CA1260193A - Soft contact-optical objects - Google Patents
Soft contact-optical objectsInfo
- Publication number
- CA1260193A CA1260193A CA000497140A CA497140A CA1260193A CA 1260193 A CA1260193 A CA 1260193A CA 000497140 A CA000497140 A CA 000497140A CA 497140 A CA497140 A CA 497140A CA 1260193 A CA1260193 A CA 1260193A
- Authority
- CA
- Canada
- Prior art keywords
- lens according
- copolymer contains
- lenses
- cross
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
- G02B1/041—Lenses
- G02B1/043—Contact lenses
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F226/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
Abstract
ABSTRACT
Soft contact-optical objects The invention provides soft contact-optical mouldings, in particular contact lenses and hard lenses, from cross-linking, hydrophilic copolymers of olefinic unsaturated compounds, which contain N-alkyl-, N-vinyl carboxylic acid amides as hydrophilic monomer component in addition to the monomers known per se from contact optics. The mouldings according to the invention have a lower water absorption capacity than conventional soft lenses, better compatibility over long periods of wear and show no tendency towards the migration of low molecular weight constituents.
Soft contact-optical objects The invention provides soft contact-optical mouldings, in particular contact lenses and hard lenses, from cross-linking, hydrophilic copolymers of olefinic unsaturated compounds, which contain N-alkyl-, N-vinyl carboxylic acid amides as hydrophilic monomer component in addition to the monomers known per se from contact optics. The mouldings according to the invention have a lower water absorption capacity than conventional soft lenses, better compatibility over long periods of wear and show no tendency towards the migration of low molecular weight constituents.
Description
. .
Sof~ co~t~ct-eptical ~bjects Thi~ invenLion relates to soft contact-optical ~ouldin~ , in ~articular contact len~es and scleral lense~, from cross-li~kin~, hydrophilic copolymers of olefi~ic un~aturated compou~d~, which contain N-alkvl-N-vinyl carboxylic acidamides as hydrophilic monomar component in addition to the monomers kno~n ~ sa fro~
contact optic~ The mouldings accordin~ to the invention have a lower water absorption capacity tha~ convantional ~oft lense~, better compatibility over long p~riods of wear and ~how no tendency towards the migration of low molecular wei~ht constituents.
Soft hydrophilic contact lenses of hydroxyethyl
Sof~ co~t~ct-eptical ~bjects Thi~ invenLion relates to soft contact-optical ~ouldin~ , in ~articular contact len~es and scleral lense~, from cross-li~kin~, hydrophilic copolymers of olefi~ic un~aturated compou~d~, which contain N-alkvl-N-vinyl carboxylic acidamides as hydrophilic monomar component in addition to the monomers kno~n ~ sa fro~
contact optic~ The mouldings accordin~ to the invention have a lower water absorption capacity tha~ convantional ~oft lense~, better compatibility over long p~riods of wear and ~how no tendency towards the migration of low molecular wei~ht constituents.
Soft hydrophilic contact lenses of hydroxyethyl
2~ methacr~lat~ ~HEMA) were developed in the vears 1963 to 1965 ~espe~iallv in the USSR~. This typ~ of lens was very quickly accepted by contact l~s wQarers owin~ to th~ir comfort. Th~ mechanical stress on Lhe corneal tissu~ i5 lo~er with soft lenses than ~ith hard lenses; moreoverJ
the metabolism of the cornea is influenced to a lesser ~ extent.
: ~ : Simple ad~u~tm~nt, short acclim~tization and ~ood : wear;n~ comfort were decisive fàctor~ in making soft hydrophilic lens~s capture a ~ubstantial proportion of th~
: ~o mark~t within a short time~
~ : A~ter over a decade of experience with HEMA lenses, : . disa~vanta~ffs havs, however, al50 become known in this ;: ~ro~ of materials. Thus, the compatibility i8 impaired :, ~ :
~ Le A 23 477 : :
~; ,"., :;
': ` '`',,~' aft~r wearinq soft hydrophilic HEMA lenses for a r01ativelv lon~ time. The ca~ses of this li~ especially in preservative3 contained in caring a~ents, caring a~ents in conjunction with tha len~ material and d~maging effects of the mat2rial itself. HEMA material6 can cau3e toxic dama~e to ~he eye. In the clinical picture, such dama~3 in addition ~o ~he complaints ~ujecti~ely mado by contact le~s wearer~, can be recognized from hypere~ia in the limbus region and broadeninas of the border tachyphagia ves~al network with more or less substantially formsd corneal vascularizationc. The lstter ar0 ;rraYersable and occur not seldom without sujective complaint~. Re~idual monomers and cros~-linkin~ aqents contributa to thisO
Their influenc~ on the biological compatibility is demonstrable.
Similar manifestations can al o be detacted when wearing contact lenfia~ from copolvmer~ of HEMA.
"HEMA-free" pol~ars or copolymers, such as polvvinyl pyrrolidone or vinyl pyrrolidonelmethyl methacryla~e copolymers have been used for some time for highly hydrophilic contact lenseQJ they should have a be~ter eya compatibili~y than HEMA lenæes. These so-called hydrogel lenses are hydrophilic polymer networks based on water-soluble monomers, which are capable of absorbing from 25 to over 70% by weight of wat~r, bas~d on the hydrated form, and whi~h soften as a resul~ of absorbing water. The ~ N-vinyl lac~am~ in co~bination with polvallyl cross-lin~ing agents have achieved an important role among the watar-soluble monomers. US Pa~en~ 4 158 089 and ~uro~ean Pa~ent~ 79 720, 79 721, 106 650 a~ well as Sh~ll PD1Vm, 7 ~1983) 9 no. 3 p~ 69-71 are mentioned, for example, as
the metabolism of the cornea is influenced to a lesser ~ extent.
