FR2528982A2 - Tinting of polyurethane sheet or laminate by immersion in dye - then fixing used for eye lenses with adjustable properties to suit aphakia or retinitis pigmentosa victims - Google Patents

Abstract

Process for tinting a transparent polyurethane comprises (a) colouring by immersion in a continuously agitated bath comprising colourant(s) dispersed in an aq. soln. contg. a surfactant or wetting agent; and (b) fixing by heating and rinsing. Process is used in opthalmic applications partic. as corrective lenses for eyeglasses. The filtering properties may be adjusted according to the degree of evolution of retinal alteration due to aphakia or retinitis pigmentosa.

Description

In the ophthalmic medical field, it has recently appeared that physical remedies could be provided for certain eye diseases which until then were reputed to be very difficult to treat, while retaining the faculty of day vision. Two common examples of these diseases are as follows 10 / "Aphaquiet
This disease results from the absence of the lens of the eye due most often to a surgical intervention. Since the crystalline lens has the function, inter alia, of protecting the retina from ultraviolet radiation by optical absorption from a wavelength of the order of 42Q nm to 440 nm, it is clear that any filtering device capable of fulfilling the function of the crystalline lens disappeared would be an appreciable advantage for the patient.

20 / "Retinal pigmentation"
This disease is the result of the alteration, at first, of the "nocturnal" photo-receptors (generally called rods) of the eye. These photoreceptors, generally located in the periphery of the retina, are, by their sensitivity curve - the maximum of which is at 510 nm, responsible for night vision while being little responsible for recognizing colors: simply the gray and shadows (see in this regard the description given with regard to FIG. 1 of the European patent application published on December 16, 1981 under No. 41,789).

The "daytime" photo-receptors of the eye (generally called cones) occupy the center of the retina and have a maximum of sensitivity around 560-565 nm (see this same figure 1); they are responsible for daytime vision and color recognition,
The alteration of these photo-receptors (rods and canes) can have the most diverse causes such as bruising or mechanical injuries, accidental prolonged irradiations (electric arc, sun ... *), but also bacterial infection (rarely viral) and above all retinal degeneration.

It is generally accepted that retinal degeneration and bacterial infections of canes and rods can be greatly curbed by protecting them from harmful radiation. It is furthermore also accepted that the alteration of the rods is much faster than that of the cones. It is therefore understandable that a filter would allow the rods of the eye to be protected from harmful irradiations. However, with regard to their protection, the selection of an ultraviolet filter must be accompanied by a certain number of precautions such as:
- possibilities to filter light both in the presence and in the absence of sun,
- possibility of saving the sensitivity of the canes, thus allowing the patient to preserve the recognition and the distinction of colors.

Photochromic filtering glasses were proposed by ML WOLBARSHT and others in "RETINITTS PIGMENTOSA CLINICAL IMPLICATIONS OF CURRENT RESEARCH"
Advance in Experimental Medecine and Biology, volume 77, pages -181 to 190, Plenium Publishing Corp., New York. To these proposals, it is advisable to add the above-mentioned European patent application relating to a photochromic filtering product meeting the medical needs presented here but whose application is only possible with certain glassy compositions. This European patent application uses a surface reducing treatment of certain metal oxides contained in the base glass, a treatment which results in glasses having preserved their photochromic properties but also having the required filtering properties.

Unfortunately, this treatment is only applicable to a limited number of vitreous compositions: those which contain easily reducible metal oxides.

 However, in ophthalmic eyewear, it is common to use glasses having particular properties of refractive index and of dispersion, even even a combination of several glasses of different index sealed to each other in the same leritille commonly called lens multi-focal, these lenses can in this case be photochromic or not.

 The present invention provides a method applicable to any type of support without any distinction, guaranteeing the product obtained filtering properties pdtééesOlautfOnouhaits medical and adjustable according to the degree / retinal alteration of the patient.

