UV-ABSORBING EXTENDED-WEAR LENSES

VERRES-D'OPTIQUE POUR USAGE PROLONGE ET ABSORBEURS D'ULTRAVIOLETS

English Abstract

UV-ABSORBING EXTENDED-WEAR LENSES
Abstract of the Disclosure
There are provided extended-wear lenses formed by
polymerizing an organosilicon monomer, a fluoroorgano
monomer, a hydrophilic monomer, and a crosslinking agent.
The product includes a benzotriazole and/or a benzophenone
UV-absorbing agent and is is easily machinable to any
prescription, permitting continuous wear, with high oxygen
permeability and a receding contact angle of less than
45°C. The bulk of the monomer content is the fluoorgano
monomer and/or organosilicon monomer, which content is
limited to 40 parts by weight, with lesser amounts being
preferred.

Claims

-20-
THE EMBODIMENTS OF THE INVENTION IN WHICH AN
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. An oxygen-permeable UV-absorbing lens
comprising at least one UV-absorbing agent, the total
amount of W -absorbing agent present being in an amount
of from about 0.1 to about 20 percent by weight of a
polymer comprised of:
a) an organosilicon monomer system present in
an amount of from about 10 to about 40 percent by weight
based on the total weight of the UV-absorbing agent and
the monomers;
b) at least one hydrophilic monomer present
in an amount sufficient to provide in the resultant
polymer a contact angle of less than about 45°;
c) at least one crosslinking monomer, the
total of crosslinking monomer being present in an amount
up to about 5 percent by weight based on the total weight
of the monomers; and
d) the balance of the monomers comprising at
least one fluoroorgano monomer of the formula:
<IMG>
wherein M1 is hydrogen, alkyl, fluoroalkyl, alkyl
carboxy, carboxy ester, alkyl carboxy ester, fluorinated
carboxy ester, cyano, or phenyl, M is hydroxy alkyl,
alkyl ether, or hydroxy alkyl ether, a is as defined
above, c is from 0 to 4, and Y is a fluorocarbon group.

16751 -21-
2. An oxygen-permeable UV-absorbing lens as
claimed in claim 1 in which the UV-absorbing agent is
a non-reactive homopolymer or copolymer.
3. An oxygen-permeable UV-absorbing lens as
claimed in claim 2 in which the UV-absorbing homopolymer
or copolymer comprises an interpolymerized amount of at
least one UV-absorbing monomer selected from the group
consisting of a hydroxybenzophenone or benzotriazole of
the formula:
<IMG>
wherein R1 is hydrogen or methyl, a is 0 or 1, b is from
1 to about 4, and Z is:
<IMG> ;
<IMG>; or <IMG>

wherein R2 is hydrogen, alkyl or hydroxy and a phenyl
benzotriazole of the formula:
<IMG>
wherein R1 and R2 are as defined above, and R3 is H;
alkyl or hydroxyl.
4. An oxygen-permeable lens comprising an
interpolymerized amount of:
a) an organosilicon monomer system including
monomers of the formula:
<IMG>
wherein R1 is hydrogen or methyl, a is 0 or 1, b is from
1 to about 4, and X is an organosilicon moiety containing
up to about 16 silicon atoms, the total organosilicon
monomer being present in an amount of from about 10 to
about 35 percent by weight based on the total weight of
the monomers;
b) at least one UV-absorbing monomer selected
from the group consisting of a hydroxybenzophenone or
benzotriazole of the formula:
<IMG>

-23-
wherein R1 is hydrogen or alkyl, a is 0 or 1, b is from 1
to about 4, and Z is:
<IMG>
-23-
wherein R2 is hydrogen, alkyl or hydroxy and a phenyl
benzotriazole of the formula:
<IMG> ;
<IMG> ; or <IMG>
wherein R1 and R2 are as defined above, and R3 is H;
alkyl or hydroxyl, said UV-absorbing monomer being
present in an interpolymerized amount of from about 0.1
to about 20 percent by weight based on the total weight
of the monomers;
c) at least one hydrophilic monomer present
in an amount sufficient to provide in the resultant
polymer a contact angle of less than about 45°;
d) at least one crosslinking monomer, the
total of crosslinking monomer being present in an amount
up to about 5 percent by weight based on the total weight
of the monomers; and