: ~ : Simple ad~u~tm~nt, short acclim~tization and ~ood : wear;n~ comfort were decisive fàctor~ in making soft hydrophilic lens~s capture a ~ubstantial proportion of th~
: ~o mark~t within a short time~
~ : A~ter over a decade of experience with HEMA lenses, : . disa~vanta~ffs havs, however, al50 become known in this ;: ~ro~ of materials. Thus, the compatibility i8 impaired :, ~ :
~ Le A 23 477 : :
~; ,"., :;
': ` '`',,~' aft~r wearinq soft hydrophilic HEMA lenses for a r01ativelv lon~ time. The ca~ses of this li~ especially in preservative3 contained in caring a~ents, caring a~ents in conjunction with tha len~ material and d~maging effects of the mat2rial itself. HEMA material6 can cau3e toxic dama~e to ~he eye. In the clinical picture, such dama~3 in addition ~o ~he complaints ~ujecti~ely mado by contact le~s wearer~, can be recognized from hypere~ia in the limbus region and broadeninas of the border tachyphagia ves~al network with more or less substantially formsd corneal vascularizationc. The lstter ar0 ;rraYersable and occur not seldom without sujective complaint~. Re~idual monomers and cros~-linkin~ aqents contributa to thisO
Their influenc~ on the biological compatibility is demonstrable.
Similar manifestations can al o be detacted when wearing contact lenfia~ from copolvmer~ of HEMA.
"HEMA-free" pol~ars or copolymers, such as polvvinyl pyrrolidone or vinyl pyrrolidonelmethyl methacryla~e copolymers have been used for some time for highly hydrophilic contact lenseQJ they should have a be~ter eya compatibili~y than HEMA lenæes. These so-called hydrogel lenses are hydrophilic polymer networks based on water-soluble monomers, which are capable of absorbing from 25 to over 70% by weight of wat~r, bas~d on the hydrated form, and whi~h soften as a resul~ of absorbing water. The ~ N-vinyl lac~am~ in co~bination with polvallyl cross-lin~ing agents have achieved an important role among the watar-soluble monomers. US Pa~en~ 4 158 089 and ~uro~ean Pa~ent~ 79 720, 79 721, 106 650 a~ well as Sh~ll PD1Vm, 7 ~1983) 9 no. 3 p~ 69-71 are mentioned, for example, as
3~
Le A Z3 47?
,, ~2~i0~13 prior art. Soft hydrogel lenses initially have high wearing comfort owing to their ~oftness and moulding abili~y compared with lenses from hard and semi-hard materials with low water absorption capacity, for example polymethyl methacrylate, polysilyl methacrylatesJ
cellulose ace~obutya~e among others, but suffer from the disadvantage ~hat they can easily be mechanically damaged. To increase tensil0 strength, it was thus proposed to add from 0.9 to 5% by weight of methacrylic acid to the monomer mixture ~see European Patent no.
106 650). Rasidual monomeric methacrylic acid, however, has a high toxic e~fect in contact lens materials, so that a method must be sought for achieving a high mechanical strength without addi~ion of methacrylic acid.
With lenses Df N-vinyl lactam monOmQr-containing polymers, i~ i5 often observed that a slight clouding and brown colouring occurs aftar a relatively long wearing time. Hydrogel lenses, moreover, suffer from tha disadvantage that they can be easily damaged, require intensive care and can store and absorb metabolic products, caring agenta as well as bacteria.
In recent years, new lenses have been developed from hard and semi-hard materials, for example polysilyl mothacrylates, cellulose acetobutyrate among others, with low water absorption capacity9 which in the meantime have captured a considerable proportion of the market Good compatibili~y, simple care and good optical properties of ~hs ma~erial are hereby decisive factors.
Al~hough the development of these lens ma~erials can be evaluated positively, the desire for a soft, rubber-elastic materia~l with low water absorption, par~icularly ::
~ ; Le A 23 477 .~
. , .
'' ' ' ' ~' , ~ . - ' ..,' ... " ': ' i33 "
for exte~ded wear lensas, ha~ existed for a lon~ time.
This desire could be partiallv met by lenses of ilicon~
rubber. With th~ silicone lens, however, problems occur with ~he ~ettabilitv~ Furthermor~, they have ~o be cast in a special production process. Tha cheaper rotating procsss cannot be appliad in the case of silicone rubber.
la An obi~ct of tha invention was to find a new ma~erial which combines ~he advantages of Lhe hard materials~ such as good optical proper~ies, relatively low water absorption capacity, low care expenditure and productability of thin lenses a~ a result of tha mechanical stability of the material, with the advantages of soft9 rubber-elastic materials, such as low mechanical stress on th2 eye ti sue, high wearing comfort etc.
It was fourd that ~h~ ob~ect can be achieved when in the production of the cross-linking copolymer an N-al-kyl-N-vinyl carboxylic acid amide ars simultaneou~ly used as hydrophilic monomar, optionally in addition to other hydrophilic monomers.
The present invsntion provides contac~-optical mo~ldings, in particular contact lenses ard scleral 2~ lensest from water-absorbing, cross-linking copolv~ers Df olefinic unsatura~ed monomers, characterised in that ths copolymer contain~ polvmerised from 5 to 55% by weight, preferably from 8 to 40% by weiyht, particularly prefarably from 10 to ~5% by weight of an N-vinyl amide of the general formula O
: : ~
R-C-~-CH=CH2 ~5 R
`:
:
Le R 23 477 .
- :
.
231~9 6137 wherein R and R' represent, independently ~rom each other, C1-C4-alkyl yroups, preferably methyl, with the proviso that R and R' cannot both be methyl.
The N-methyl-N-vinyl amides of acetic acid, propionio acid and butyric acid are preferred accordlng to the lnvention.
In additlon to the monomer components which are important for the invention, monomers known per se from contact optics can be used in the production of the copolymer, whereby aliphatic, cycloallphatic, aromatic and araliphatic methacrylic acid esters having ~orm 1 to 8 carbon atoms in the ester part are preferred. ~xamples o~ these are methyl-, ethyl-, n-, i- and t-butyl, cyclohexyl-benzyl- and phenyl methacrylate, in part~cular methyl ~ethacrylate and the butyl methacrylates. A further preferred class of monomers are the above-mentloned vinyl lactams, ln particular ~-vinyl pyrrolidone.
