3; a step of adding to the prepolymer of a chain extender agent to obtain a mixture of prepolymer and chain extender, - a step of thermally polymerizing said prepolymer and chain extender mixture with formation of a polymer, and a step of forming said implantable lenses from said polymer obtained.

Such a manufacturing process is particularly advantageous since the polymerization is carried out thermally by heating. Such thermal polymerization is not affected by the presence of anti-UV chromophoric agents and / or filtering wavelengths of blue light, which is not the case for irradiation polymerizations described in the state. of the technique. Indeed, generally and as described in US5833890 and US5725576, the polymerization is provided by the application of a particular radiation (320 to 380 nm). However, as mentioned above, this particular radiation can interact with said anti-UV agents and filter wavelengths of blue light, which has the effect of considerably reducing its intensity and making the polymerization incomplete, too slow, nonexistent. This then leads to obtaining a polymer from which intraocular lenses having the biomechanical and biological characteristics required for correct placement in the micro-incision practiced can not be reached. The present invention therefore excludes any radiation polymerization of the prepolymer.

Preferably, according to the invention, said polymerization step forms a polymer having a water absorption rate of less than 5%. If the polymer absorbs too much water (water absorption rate greater than 5%), it can then be considered as a hydrogel, that is to say a water-insoluble polymer capable of to form a kind of gel having a high absorbency. However, the hydrogels have limited capsular biocompatibility in the eye and promotes cell adhesion on their surface and thus the formation of posterior secondary opacification. However, a polymer for the manufacture of implantable lenses, more particularly for the manufacture of intraocular lenses, must not present this problem of opacification. The manufacture of a polyurethane characterized by a water absorption rate of less than 5% according to the invention does not have this problem related to cell adhesion.

Advantageously, the method according to the invention comprises a step of adding, before said polymerization step, at least one chromophore agent at least partially filtering wavelengths of the ultraviolet range of less than 400 nm to the mixture of prepolymer and agent, chain extender, and / or at least one chromophore agent at least partially filtering blue-light wavelengths between 400 and 500 nm to the prepolymer and extender mixture of chain.

Preferably, said polymerization step is carried out by heating at a temperature of between 50 and 150 ° C, preferably between 80 and 110 ° C.

Advantageously, said step of forming the implantable lens is preceded by a step of melting said polymer formed followed by injection into a mold, in particular when the molar ratio between the isocyanate groups and the hydroxyl groups of said prepolymer is less than 1.

Just as advantageously, said step of forming the implantable lens is carried out directly in a mold, in particular when the molar ratio between the isocyanate groups and the hydroxyl groups of said prepolymer is greater than or equal to 1.

Preferably, the method according to the invention further comprises at least one additional step of sterilizing said implantable lenses.

Advantageously, said additional sterilization step is carried out by steam sterilization. Such sterilization has the advantage of being performed in wet conditions, that is to say in conditions close to those of the eye. Thus, during placement of said intraocular lens in said micro-incision, said intraocular lens does not change properties due to a drastic change in environmental conditions (humidity). Furthermore, it has been shown, in the context of the present invention, that such sterilization makes it possible to obtain non-scintillating intraocular lenses ("no glistening"), that is to say without formation of micro-vacuoles. filled with water or water vapor causing opacification of said intraocular lenses, which can then be packaged in an aqueous phase. This steam sterilization is directly related to the property of the polymer according to which it has a water absorption rate of less than 5%. Indeed, for such a type of sterilization, the presence of water in the polymer must be controlled to minimize the mechanical stress caused in the polymer by the simultaneous application of heat, steam and pressure during sterilization This can lead to undesirable effects such as the formation of microvacuoles containing water vapor if the polymer absorbs too much water. This results in opacification of the implantable lens sterilized in this way if the polymer forming it has a water absorption rate greater than 5%. Other embodiments of the method of manufacturing implantable lenses according to the invention are indicated in the appended claims. The subject of the invention is also implantable lenses obtained according to the process according to the invention. The invention also relates to the use of a polymerizable composition as described above for the manufacture of implantable lenses. The invention also relates to a polyurethane for the production of implantable lenses from a composition according to the invention.

The single appended figure is a graph for comparing different types of lenses in terms of transmittance according to wavelengths. Other details and particularities of the invention will become apparent from the examples given below without being limiting.