 In French patent application No. 81 18678 for "Laminated ophthalmic glass and its manufacturing process" filed on October 5, 1981, is described a laminated triple layer lens structure usable in eyewear, said lens being formed of an outer thickness in glass and an inner layer of an optically transparent thermosetting polyurethane which is welded to the glass by means of a thin layer of an optically transparent thermoplastic polyurethane. According to this French patent application, the overall thickness of the duplicate or integral polyurethane composite sheet used is between 0.25 and 0.55 mm with a thickness of thermoplastic layer from 0.04 to 0 0.06 mm and a thickness of thermosetting layer from 0.2 to 0.5 mm.

 - Referring to this French patent application, the main patent to which this certificate of addition is attached, specifies the dyeing operations for the polyurethane duplicate: the actual coloring operation is carried out by immersing the polyurethane in a bath maintained under permanent stirring and formed from a dispersion of one or more dyes in an aqueous solution containing a surfactant additive or wetting agent, this coloring operation being supplemented by a fixing operation which is carried out by heat treatment and rinsing in particular in a boiling aqueous solution of sodium alkyl sulfonate of the kind known under the brand "Teepol".

 If the main patent mentions the applications of such a polyurethane doubling dyeing method for the production of spectacle lenses- lenses for instruments, windows- for vehicles, windows of buildings and other glazing, it does not however envisage any application in the medical field.

 The present invention on the other hand expressly relates to the application in the medical field of the method of dyeing polyurethane with special dyes enabling filters to be obtained which fully meet the criteria and specifications developed very recently.

 The examples below will allow a better understanding of the methodology recommended by the present invention.

 - EXAMPLE 1: Obtaining filter glasses in the 550 nm range intended for patients suffering from retinal pigmentation.

The dyes used are of the "plastoso lubles"type> generally prepared and developed in a dispersed state for synthetic fibers of the textile industry, as specified in the main patent (it will be recalled that these dyes are of the so-called type commonly ACR in trade and can title obtained for example from the Technical Company
Chimique Nouvelle, 8 allée Marie-Louise, 92240 MALAROFF).

In the case of the present example, a coloring mixture is produced according to the traditional techniques of the primary coloring mixtures in the following weight proportions
Red 3443 ACR 70%
Blue 3438 ACR 4%
Yellow 3441 ACR 26%
The dye bath is obtained by diluting in distilled water with electrical resistivity 10 to 17MQ-cm maintained at 60 - 70 "C by heating in a bain-marie with association of a wetting agent of type 3782 ACR in the following proportions of dye concentration
Cc and wetting agent Cm:
Cc = 2 g / l of water
Cm = 4 g / l of water
or a Cm / CG ratio = 2.

 The entire dye bath thus obtained is then brought to 800C + iQC and subjected to continuous stirring eliminating the risk of preferential segregation of one or more of the basic dyes.

After thermal stabilization of the dye bath, the coloring operation is then possible
it is carried out by immersion of the lenses coated with polyurethane or / and pieces of polyurethane in
the state, during a soaking time of 20 minutes + 1 min.

This coloring operation finished, it is
then proceeded to the step of fixing the dyes in
the polyurethane structure by the following technique:
- parts processing: 1 hour at 1250C + 50C.

- rinsing: 10 minutes in an aqueous solution
boiling sodium alkyl sulfonate at a rate of 30cc
per liter of water
In the present case, the glass forming the support
base is of the photochromic type called "PHOTOGRAY EXTRA"
(code 810.55 from the French company CORNING-FRANCE, or
code: 8111 of the CORNING GLASS WORKS Company of the States
United) already recommended in the European patent application
above for a similar destination but in uti
reading a surface reducing treatment.

This glass, 1.8 mm thick and to which is
associated a composite sheet in one piece in poly-
0.45 mm non-tinted urethane, constitutes
a blank lens with optical transmission in function
wavelength in nm, at room temperature
of 220C, is illustrated by curves nO 1 and 2 (figure 1)
corresponding to the clear state and the state respectively
clouded. The curves are also shown opposite.
NO 3 and 4 of optical transmission of the same lens but this time tinted, under the same conditions of temperature (220C) and state (clear and darkened), the poly urethane having undergone the treatment of coloring and fixing of the present invention.