Examples of further monomers known per se are generally the C1-C12-alkyl- or cycloalkyl esters o~ acrylic acid or methacrylic acid; methacrylic acid; acrylic acid; monohydroxy- or dihydroxy-C2-C6-alkyl esters of (meth)acrylate acid as well as the alkyl ethers thereof such as 2-hydroxyethyl methacrylate, 2-hydroxy-ethyl acrylate, 2,3-dihydroxypropyl methacrylate, 1,4 butandiol-monoacrylate, 2-ethoxye~hyl methacrylate; glycidyl ~ethacrylate; vinyl acetate, vinyl laurate, vinyl propionate, vinyl versate, as well as methacrylic acid-2- oxyethyl ethyl esters.
~; The oopolymers to be used accor~ing to the invention ... ~... . .. .
.. , :
: ~.;"' ' "', : ' -'~ ~, . " " ' ' ' ~.... ..
~, .
mUc~ be cross-linked.
The cross-linking can bs carried out in a known manner, for example by ~he influence of high-energv radiation~ for exampla elactron radia~iont on the finished copolvmer or by the ~imul~aneous U5e of from 0.01 to 3%
by wei~h~, preferably from 0.1 to 2% by waight, in particular from 0.2 to l'X. by wei~ht, of at least two olefinicallv unsaturated ~roup-containin~ cro~s-linking agents during copolymerisation.
Cross-linking agents which are suitable according to the invention are A) (meth)acrylic ester cros~-linking a~ents and/or B) vinyl or allyl cross-linkin~ agents. The cross-linking agents A) are compounds known per se, which in addition to a ~meth)acrylic ester ~roup have at least one further ol;finically ~nsaturated group of the same kind or diff~rent. Amon~ these are acrvlic acid or methacrvlic acid esters of polyfunctional alcoh~ls, for example ethvlene glycol dimethacrylate, propylene glycol diethyl acrvlate, diethvlane glycol dimethacrylate triethylene glysol dimethacrvlat~, polyethylene glycol dimethacrylate, 1,4-~utandiol dimethacrylats, 1,6-hexandiol dimethacrylate, trimethylol propane trime~h-acrylate, pentaerythrita-tri- and tetramatha~rylata, methyl-lt5 pentandiol-dim~thacrylate, dih~drodicyclo-pentadianyl monomethacrylate, allyl methacrylate, vinyl methacrylate, bisphenol-A-dimathacrylata, as well as the correspondin~ acrylic acid esters.
The cross-linking agents B) have at least two olefinically unsaturated groups ~vinyl or allyl ~roups), howevar, n~ ~m~th~acrylic ester groupin~. Examples of tho_a monomers known 0r se are butandiol-divinyl ether~
:~ LQ A_ 23 477 :: :
.
:
. ~`
divinvl e~hvlene urea, divenyl propolylene ur~a, divinyl adipate, divenvl benzene, divinyl phthalate, triallvl cyanurate, triallyl isocyanurate, diethyl2ne glycol diallyl carbonate, diallyl maleate, diallyl i~aconate, trimethylol propane-di- and triallyl other, triallyl trimellita~e, N,N-diallyl mel2mines etc.
The cross-linkin~a aaents D) and cross-linkin~ a~ents E) in a weiaht ratio of from 1:3 ~o 3:1, preferably frDm 1:2 to 2:1, in particular about 1:1, are preferably used in the copolvmerisation. The combination of the ~wo typas of cross-linking a~ent is advanta~eous for the transparen-cv and radii st~bilitv of the lenses and shells producedfro~ ths copolvmer and results in the matarials continaing only verv low proportions (<0.5% by weight) of water-extractable portions.
Tha cross-linked copolv~ersiation of th2 olefinicallv ~ unsaturated monomer~ can take place accordin~ to the con-ventional ~achniques of rad;cal polymeri~ation, for xamplo initiated by heat, li~ht or by initiators decompnsin~ in radicals. The li~ht polymerisation is preferred, as described in detail in DE-05 ~ 300 ~45 and Int. Chim. 198~, no. 242, p. 121-1~6~ The polymerisation can ~herebv be carried out as so-called block polymeri-sation in plate chambers, glass tubes or plastics material cups. A preferrèd embodiment is the polymerisation of the constituents in plastic~ material cups of polyolefins~
such a= polvethylene ? polypropylene, polymethyl pen~ene-1 ?
polyamides or polvacetalene. The cups can have a corres-~ondin~ shape for an unfinished product or also for the .
finished lens. The polymerisation ~5 : ~ :
~ Le A 2~ 477 , :~ :
'~
,, :, :
' ` . ~ ' , ~,, , ' ~26~3 can also take place with addition of ethylene glycol which i5 later washed out with water.
Depending on the quanti~y of hydrophilic monomer components in the copolymer, the water absorpt;on capacity thereof is variable within wide lirnits, for e~ample between 6 and 70%, by weight, based on the hydrated condition. Compared with conventional soft lenses, the products accDrding to the invention have the advantage, however, that they can be adapted to a lower water absorption capacity, and in spite of this have the sought af~er wearing comfort on the eye of a soft lens.
The mat3rial to be used according to the invention is outstandingly suitable for the production of thin to very thin extended wear lenses. Owing to the low water absorption, only a slight increase in thickness takes place during hydration. By thin to very thin lenses, are to be understood those lenses with an average thickne s of from 0~04 to 0.15 mm by design for minus lenses (for correcting short-sightedness), or from 0.08 ~o 0.4 mm with plus lenses tcorrection long-sightedness) and from 0.1 to 8~4 mm in the case of aphacia lenses (for correcting aphacia). By corresponding interior geometry (aspherical constructi-on), an increased diffu~ion of lacrimal fluid can be produced as is already the state of the art nowadays with hard lenses, and thus the compatibility on the eye can be increased.
The thin to very thin lenses have an increased permeability to oxygen compared with conventional lenses with an average thickness, of greater than 0~15 mm, which is shown to be preferable, in particular for the extended wear of contact lenses.
: : :
Le A 2 _ 77 '' i ' ' ' ;`
A further advantage of the soft lenses according to the invention is ~hat they do not become cloudy on the eye, even after a relatively long wearing time, ~hey do not turn brown and in addition to outstanding compatibility on the eye, have particularly good radii stability and optical stability.