Examples

Example 1 Manufacture of a Polyurethane Intraocular Lens Comprising an Anti-UV Agent and a Blue Light Wavelength Filtering Agent (TPU 1)

A first compound, polytetrahydrofuran (pTHF) is combined with a second monomer, toluene diisocyanate (TDI) in a molar ratio of 1 mol eq of pTHF per 2 mol eq of TDI to make a first mixture and obtain a prepolymer. This first mixture is mixed for 2 hours at a temperature of 80 ° C using a mechanical stirrer. Then, 0.005 mole eq of 2,4-dihydroxybenzophenone (DHBP) used as anti-UV agent and 0.0025 mole eq of 4-phenylazophenol (PAP) used as a filtering agent for the wavelengths of blue light (said anti-UV agent). UV and filtering agent wavelengths of blue light being in solution in tetrahydrofuran (THF) at a level of 10% by weight) are added to the first mixture to obtain a second mixture. This is then stirred for 5 minutes before the addition of 0.9925 mol eq of ethylene glycol (EG) used as a chain extender to obtain a third mixture which is stirred for 5 minutes and subjected to a temperature rise up to at 90 ° C. After 1 hour of reaction at a temperature of 90 ° C, the polyurethane mixture is poured into a mold where the polymerization reaction is completed at a temperature of 110 ° C under vacuum for 23 hours. After this polymerization step, the mold is cooled to a temperature of about 5 to 30 ° C before opening to extract the intraocular lens formed.

Example 2 Manufacture of a Polyurethane Intraocular Lens Comprising an Anti-UV Agent (TPU 2)

The manufacture of a polyurethane intraocular lens comprising an anti-UV agent is based on the same steps performed under the same conditions as those mentioned in Example 1, with the difference that there is no addition here of 4 phenylazophenol as a filtering agent for the wavelengths of blue light.

Example 3 Manufacture of an Intraocular Polyurethane Lens (TPU3)

The manufacture of a polyurethane intraocular lens comprising neither an anti-UV agent nor a filtering agent for the wavelengths of blue light is based on the same steps performed under the same conditions as those mentioned in Examples 1 and 2 in FIG. difference that there is no addition here of 4-phenylazophenol nor 2,4-dihydroxybenzophenone.

Example 4: comparative tests

In order to verify and compare the properties of the implantable lenses obtained according to the present invention (TPU 1, TPU 2 and TPU 3), the implantable lenses manufactured according to the above three examples were compared to reference lenses currently used for the manufacture of intraocular lenses based on polymethacrylate (Ref 1 and Ref 2).

The table below shows the general characteristics of the different implanted lenses compared.

(a) Benzol 25Y (Benz Research and Development, USA) (b) Benzol 25 (Benz Research and Development, USA) 1. Characteristics of the nanostructuration of elastomeric polymers · To evaluate the characteristics of the nanostructuration of elastomeric polymers obtained according to the invention and to compare them with those of polymers based on polymethacrylate, the technique of transmission electron microscopy has been applied (Phillips CM 100 TEM, equipped with a Gatan 673 CCD camera connected to a computer with the Kontron program KS 10).

It has been shown that the elastomeric polymers TPU 1, TPU 2 and TPU 3 consist of an alternation of soft and hard domains, the hard domains resulting from crystallization by inter and intra-molecular hydrogen bond formation while the Soft domains remain in their amorphous state. These characteristics confer good mechanical strength, correct shape memory and adequate flexibility to the polymers obtained. In order to avoid any problem of opacification due to phase separation, the sizes of the hard and soft domains must be controlled and preferably not exceed 100 nm. The images obtained according to the above-mentioned microscopic technique have demonstrated the formation of polyurethane aromatic domains having a size of less than 2 nm alternating with domains of a similar size of polytetrahydrofuran (pTHF). On the other hand, such nano-structuring is not observed for polymers Ref. 1 and Ref. 2.

However, the minute sizes of the domains constituting the polymers obtained according to the invention (TPU 1, TPU 2 and TPU 3) pose no problem and are perfectly suitable for the manufacture of implantable lenses, such particle sizes having no impact on the light transmission properties in the visible range (see point 3 below). 2. Chemical Properties of the Polymers: Absence of the OCN- • Groups In order to determine whether -N = C = O groups are present or not in the polymers obtained according to the invention, the total-attenuated infrared spectroscopy technique has Fourier (ATR-IR) has been implemented (BRUKER's Alpha-Eco FT-IR equipped with a ZnSe crystal). The spectra were determined in the range of 500 to 300 cm -1 at a resolution of 4 cm -1 and treated with the Opus program.