 All of these transmission measurements and the typical characteristic calculations for this type of product were obtained using a HEWLETT-PACKARD type 8450 A spectrophotometer.

As stated in "Photic Damage in Retinitls
Pigment osa and a Suggestion for a Protective Device "by W. ADRIAN and I. SCMMIDT in the journal" Journal
American Optometric Association ", 46, pages 380-386, April 1975, and in" Protective Spectacles for Retinities
Pigmentosa Patients "by R. EWERSON and I.SCHMIDT in the same review, volume 47, pages 738-744 of June 1976, in the case of glasses having a cutoff at 550 nm (as in the case of the present example), it is - important to reduce the optical transmission to the level of sensitivity of the canes - called "photopic transmSitance" in the cited English language documentation - and to reduce as much as possible the optical transmission to the level of sensitivity of the sticks - called "scotopic transmittance" in the English-language documentation cited - this in order to preserve the relief and the distinction of hues for people suffering from retinal pigmentation.

The following values are generally accepted for a perfect filter:
t'Scotopic transmittance "<3%
"Photopic transmittance"> 17 96.

For the present example, from the optical measurements carried out as indicated in FIG. 1, the percentage was calculated using the chromaticity of the illuminant C from the company ICI (see description opposite FIG. O of the main patent) "photoplc and scotopic transmittances" and the results were obtained on 8 tests, from Table I below:
TABLE I
"Scotopic%""Photopic%"# cutout
(nm)
1 1.80 19.11 553.8
2 1.89 19.53 553
3 2.15 20.75 553.6
4 1.81 19.29 553
5 2.16 20.96 554.2
6 1.97 20.12 554.2
7 1.96 20.19 554.2
8 2.20 21.30 553.1
Results show process stability
in which we enriched the dye bath with reason
0.5 g / l of mixture (dye + wetting agent) depending on the
original composition in all even numbered trials.

These results establish the ease with which the
product obtained meets the physical characteristics
hated by the user.

EXAMPLE 2 s Influence of the soaking time in the product
tion of filter glasses at 550 nm0
In order to analyze the flexibility of the dyeing process
of the present invention, the impact has been determined
what can the soaking time have in the dye bath
on the physical characteristics of the filter obtained: we have
studied soaking times between 15 min and 1 hr. In
the dye bath prepared as in Example 1, in
using the coloring and fixing technique
rants indicated in this same example, the study of the influence
soaking times conforms to the results indicated
in Figure 2. It appears that you can adjust at will
the absolute value of the cut thanks to the flexibility per
implemented by the present invention.

Regarding the influence of trem times
page on "photopic and scotopic" transmissions, we
refer to Table II where, for each soaking time,
the corresponding values of the various physical characteristics are indicated
TABLE II
Time -from- "Scotopic%""Photopic%" Cut page in minutes in rfln
15 mins
Curve No. 5 2.99 22.55 547.9
20 mins
Curve No. 6 1.89 19.53 553
30 mins
Curve 7 1.35 16.14 558
1 hour
Curve ne 8 '93 13.86 562.7 - EXAMPLE 3 r Obtaining a filter for aphaca.

 Obtaining filters for patients with lens operations - commonly called aphaca - involves the production of spectacle lenses (corrective or not) having cut-off wavelengths generally between 420 nm and 550 nm and more specifically three characteristic wavelengths which are: 516, 523, 531 nm.

In this example, two dye mixtures were produced according to the process described in Example 1 but with different concentrations and types of primary dyes. The proportions by weight of these mixtures are as follows:
MIX A A MIX B
Orange 3439 ACR: 98% Red 3443 ACR: 42%
Blue. 3438 ACR: 2% Blue 3438 ACR: 4%
Yellow 3441 ACR: 54% the Cm / Cc concentrations of dye and wetting agent are always in the ratio of 2, that is to say:
Cc = 2 g / l of water
Cm - 4 g / l of water.