In con~rast to commercial hydrophilic contac~ lenses based on N-vinyl pyrrolidone, lenses according to inven~ion contain no notable portions which can be extracted with water ~preferably)<0.1% by weight).
The block polymerisation in plate chambers, described in ~he following examples, firstly enables the biolocical charge testing of soft lens materials, since relatively large homogeneous plates ~preferably with a surface area greater than 1 m2) can be produced in a preparation, from which a large number tfor example more than 1000) of finished products with identical chemical composition can be pressed.
:
: Le A 23 477 : :
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Example 1 -- .
Monomer mi~tures of ~he composition lis~ad in ~ha following Table 1 are exposed to radia~ion with a UV
fluorescent lamp in cylindrical cups of poly-4-methyl 1~ pen~-1-ene wi~h a deameter of 12 mm and a height of 4 mm, for 6 days a~ room tempera~ure, The blanks obtained are ~hen annealed for 6 hours at 80C and for 2 hours at 120C. Contas~ lenses are produced from ~he blanks by rotating and polishing.
. -~0 ~ :
: :: 35 Le A 23 477 .
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.
:~. ' ~ ~60 193 o~ ", U) CO o -, ~ ~, , , o C~ ~ o ~ .
U~
~ o S J 1~ I N I I In Q O I O
Lt> U~ O
O ~ . o ~,1 ~ I ~1 ~1 1 1 0 0 1 0 O`
` U~ U~ O
~1 In v I:q I t`~ N IN I t:3 1 0 0 a~
O` Vl . ~n u O
~¢t~ I N I I IO O I O
/ID ~11 ~ _l _ ~ b .~ ~ ~ L, rl ..
. ~ ~ rl .rl 3: ~ x ~
0 ~ 0 ~ b'~:1 I ~ 1 rl v ~ ~U
L, x ~ u ~ _ u ~ r L 111 ~ r~ _ L (D
C U S~I L ~ O
-~1 tll ~ >~ U 0 0 ~ t: ~ L
~ ~ G 1 1: ~ E~ o O ~ J) . o b :~
~ r ~ ; ~ O
.,.. , ~ Lv : ~ o , .~ I C -~
, ,t ~ ~ I a1 ~~ S ~ ~ ~
,~ i~l ,t~ C J ,1~ O
0 O I 111 1 IU rl Ql ~1 ~ ~ -t N
;~ c~ ~ Z; h Le A 23 477 :
~ : .
-, . : , ::
, ,. ' , . ., '`
~2~ 3 Th~ lenses produced from the materials A to E are treat~d for 6 hours at room temperature in a 5% H~02 solution and then dialyzed for 6 days with ion exchange water. No streaks, cloudiness or light scatter can be observed on the hydrated lenses w;th the slit lamp. The properties of the lenses are set out in Table 2:
lS
ZS
:~ 30 .
;~
: ~ 35 : Le A 23 477 "
: ~
~: . : ' '' : '`
:
c~ N O
W N N
In ~ Ct~
a N .
L~
o In O
Cl ~ N .1 In O ~ CO
ttl ~ N
m N 11~ N
¢ t'l N
:: :
~O O
C C ~:
."~
: L. b .a ~ C
~J ~1 >~ ~ L
L L ~
O. D, ~ In Ul ~1 u C
~ C ~ X
O U O O ~1 .rl 0 ~r~ Il) r': a) .c .rl r~ 111 D~ tlll ~5 ~: C~
~ ~ n ~ ~ o (11 0 ~ ul 10 L ~ ~1) t9 ,,~ U~ u~ L. ul b 11~ L b L.
: c: ~ a u ~ 3 ~ ~ ~
~ ~:
Le A 2 3 4 7 7 ~:1 " ~". ., ,,. ., , ~' . ~ :
The ~estin~ of the lenses in an ani~al experiment on the eve of a rabbit re ~lts in a~ood bioco~patibility of the material, even after 21 day~ of ~ninterrupt~d wear.
For determining ~he in~rease in thi~kne~s, dry l~nses, rotated to completion, are stor~d for 6 days in a phvsiolo~ic~l salt solution at 20C. For determining the axtractable portions, the lense3 are washed after storage~
dried for 24 hours at 80C and rewei~hed~ In each case, tha wei~ht 10s5 is less than 0.1% by weight. The radii ~tability i5 about 0005 mm, the li~ht transmission with a layer thickness of 4.5 mm i5 about 90%.
Example 2 Monomer mix~ures of the ~ompositions listed in the follGwin~ Table 3 are filed into glass plate chambers with the measurements Z50 x 250 x 5 mm, provided with a sealin~
cord, under N2 after careful de~assing under vacuum, and exposed to radiation with a UV fluorescent lamp for 6 : 25 days. The plat~s are annealed for 24 hours at 80C and then for 2 hours at 14~ C. Unfinish~d product with a diameter of i2.5 m~ ar~ cut from ths plate6, which have b0en dialyzed for 6 days in deionized water. After drying ths unfinished products, contact lenses Df varyin~
thickness are produced therefrom by rotatin~ and polishin~.
.
~5 : Le A 23 477 : : :
~ ~ "'''' : :: .
.: ' ' ' ~ :
~ ' :
~ ""' ~ ' : ' " ~ . :
~n Lr) o ~ N
o~r)~IIooIo ~o W ~O
.Ln U- O
u) In ~ . . .
a In ~O o, o O`
_.