-24-
e) the balance of the monomers comprising at
least one fluoroorgano monomer of the formula:
<IMG>
wherein M1 is hydrogen, alkyl, fluoroalkyl, alkyl
carboxy, carboxy ester, alkyl carboxy ester, fluorinated
carboxy ester, fluorinated alkyl carboxy ester, cyano, or
phenyl, M is hydroxy alkyl, alkyl ether, or hydroxy alkyl
ether, a is as defined above, c is from 0 to 4, and Y is
a fluorocarbon group, said lens having a Shore D hardness
greater than about 78.
5. An oxygen-permeable UV-absorbing lens as
claimed in claim 4 in which the organosilicon monomer is
present in a concentration of from about 20 to about 30
percent by weight based on the total weight of
interpolymerized monomers.
6. An oxygen-permeable UV-absorbing lens as
claimed in claim 1, 2 or 3, in which the lens has oxygen
permeability of at least about 15 x 10-11.
7. An oxygen-permeable UV-absorbing lens as
claimed in claim 1, 2 or 3, in which the oxygen
permeability is at least about 50 x 10-11.

16751 -25-
8. An oxygen-permeable UV-absorbing lens as
claimed in claim 4 in which the organosilicon monomers
are selected from compounds of the formula:
<IMG>
wherein X' is <IMG> or <IMG>
wherein each of R4 and R5 is independently a C1-C5 alkyl,
phenyl, hydroxyl, or -O-Si(CH3)3, and each of R6, R7
and R8 is independently selected from C1-C5 alkyl;
-CH2=CH2; phenyl; hydroxyl; -CH2OH;
<IMG> ; <IMG> ;
<IMG> ; O-Si-[OSi(CH3)3]3 ; or
<IMG>
wherein R1 is hydrogen or alkyl, a is 0 or 1, and b

16751 -26-
9. An oxygen-permeable UV-absorbing lens as claimed
in claim 1 in which the organosilicon monomer is selected
from tris(trimethylsiloxy)-?-methacryloxypropylsilane,
1,3-bis-(?-methacryloxypropyl-)1,1,3,3-tetra(trimethyl-
siloxy)disiloxane and mixtures thereof.
10. An oxygen-permeable UV-absorbing lens as claimed
in claim 4 in which the organosilicon monomer is selected
from tris(trimethylsiloxy)-?-methacryloxypropylsilane,
1,3-bis-(?-methacryloxypropyl-)1,1,3,3-tetra(trimethyl-
siloxy)disiloxane and mixtures thereof.
11. An oxygen-permeable UV-absorbing lens as claimed
in claim 1 in which the fluoorgano monomer is 2,2,2
-trifluoroethylmethacrylate, hexafluorobutylmethacrylate,
hexafluoroisopropylmethacrylate and mixtures thereof.
12. An oxygen-permeable UV-absorbing lens as claimed
in claim 9 in which the fluoorgano monomer is 2,2,2
-trifluoroethylmethacrylate, hexafluorobutylmethacrylate,
hexafluoroisopropylmethacrylate and mixtures thereof.
13. An oxygen-permeable UV-absorbing lens as claimed
in claim 4 in which the fluoorgano monomer is 2,2,2
-trifluoroethylmethacrylate, hexafluorobutylmethacrylate,
hexafluoroisopropylmethacrylate and mixtures thereof.
14. An oxygen-permeable UV-absorbing lens as claimed
in claim 10 in which the fluoorgano monomer is 2,2,2
-trifluoroethylmethacrylate, hexafluorobutylmethacrylate,
hexafluoroisopropylmethacrylate and mixtures thereof.

16751 -27-
15. An oxygen-permeable UV-absorbing lens as claimed
in claim 1 in which the hydrophilic monomer is methacrylic
acid.
16. An oxygen-permeable UV-absorbing lens as claimed
in claim 5 in which the hydrophilic monomer is methacrylic
acid.
17. An oxygen-permeable UV-absorbing lens as
claimed in claim 14 in which the hydrophilic monomer is
methacrylic acid.
18. An oxygen-permeable UV-absorbing lens as claimed
in claim 1 in which the UV-absorbing agent comprises a
monomer selected from the group consisting of
2-hydroxy-4-(2-methacryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-acryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-hydroxy-3-methacryloxypropyl)benzophenone,
2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, and
mixtures thereof.
19. An oxygen-permeable UV-absorbing lens as claimed
in claim 3 in which the UV-absorbing agent comprises a
monomer selected from the group consisting of
2-hydroxy-4-(2-methacryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-acryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-hydroxy-3-methacryloxypropyl)benzophenone,
2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, and
mixtures thereof.