 After dyeing with different soaking times and fixing of the dyes in the polyurethane structure, we carried out, for each of the mixtures chosen in the present example, transmission measurements and determination of the cuts obtained.

Figures 3 and 4 show the results which have been obtained with regard to the values of the cuts obtained as a function of the mixtures chosen and the soaking times used. Table III indicates the cuts thus obtained in the field considered:
TABLE III
Né lange A Mixture B
Soak time (Figure 3) (Figure 4)
Cutoff (in nm) Cutoff (in nm)
15 mins
Curve NO 9,491
30 mins 514
Curve # 10
I Hr
Curve 11,524
15 mins
Curve n0 12 30 min 543
Curve 13
i hr
Curve no 14,550
This Table III perfectly shows the possibilities offered by the present invention for obtaining selective filters applicable in medical eyewear.

In addition, one can note the flexibility of the process of the present invention which is in no way limited to a type of support, but can be associated with any glasses used in ousphthalmic sunglasses such as
- photochromic or non-mineral glasses, whatever their index and dispersion,
- organic glasses whatever their chemical composition.

 For all these materials, no restriction is made by the process of the present invention with regard to the shapes, levels of curvature and complexity of the surfaces used.

 It goes without saying that the embodiments are only examples and that they could be modified, in particular by substitution of technical equivalents, without departing from the scope of the invention.

 In particular, one can very well extend the absorption range of ultraviolet radiation in the range between 350 and 400 nm, without the appearance of coloration, as is commonly encountered in other similar cases of absorption in this area. wavelength.

 For this, a commercially available type W 4249 absorbent is mixed with distilled water at a rate of 1 gram per liter of water, then brought to 80 ° C. + 10 ° C. At this temperature, the glasses are immersed in the bath for times of between 7 and 60 minutes and more precisely between 7 and 30 minutes, depending on the cut desired.

 Following this operation, a step.

fixing is then undertaken by immersion in a bath perfectly comparable to that specified above (10 minutes at boiling point in 30 cc / liter of Teepol).

 The term "cut" used above 8 'is generally understood to be the intersection of the tangent to the transmission curve with a parallel to the abscissa from the ordinate point 0% of transmission, but it is obvious that any other evaluation method of this "cut" could be retained without departing from the scope of the present invention.

Claims (8)

 1. Application to ophthalmic medical eyewear for patients with aphakia, retinal pigmentation or other eye diseases, of the transparent polyurethane dyeing process according to any of claims 1 to 8 of the main patent or in the The scope of claim 9 or 10 of the main patent, the polyurethane being tinted so as to filter out harmful ultraviolet radiation.  2. Application according to claim 1, characterized in that the dye or dyes dispersed in the stirred polyurethane immersion bath are chosen so that the tinted polyurethane acts as a selective filter having a virtually zero transmission in a range of so-called cut-off wavelength which is between approximately 350 and approximately 560 nm.  3. Application according to claim 2, characterized in that the filter has a selective cutoff at around 550 nm and is therefore suitable for patients with retinal pigmentation.  4. Application according to claim 3, characterized by the primary mixture of the following dyes in weight percentage t  Red 3443 ACR 70%  Blue 3438 ACR 4%  Yellow 3441 ACR 26%.  5. Application according to claim 2, characterized in that the filter has a selective cut-off in the range from approximately 420 nm to approximately 550 nm and more precisely to the three characteristic wavelengths of approximately 516, 523 and 531 nm , this filter being therefore suitable for patients with aphakia.  6. Application according to claim 5, characterized by the primary mixture of the following dyes in percentage by weight  Orange 3439 ACR 98%  Blue 3438 ACR 2%.  7. Application according to claim 5, characterized by the primary mixture of the following dyes in percentage by weight:  Red 3443 ACR: 42%  Blue 3438 ACR: 4%  Yellow 3441 ACR: 54%  8. Application according to claim 2, charac  in that the selective filter obtained is located  in a range between approximately 350 nm and approximately 400 nm, without giving rise to an observable coloration.