In Ln O
O o ~
U In _l ~ Ul I OI O
O`
o~ ., U~ Ln O
O ~ ~
U~ O O I O ~O
. U~ U~ o Ln In ~ ~r ~¢ U~ ~ I I O O I O U~
O
~O I
~a ,, .a--_I L
~ ~ In u ~ u ~
.1:! C~ u u ~ t, ~ ~ a x a ~
~ :~ k ~ o C: ~ _ Lu .1 0 :9 ~ ,1 rl a~
O
~ ~L ~1 o ~, :, ~ ~ ,,, ~ u ~ ~ o ~n ~ ~ o a ~
.,-1 ~ O L
1~ ~ L u o ~ c ~ ~ ~ m ~ ,~ b ta ~ .r~ 0 .C ~ C X ~ 1~ -1 ~ 0 L
E~ ~ E3 ~ .~ ~ o ~ r1 ~ O ~ 1 O I ~ N
, ~1:~ æ ~ N
Le A 2 3 4 7 7 ~: :
~. .. , -The measurement of the inner radii with average thickne~ses up to 0.08 mm r2sults in good raddi stabili~ies tvariations 0.1 mm). No streaks or cloudiness ~an be found during testing with the slit lamp. Light transmission 90% with a layer thickness of 4.7 mm. The portion which can be extracted with water is in all cases less than 0.1~/. by weight.
The animal experiment on ~he eye of a rabbit resul~
in good biological compatibility of the material with the eye, e~en after 21 day~ of uninterrup~ed ~ear.
;::
: 35 ; Le A 23 477 `' .
:' :
.
........... . -
Le A Z3 47?
,, ~2~i0~13 prior art. Soft hydrogel lenses initially have high wearing comfort owing to their ~oftness and moulding abili~y compared with lenses from hard and semi-hard materials with low water absorption capacity, for example polymethyl methacrylate, polysilyl methacrylatesJ
cellulose ace~obutya~e among others, but suffer from the disadvantage ~hat they can easily be mechanically damaged. To increase tensil0 strength, it was thus proposed to add from 0.9 to 5% by weight of methacrylic acid to the monomer mixture ~see European Patent no.
106 650). Rasidual monomeric methacrylic acid, however, has a high toxic e~fect in contact lens materials, so that a method must be sought for achieving a high mechanical strength without addi~ion of methacrylic acid.
With lenses Df N-vinyl lactam monOmQr-containing polymers, i~ i5 often observed that a slight clouding and brown colouring occurs aftar a relatively long wearing time. Hydrogel lenses, moreover, suffer from tha disadvantage that they can be easily damaged, require intensive care and can store and absorb metabolic products, caring agenta as well as bacteria.
In recent years, new lenses have been developed from hard and semi-hard materials, for example polysilyl mothacrylates, cellulose acetobutyrate among others, with low water absorption capacity9 which in the meantime have captured a considerable proportion of the market Good compatibili~y, simple care and good optical properties of ~hs ma~erial are hereby decisive factors.
Al~hough the development of these lens ma~erials can be evaluated positively, the desire for a soft, rubber-elastic materia~l with low water absorption, par~icularly ::
~ ; Le A 23 477 .~
. , .
'' ' ' ' ~' , ~ . - ' ..,' ... " ': ' i33 "
for exte~ded wear lensas, ha~ existed for a lon~ time.
This desire could be partiallv met by lenses of ilicon~
rubber. With th~ silicone lens, however, problems occur with ~he ~ettabilitv~ Furthermor~, they have ~o be cast in a special production process. Tha cheaper rotating procsss cannot be appliad in the case of silicone rubber.
la An obi~ct of tha invention was to find a new ma~erial which combines ~he advantages of Lhe hard materials~ such as good optical proper~ies, relatively low water absorption capacity, low care expenditure and productability of thin lenses a~ a result of tha mechanical stability of the material, with the advantages of soft9 rubber-elastic materials, such as low mechanical stress on th2 eye ti sue, high wearing comfort etc.
It was fourd that ~h~ ob~ect can be achieved when in the production of the cross-linking copolymer an N-al-kyl-N-vinyl carboxylic acid amide ars simultaneou~ly used as hydrophilic monomar, optionally in addition to other hydrophilic monomers.
The present invsntion provides contac~-optical mo~ldings, in particular contact lenses ard scleral 2~ lensest from water-absorbing, cross-linking copolv~ers Df olefinic unsatura~ed monomers, characterised in that ths copolymer contain~ polvmerised from 5 to 55% by weight, preferably from 8 to 40% by weiyht, particularly prefarably from 10 to ~5% by weight of an N-vinyl amide of the general formula O
: : ~
R-C-~-CH=CH2 ~5 R
`:
:
Le R 23 477 .
- :
.
231~9 6137 wherein R and R' represent, independently ~rom each other, C1-C4-alkyl yroups, preferably methyl, with the proviso that R and R' cannot both be methyl.
The N-methyl-N-vinyl amides of acetic acid, propionio acid and butyric acid are preferred accordlng to the lnvention.
In additlon to the monomer components which are important for the invention, monomers known per se from contact optics can be used in the production of the copolymer, whereby aliphatic, cycloallphatic, aromatic and araliphatic methacrylic acid esters having ~orm 1 to 8 carbon atoms in the ester part are preferred. ~xamples o~ these are methyl-, ethyl-, n-, i- and t-butyl, cyclohexyl-benzyl- and phenyl methacrylate, in part~cular methyl ~ethacrylate and the butyl methacrylates. A further preferred class of monomers are the above-mentloned vinyl lactams, ln particular ~-vinyl pyrrolidone.
Examples of further monomers known per se are generally the C1-C12-alkyl- or cycloalkyl esters o~ acrylic acid or methacrylic acid; methacrylic acid; acrylic acid; monohydroxy- or dihydroxy-C2-C6-alkyl esters of (meth)acrylate acid as well as the alkyl ethers thereof such as 2-hydroxyethyl methacrylate, 2-hydroxy-ethyl acrylate, 2,3-dihydroxypropyl methacrylate, 1,4 butandiol-monoacrylate, 2-ethoxye~hyl methacrylate; glycidyl ~ethacrylate; vinyl acetate, vinyl laurate, vinyl propionate, vinyl versate, as well as methacrylic acid-2- oxyethyl ethyl esters.
~; The oopolymers to be used accor~ing to the invention ... ~... . .. .
.. , :
: ~.;"' ' "', : ' -'~ ~, . " " ' ' ' ~.... ..
~, .
mUc~ be cross-linked.