The presence of such groups in the final material of the molded and polymerized lens should be avoided as they can cause severe post-surgical complications (toxicity, inflammation, biological incompatibility). The spectra obtained made it possible to demonstrate the absence of a band at 2200 cm -1 typical of the groups -N = C = O for the three polymers obtained according to the invention.

3. Optical properties of polymers: UV blocking

The UV spectra relating to each of the polymers obtained according to the invention and to the reference polymers were determined by working from polymer disc (1 mm thick and 16 mm in diameter in the dry state) by spectrophotometry (GENESYS ™ 6 from Thermo Scientific) in a wavelength range of 200 to 900 nm (with a resolution of 2 nm). The spectra obtained were processed using the Visionlite software.

The attached FIG. 1 shows that the TPU 3 polymer comprising neither an anti-UV agent nor a filtering agent for the wavelengths of the blue light according to the invention totally blocks the wavelengths up to 300 nm and at least partially the wavelengths. wavelengths between 300 and 320 nm, which indicates that the addition of an anti-UV agent is not necessarily required.

The TPU 2 polymer comprising only an anti-UV agent makes it possible to block all wavelengths up to 355 nm, which is comparable to the reference polymer Ref. 1.

The simultaneous presence of the filtering agent for the wavelengths of blue light (PAP) and the anti-UV agent, which is the case for the TPU 1 polymer according to the invention, results in the filtration of 70% blue light at 430 nm, which is comparable to the reference polymer Ref.2.

It has also been demonstrated that the transmission of light in the wavelength range visible between 550 and 750 nm remains sufficiently high with more than 80% of the transmitted light for all the polymers according to the invention and the reference polymers. . This tends to demonstrate that implantable lenses made from polyurethane are adequate and do not disturb the patient's vision. 4, Measurement of the refractive index The refractive index relating to each of the polymers obtained according to the invention and to the reference polymers was determined by working from the polymer disc (1 mm thick and 16 mm thick). diameter in the dry state) by refractometry (AR 12 from Schmidt & Haensch GmbH & Co). The measurements were carried out at 21 ° C. and at a wavelength of 589 nm. The table below mentions the values obtained.

A refractive index of 1.511 was determined for the three polymers obtained according to the invention while a refractive index of 1.46 and lower was determined for the reference polymers, indicating that the implantable lenses manufactured from polyurethane are adequate and may even allow for the fabrication of thinner implantable lenses, which would further facilitate their use for insertion into the micro-incision 5. Optical Bench Analysis

The optical properties (dioptre and contrast sensitivity) of implantable lenses obtained according to the invention were analyzed using an optical bench (Nimo® TR0815 from Lambda-X). This test was performed in physiological saline (0.9% NaCl) in a quartz tank at 18 ° C at a wavelength of 546 nm and with a 3 mm aperture simulating pupil size for a normal daily vision. The modulation transfer function (MTF) was determined for the particular frequency of 100 Ip / mm (resolution) in the model of the eye.

The optical bench analyzes made it possible to conclude that the implantable lenses obtained from the polymerizable composition according to the invention have optical properties comparable to those of the reference lenses (Ref.1 and Ref.2).

It is understood that the present invention is in no way limited to the embodiments described above and that many modifications can be made without departing from the scope of the appended claims.

Claims (22)