16751 -28-
20. An oxygen-permeablle UV-absorbing lens as claimed
in claim 4 in which the UV-absorbing agent comprises a
monomer selected from the group consisting of
2-hydroxy-4-(2-methacryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-acryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-hydroxy-3-methacryloxypropyl)benzophenone,
2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, and
mixtures thereof.
21. An oxygen-permeable UV-absorbing lens as claimed
in claim 14 in which the UV-absorbing agent comprises a
monomer selected from the group consisting of
2-hydroxy-4-(2-methacryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-acryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-hydroxy-3-methacryloxypropyl)benzophenone,
2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, and
mixtures thereof.
22. An oxygen-permeable lens comprising an
interpolymerized amount of:
a) an organosilicon monomer system including
the formula:
<IMG>
wherein R1 is hydrogen or methyl, a is 0 or 1, b is from
1 to about 4, and X is an organosilicon moiety containing
up to ahout 16 silicon atoms, the total organosilicon
monomer heing present in an amount of from about 10 to
about 35 percent by weight based on the total weight of
the monomers;

16751 -29-
Claim 22, continued. . .
b) from 0 to about 10 percent by weight of the
monomers of a UV-absorbing monomer selected from the
group consisting of a hydroxybenzophenone or
benzotriazole of the formula:
<IMG>
wherein R1, a and b are as defined ahove, d is 1 or 2,
and Z is:
<IMG> ;
<IMG> ; or <IMG>
wherein R2 is hydrogen, alkyl or hydroxy and a phenyl
benzotriazole of the formula:
<IMG>
wherein R1 and R2 are as defined above, and R3 is H;
alkyl, preferably a C1-C10 alkyl, or hydroxyl, said UV-
absorbing monomer beint present in an interpolymerized
amount of from ahout 2 to about 10 percent by weight
based on the total weight of the monomers;

16751 -30-
Claim 22, continued. . .
c) methacrylic acid in an amount sufficient to
provide in the resultant polymer a contact angle of
less than about 45°;
d) at least one crosslinking monomer, the total
of crosslinking monomers being present in a concentration
of from about 0.1 to about 2 percent by weight based on
the total weight of the monomers; and
e) the balance of the monomers comprising at
least one fluoroorgano monomer of the formula:
<IMG>
wherein M1 is hydrogen, alkyl, fluoroalkyl, alkyl
carboxy, carboxy ester, alkyl carboxy ester,
fluorinated carboxy ester, cyano, or phenyl, M is
hydroxy alkyl, alkyl ether, or hydroxy alkyl ether,
a is as defined above, c is from 0 to 4, and Y is a
fluorocarbon group preferably containing from about 2
to about 21 fluorine atoms, said lens having a Shore D
hardness greater than about 78 and an oxygen permeability
of at least 15 x 10-11(cm2/sec.)(m1 O2/ml x mm Hg).
23. An oxygen-permeable UV-absorbing lens as claimed
in claim 22 in which the organosilicon monomer is present
in a concentration of from about 20 to about 30 percent
by weight based on the total weight of interpolymerized
monomers.