The cross-linking can bs carried out in a known manner, for example by ~he influence of high-energv radiation~ for exampla elactron radia~iont on the finished copolvmer or by the ~imul~aneous U5e of from 0.01 to 3%
by wei~h~, preferably from 0.1 to 2% by waight, in particular from 0.2 to l'X. by wei~ht, of at least two olefinicallv unsaturated ~roup-containin~ cro~s-linking agents during copolymerisation.
Cross-linking agents which are suitable according to the invention are A) (meth)acrylic ester cros~-linking a~ents and/or B) vinyl or allyl cross-linkin~ agents. The cross-linking agents A) are compounds known per se, which in addition to a ~meth)acrylic ester ~roup have at least one further ol;finically ~nsaturated group of the same kind or diff~rent. Amon~ these are acrvlic acid or methacrvlic acid esters of polyfunctional alcoh~ls, for example ethvlene glycol dimethacrylate, propylene glycol diethyl acrvlate, diethvlane glycol dimethacrylate triethylene glysol dimethacrvlat~, polyethylene glycol dimethacrylate, 1,4-~utandiol dimethacrylats, 1,6-hexandiol dimethacrylate, trimethylol propane trime~h-acrylate, pentaerythrita-tri- and tetramatha~rylata, methyl-lt5 pentandiol-dim~thacrylate, dih~drodicyclo-pentadianyl monomethacrylate, allyl methacrylate, vinyl methacrylate, bisphenol-A-dimathacrylata, as well as the correspondin~ acrylic acid esters.
The cross-linking agents B) have at least two olefinically unsaturated groups ~vinyl or allyl ~roups), howevar, n~ ~m~th~acrylic ester groupin~. Examples of tho_a monomers known 0r se are butandiol-divinyl ether~
:~ LQ A_ 23 477 :: :
.
:
. ~`
divinvl e~hvlene urea, divenyl propolylene ur~a, divinyl adipate, divenvl benzene, divinyl phthalate, triallvl cyanurate, triallyl isocyanurate, diethyl2ne glycol diallyl carbonate, diallyl maleate, diallyl i~aconate, trimethylol propane-di- and triallyl other, triallyl trimellita~e, N,N-diallyl mel2mines etc.
The cross-linkin~a aaents D) and cross-linkin~ a~ents E) in a weiaht ratio of from 1:3 ~o 3:1, preferably frDm 1:2 to 2:1, in particular about 1:1, are preferably used in the copolvmerisation. The combination of the ~wo typas of cross-linking a~ent is advanta~eous for the transparen-cv and radii st~bilitv of the lenses and shells producedfro~ ths copolvmer and results in the matarials continaing only verv low proportions (<0.5% by weight) of water-extractable portions.
Tha cross-linked copolv~ersiation of th2 olefinicallv ~ unsaturated monomer~ can take place accordin~ to the con-ventional ~achniques of rad;cal polymeri~ation, for xamplo initiated by heat, li~ht or by initiators decompnsin~ in radicals. The li~ht polymerisation is preferred, as described in detail in DE-05 ~ 300 ~45 and Int. Chim. 198~, no. 242, p. 121-1~6~ The polymerisation can ~herebv be carried out as so-called block polymeri-sation in plate chambers, glass tubes or plastics material cups. A preferrèd embodiment is the polymerisation of the constituents in plastic~ material cups of polyolefins~
such a= polvethylene ? polypropylene, polymethyl pen~ene-1 ?
polyamides or polvacetalene. The cups can have a corres-~ondin~ shape for an unfinished product or also for the .
finished lens. The polymerisation ~5 : ~ :
~ Le A 2~ 477 , :~ :
'~
,, :, :
' ` . ~ ' , ~,, , ' ~26~3 can also take place with addition of ethylene glycol which i5 later washed out with water.
Depending on the quanti~y of hydrophilic monomer components in the copolymer, the water absorpt;on capacity thereof is variable within wide lirnits, for e~ample between 6 and 70%, by weight, based on the hydrated condition. Compared with conventional soft lenses, the products accDrding to the invention have the advantage, however, that they can be adapted to a lower water absorption capacity, and in spite of this have the sought af~er wearing comfort on the eye of a soft lens.
The mat3rial to be used according to the invention is outstandingly suitable for the production of thin to very thin extended wear lenses. Owing to the low water absorption, only a slight increase in thickness takes place during hydration. By thin to very thin lenses, are to be understood those lenses with an average thickne s of from 0~04 to 0.15 mm by design for minus lenses (for correcting short-sightedness), or from 0.08 ~o 0.4 mm with plus lenses tcorrection long-sightedness) and from 0.1 to 8~4 mm in the case of aphacia lenses (for correcting aphacia). By corresponding interior geometry (aspherical constructi-on), an increased diffu~ion of lacrimal fluid can be produced as is already the state of the art nowadays with hard lenses, and thus the compatibility on the eye can be increased.
The thin to very thin lenses have an increased permeability to oxygen compared with conventional lenses with an average thickness, of greater than 0~15 mm, which is shown to be preferable, in particular for the extended wear of contact lenses.
: : :
Le A 2 _ 77 '' i ' ' ' ;`
A further advantage of the soft lenses according to the invention is ~hat they do not become cloudy on the eye, even after a relatively long wearing time, ~hey do not turn brown and in addition to outstanding compatibility on the eye, have particularly good radii stability and optical stability.
In con~rast to commercial hydrophilic contac~ lenses based on N-vinyl pyrrolidone, lenses according to inven~ion contain no notable portions which can be extracted with water ~preferably)<0.1% by weight).
The block polymerisation in plate chambers, described in ~he following examples, firstly enables the biolocical charge testing of soft lens materials, since relatively large homogeneous plates ~preferably with a surface area greater than 1 m2) can be produced in a preparation, from which a large number tfor example more than 1000) of finished products with identical chemical composition can be pressed.
:
: Le A 23 477 : :
",~
~' , ' ~26~
Example 1 -- .
Monomer mi~tures of ~he composition lis~ad in ~ha following Table 1 are exposed to radia~ion with a UV
fluorescent lamp in cylindrical cups of poly-4-methyl 1~ pen~-1-ene wi~h a deameter of 12 mm and a height of 4 mm, for 6 days a~ room tempera~ure, The blanks obtained are ~hen annealed for 6 hours at 80C and for 2 hours at 120C. Contas~ lenses are produced from ~he blanks by rotating and polishing.