Polymerizable composition for producing implantable lenses comprising at least a first compound comprising at least two hydroxyl groups and at least one second compound comprising at least two isocyanate groups, characterized in that the molar ratio between the isocyanate groups and the hydroxyl groups of said composition before polymerization is between 0.93 and 1.3 and in that said composition further comprises at least one chromophore agent at least partially filtering ultraviolet wavelengths of less than 400 nm or at least a chromophore agent at least partially filtering wavelengths of the blue light range between 400 and 500 nm or both agents simultaneously. 2. Composition according to claim 1, characterized in that said molar ratio is between 0.96 and 1.1. 3. Composition according to claim 1 or 2, characterized in that said at least one first compound is selected from the group consisting of polyethers, polyesters, polycarbonate-polyols, polycaprolactone-polyols, polybutadiene-polyols, sulfur-containing polyols. , fluorinated polyols and mixtures thereof. 4. Composition according to claim 3, characterized in that said at least one first compound is selected from the group consisting of polytetrahydrofuran, polypropylene glycol, polyethylene glycol, poly- (1,6-hexanediol-carbonate) -glycol, poly - (diethylene glycol-adipate) diol, poly (hexamethylene-2,2-dimethylpropylene glycol adipate) diol and mixtures thereof. 5. Composition according to claim 1, characterized in that the said at least one chromophore agent at least partially filtering wavelengths of the ultraviolet range of less than 400 nm is chosen from the group consisting of benzophenones, anthracenes, benzatriazole derivatives and mixtures thereof. 6. Composition according to claim 5, characterized in that said at least one chromophore agent at least partially filtering wavelengths of the ultraviolet range of less than 400 nm is selected from the group consisting of 2,4-dihydroxybenzophenone- vinylanthracene, 2- (20-hydroxy-30-methallyl-50-methylphenyl) -benzotriazole, 2- (5-chloro-2H-benzotriazol-2-yl) -6 - ((1,1-dimethylethyl) -4 -methyl) -phenol, 2- [20-hydroxy-50- (b-methacryloyloxyethoxy) -30-t-butylphenyl] -5-methyl-2H-benzotriazole, 2- [20-hydroxy-50- (g-) methacryloyloxypropoxy) -30-t-butylphenyl] -5-methyl-2H-benzotriazole and mixtures thereof. 7. Composition according to claims 5 or 6, characterized in that it comprises from 0.001 to 1% by weight, preferably from 0.01 to 0.5% by weight, of said chromophore agent filtering at least partially wavelengths. in the ultraviolet range below 400 nm. 8. Composition according to claim 1, characterized in that said at least one chromophore agent at least partially filtering wavelengths of the blue light range between 400 and 500 nm is selected from the group consisting of N-2- [3- (20-methylphenylazo) -4-hydroxyphenyl] ethyl-methacrylamide, methyl-2-hydroxy-5 - ((4-hydroxyphenyl) azo) -benzoate, N, N-bis- (2-methacryloyl) - ethyl) - (4-phenylazo) aniline and mixtures thereof. 9. Composition according to claim 8, characterized in that it comprises from 0.001 to 1% by weight, preferably from 0.01 to 0.5% by weight, of said chromophore agent at least partially filtering the wavelengths of the domain. blue light between 400 and 500 nm. 10. Composition according to any one of claims 1 to 9, characterized in that said at least one second compound is selected from the group consisting of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate , 3,3'-dimethyl-4,4'-biphenyl diisocyanate and mixtures thereof. 11. Composition according to any one of claims 1 to 10, characterized in that it further comprises a chain extender selected from the group consisting of diols, amino-alcohols, diamines and mixtures thereof. 12. A composition according to claim 11, characterized in that said chain extender is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, butanediol, hexanediol, ethanolamine and their mixtures. 13. A method for manufacturing implantable lenses from a polymerizable composition based on at least a first compound comprising at least two hydroxyl groups and at least one second compound comprising at least two isocyanate groups, comprising: a step mixing said at least one first compound with said at least one second compound so as to obtain a prepolymer having a molar ratio between isocyanate groups and hydroxyl groups of between 0.93 and 1.3, a step of addition to the prepolymer of a chain extender for obtaining a mixture of prepolymer and chain extender, - a step of adding at least one chromophore agent at least partially filtering ultraviolet wavelengths lower than 400 nm and / or at least one chromophore agent at least partially filtering wavelengths of the blue light range included between 400 and 500 nm to the mixture of prepolymer and chain extender, - a step of thermally polymerizing said prepolymer and chain extender mixture with formation of a polymer, and - a step of forming said implantable lenses from said polymer obtained. 14. The method of claim 13, characterized in that said polymerization step forms a polymer having a water absorption rate of less than 5%. 15. The method of claim 13 or 14, characterized in that said polymerization step is carried out by heating at a temperature between 50 and 150 ° C, preferably between 80 and 110 ° C. 16. Method according to any one of claims 13 to 15, characterized in that said forming step is preceded by a step of melting said formed polymer followed by injection into a mold. 17. Method according to any one of claims 13 to 16, characterized in that said forming step is carried out directly in a mold. 18. Method according to any one of claims 13 to 17, characterized in that it further comprises at least one additional step of sterilizing said implantable lenses. 19. The method of manufacturing implantable lenses according to claim 18, characterized in that said additional sterilization step is performed by steam sterilization. Implantable lenses as obtained according to the method of any one of claims 13 to 19. 21. Use of a polymerizable composition according to claim 1 for the manufacture of implantable lenses. 22. Polyurethane for the manufacture of implantable lenses polymerized from a composition according to claims 1 to 12.