. -~0 ~ :
: :: 35 Le A 23 477 .
: - ' , ' ;
.
:~. ' ~ ~60 193 o~ ", U) CO o -, ~ ~, , , o C~ ~ o ~ .
U~
~ o S J 1~ I N I I In Q O I O
Lt> U~ O
O ~ . o ~,1 ~ I ~1 ~1 1 1 0 0 1 0 O`
` U~ U~ O
~1 In v I:q I t`~ N IN I t:3 1 0 0 a~
O` Vl . ~n u O
~¢t~ I N I I IO O I O
/ID ~11 ~ _l _ ~ b .~ ~ ~ L, rl ..
. ~ ~ rl .rl 3: ~ x ~
0 ~ 0 ~ b'~:1 I ~ 1 rl v ~ ~U
L, x ~ u ~ _ u ~ r L 111 ~ r~ _ L (D
C U S~I L ~ O
-~1 tll ~ >~ U 0 0 ~ t: ~ L
~ ~ G 1 1: ~ E~ o O ~ J) . o b :~
~ r ~ ; ~ O
.,.. , ~ Lv : ~ o , .~ I C -~
, ,t ~ ~ I a1 ~~ S ~ ~ ~
,~ i~l ,t~ C J ,1~ O
0 O I 111 1 IU rl Ql ~1 ~ ~ -t N
;~ c~ ~ Z; h Le A 23 477 :
~ : .
-, . : , ::
, ,. ' , . ., '`
~2~ 3 Th~ lenses produced from the materials A to E are treat~d for 6 hours at room temperature in a 5% H~02 solution and then dialyzed for 6 days with ion exchange water. No streaks, cloudiness or light scatter can be observed on the hydrated lenses w;th the slit lamp. The properties of the lenses are set out in Table 2:
lS
ZS
:~ 30 .
;~
: ~ 35 : Le A 23 477 "
: ~
~: . : ' '' : '`
:
c~ N O
W N N
In ~ Ct~
a N .
L~
o In O
Cl ~ N .1 In O ~ CO
ttl ~ N
m N 11~ N
¢ t'l N
:: :
~O O
C C ~:
."~
: L. b .a ~ C
~J ~1 >~ ~ L
L L ~
O. D, ~ In Ul ~1 u C
~ C ~ X
O U O O ~1 .rl 0 ~r~ Il) r': a) .c .rl r~ 111 D~ tlll ~5 ~: C~
~ ~ n ~ ~ o (11 0 ~ ul 10 L ~ ~1) t9 ,,~ U~ u~ L. ul b 11~ L b L.
: c: ~ a u ~ 3 ~ ~ ~
~ ~:
Le A 2 3 4 7 7 ~:1 " ~". ., ,,. ., , ~' . ~ :
The ~estin~ of the lenses in an ani~al experiment on the eve of a rabbit re ~lts in a~ood bioco~patibility of the material, even after 21 day~ of ~ninterrupt~d wear.
For determining ~he in~rease in thi~kne~s, dry l~nses, rotated to completion, are stor~d for 6 days in a phvsiolo~ic~l salt solution at 20C. For determining the axtractable portions, the lense3 are washed after storage~
dried for 24 hours at 80C and rewei~hed~ In each case, tha wei~ht 10s5 is less than 0.1% by weight. The radii ~tability i5 about 0005 mm, the li~ht transmission with a layer thickness of 4.5 mm i5 about 90%.
Example 2 Monomer mix~ures of the ~ompositions listed in the follGwin~ Table 3 are filed into glass plate chambers with the measurements Z50 x 250 x 5 mm, provided with a sealin~
cord, under N2 after careful de~assing under vacuum, and exposed to radiation with a UV fluorescent lamp for 6 : 25 days. The plat~s are annealed for 24 hours at 80C and then for 2 hours at 14~ C. Unfinish~d product with a diameter of i2.5 m~ ar~ cut from ths plate6, which have b0en dialyzed for 6 days in deionized water. After drying ths unfinished products, contact lenses Df varyin~
thickness are produced therefrom by rotatin~ and polishin~.
.
~5 : Le A 23 477 : : :
~ ~ "'''' : :: .
.: ' ' ' ~ :
~ ' :
~ ""' ~ ' : ' " ~ . :
~n Lr) o ~ N
o~r)~IIooIo ~o W ~O
.Ln U- O
u) In ~ . . .
a In ~O o, o O`
_.
In Ln O
O o ~
U In _l ~ Ul I OI O
O`
o~ ., U~ Ln O
O ~ ~
U~ O O I O ~O
. U~ U~ o Ln In ~ ~r ~¢ U~ ~ I I O O I O U~
O
~O I
~a ,, .a--_I L
~ ~ In u ~ u ~
.1:! C~ u u ~ t, ~ ~ a x a ~
~ :~ k ~ o C: ~ _ Lu .1 0 :9 ~ ,1 rl a~
O
~ ~L ~1 o ~, :, ~ ~ ,,, ~ u ~ ~ o ~n ~ ~ o a ~
.,-1 ~ O L
1~ ~ L u o ~ c ~ ~ ~ m ~ ,~ b ta ~ .r~ 0 .C ~ C X ~ 1~ -1 ~ 0 L
E~ ~ E3 ~ .~ ~ o ~ r1 ~ O ~ 1 O I ~ N
, ~1:~ æ ~ N
Le A 2 3 4 7 7 ~: :
~. .. , -The measurement of the inner radii with average thickne~ses up to 0.08 mm r2sults in good raddi stabili~ies tvariations 0.1 mm). No streaks or cloudiness ~an be found during testing with the slit lamp. Light transmission 90% with a layer thickness of 4.7 mm. The portion which can be extracted with water is in all cases less than 0.1~/. by weight.
The animal experiment on ~he eye of a rabbit resul~
in good biological compatibility of the material with the eye, e~en after 21 day~ of uninterrup~ed ~ear.
;::
: 35 ; Le A 23 477 `' .
:' :
.
........... . -
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A contact lens, comprising a water-absorbing, cross-linked copolymer of an olefinically unsaturated monomer, in which the copolymer contains polymerized from 5 to 55% by weight of an N-vinyl amide of the general formula as monomer component, wherein R and R' represent, independently from each other, C1-C4-alkyl, with the proviso that R and R' cannot both be methyl.
2. A lens according to claim 1, in which the copolymer contains from 8 to 40% by weight of the N-vinyl amide.
3. A lens according to claim 2, in which the copolymer contains from 10 to 35% by weight of the N-vinyl amide.
4. A lens according to claim 1, 2 or 3, in which R
represents methyl.
represents methyl.
5. A lens according to claim 1, 2 or 3, in which R' represents methyl.
6. A lens according to claim 1 or 3 in which the copolymer contains an N-vinyl lactam, as further monomer component.
7. A lens according to claim 1 or 3 in which the copolymer contains N-vinyl pyrrolidone as further monomer component.
8. A lens according to claim 1 or 3 wherein the copolymer contains from 0.01 to 3% by weight of at least 2 olefinically unsaturated group-containing cross-linking agents.
9. A lens according to claim 1 or 3 wherein the copolymer contains from 0.1 to 2% by weight of at least 2 olefinically unsaturated group-containing cross-linking agents.
10. A lens according to claim 1 or 3 wherein the copolymer contains from 0.01 to 3% by weight of a combination of a (meth)acrylic acid ester cross-linking agent and a vinyl or allyl cross-linking agent.
11. A lens according to claim 1 or 3 wherein the copolymer contains from 0.01 to 3% by weight of a combination of a (meth)acrylic acid ester cross-linking agent and a vinyl or allyl cross-linking agent and the weight ratio of the cross-linking agents is from 1:3 to 3:1.
12. A lens according to claim 1 or 3 in which the copolymer contains a methacrylic acid ester as further monomer component.
13. A lens according to claim 1 or 3 in which the copolymer contains a methyl-, ethyl-, butyl- cyclohexyl-, benzyl- or phenyl methacrylate as further monomer component.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3445094.7 | 1984-12-11 | ||
| DE19843445094 DE3445094A1 (en) | 1984-12-11 | 1984-12-11 | SOFT CONTACT OPTICAL ITEMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1260193A true CA1260193A (en) | 1989-09-26 |
Family
ID=6252445
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000497140A Expired CA1260193A (en) | 1984-12-11 | 1985-12-09 | Soft contact-optical objects |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0184729B1 (en) |
| CN (1) | CN1005290B (en) |
| AT (1) | ATE45429T1 (en) |
| AU (1) | AU583554B2 (en) |
| BR (1) | BR8506182A (en) |
| CA (1) | CA1260193A (en) |
| DE (2) | DE3445094A1 (en) |
| NZ (1) | NZ214485A (en) |
| ZA (1) | ZA859420B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3823317A1 (en) * | 1988-07-09 | 1990-02-08 | Bayer Ag | BLANKS FOR CONTACT OPTICAL ITEMS |
| DE4423303C2 (en) * | 1994-07-02 | 2000-05-31 | Woehlk Contact Linsen Gmbh | Hydrophilic, crosslinked copolymers based on N-vinylformamide, process for their preparation and their use |
| US7468398B2 (en) | 1994-09-06 | 2008-12-23 | Ciba Vision Corporation | Extended wear ophthalmic lens |
| US5760100B1 (en) | 1994-09-06 | 2000-11-14 | Ciba Vision Corp | Extended wear ophthalmic lens |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1394056A (en) * | 1971-07-21 | 1975-05-14 | Nat Res Dev | Contact lenses |
| US4182802A (en) * | 1977-12-27 | 1980-01-08 | Samuel Loshaek | Hydrophilic polymers and contact lenses of high water content |
| DE2829652A1 (en) * | 1978-07-06 | 1980-01-17 | Hoechst Ag | METHOD FOR PRODUCING N-VINYLAMIDE POLYMERS |
| GB2087408B (en) * | 1980-11-04 | 1984-05-23 | Patel Pravin Gordhanbhai Da Co | Cross-linked hydrophilic polymers |
| JPS59195621A (en) * | 1983-04-22 | 1984-11-06 | Toyo Contact Lens Co Ltd | Soft contact lens |
| US4597700A (en) * | 1985-01-11 | 1986-07-01 | Mattel, Inc. | Record engraving apparatus |
-
1984
- 1984-12-11 DE DE19843445094 patent/DE3445094A1/en not_active Withdrawn
-
1985
- 1985-11-25 AU AU50344/85A patent/AU583554B2/en not_active Ceased
- 1985-11-29 AT AT85115139T patent/ATE45429T1/en not_active IP Right Cessation
- 1985-11-29 EP EP85115139A patent/EP0184729B1/en not_active Expired
- 1985-11-29 DE DE8585115139T patent/DE3572225D1/en not_active Expired
- 1985-12-05 CN CN85108859.7A patent/CN1005290B/en not_active Expired
- 1985-12-09 NZ NZ214485A patent/NZ214485A/en unknown
- 1985-12-09 CA CA000497140A patent/CA1260193A/en not_active Expired
- 1985-12-10 BR BR8506182A patent/BR8506182A/en not_active IP Right Cessation
- 1985-12-10 ZA ZA859420A patent/ZA859420B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BR8506182A (en) | 1986-08-26 |
| EP0184729A3 (en) | 1987-09-30 |
| EP0184729B1 (en) | 1989-08-09 |
| AU5034485A (en) | 1986-06-19 |
| CN85108859A (en) | 1986-06-10 |
| ATE45429T1 (en) | 1989-08-15 |
| NZ214485A (en) | 1988-10-28 |
| CN1005290B (en) | 1989-09-27 |
| DE3445094A1 (en) | 1986-06-19 |
| DE3572225D1 (en) | 1989-09-14 |
| EP0184729A2 (en) | 1986-06-18 |
| AU583554B2 (en) | 1989-05-04 |
| ZA859420B (en) | 1986-08-27 |
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