- 31 -
24. An oxygen-permeable UV-absorbing lens as
claimed in claim 22 in which the organosilicon monomer is
selected from the group consisting of
tris(trimethylsiloxy)-methacryloxypropylsilane, 1,3-bis-
(?-methacryloxypropyl)-1,1,3,3-tetra(-trimethyl-
siloxy)disiloxane and mixtures thereof, and in which the
hydroxyorganosilicon monomer is hydroxy-di(trimethyl-
siloxy)silylpropylmethacrylate.
25. An oxygen-permeable UV-absorbing lens as
claimed in claim 20 in which the fluoroorgano monomer is
2,2,2-trifluoroethylmethacrylate, hexafluorobutyl-
methacrylate, hexafluoroisopropylmethacrylate and
mixtures thereof.
26. An oxygen-permeable UV-absorbing lens as
claimea in claim 25 in which the UV-absorbing monomer is
selected from the group consisting of
2-hydroxy-4-(2-methacryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-acryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-hydroxy-3-methacryloxypropyl)benzophenone,
2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, and
mixtures thereof.
27. An oxygen-permeable UV-absorbing lens as
claimed in claim 1 wherein the fluorocarbon group is from
about 2 to about 31 fluorine atoms.
28. An oxygen-permeable UV-absorbing lens as
claimed in claim 3 wherein R3 is a C1-C10 alkyl.
29. An oxygen-permeable lens as claimed in claim 4
wherein R3 is a C1-C10 alkyl.

-32-
30. An oxygen-permeable lens as claimed in claim 4
wherein the fluorocarbon group is from about 2 to about
20 fluorine atoms.

Description

~L2~9~2
C27~:16751:JPG:477 -1-
UV-ABSORBING EXTENDED-WEAR LENSES
Background of the Invention
The present invention is Airected to ~ye-compatible
lenses, particularly hard contact lenses having excellent
oxygen permeability and wettahility.
Contact lenses presently on the market are classi-
fied into two large ~roups: soft contact lenses and h~rd
contact lenses. Hard contact lenses ~re better able than
soft contact lenses to retain visual ~haracteristics, but
are less comfortable. The art has sought to increase
oxygen per~eability of hard contact lenses, to extend the
length o time they can ~e worn without causing corneal
damage or discomort.
One propos~d solution has 6een the formation of a
copolymer of methyl methacrylat~ and a siloxane methacry-
3 late compound. This solution has been less than satis-
factory, since the ~enses offere~ are not as hard, rigid,
nor wetta~le as lenses formed from polymethyl methacryl-
ate. In addition, such lenses are fragile and have poor
mechanical processability.
`
~ ..

~127~4Z
16751 -2-
1 The object of the present invention is to overcome
the deficiencies in the state of the art by offering
lenses having a high degree of oxygen permeability,
excellent wettability, and, if desired, ultraviolet
absorption. The primary benefit of UV absorptivity is
the resistance to user development of cataracts.
Summary of the Invention
The present invention is directed to oxygen-permeable
UV-absorhing lenses comprising copolymers of ~t least one
organosilicon monomer which is preferably an organosilane
or an organosiloxane of the general formula:
CH2 = C-Rl OH
l l
Coo-(cH2-cH-cH2o)a-lcH2)b-x (1)
wherein Rl is hydrogen or methyl, a is 0 or 1, b is from
1 to about 4, an~ X is an organosilicon moiety containing
up to about 16 silicon atoms;
CH2 = C - Ml
I (2)
COO--~M)a--~CH2)c~Y
wherein Ml i.s hydrogen, alkyl, fluoroalkyl, alkyl car-
boxy, carboxy ester, alkyl carboxy ester, fluorinated
carboxy ester, fluorinat~d alkyl carboxy ester, cyano, or
phenyl, M is hydroxy alkyl, alkyl ether, or hydroxy alkyl
ether, a is as defined above, c is from 0 to 4, an~ Y is
a fluorocarbon group, preferably containing from about 2
to about 21 fluorine atoms.

14i~
16751 -3-
1 At least one hydrophilic monomer is included,
preferably an unsaturated carboxylic acid capable of
inducing wettability, and is present in an amount suffi-
cient to provide in the resultant polymer a receding
contact angle of about 45 or less. Methacrylic acid is
preferred. At least one UV-absorbing agent is included.
The UV-absorbing agent may be a UV-absorbing monomer,
preferably hydroxybenzophenone or a benzotriazole
compound of the formula:
( CH2 = I-R
Coo-(cH2-cHoH-cH2o)a- (C~2)b ~ Z (3
~ d
wherein Rl, a and b are as defined above, d is 1 or 2,
and Z is:
OH O OH
20 ~2 ~ C ~ o _ ;
DH
~ ~ ~ ; or ~N~
R2
wherein R2 is hydrogen, alkyl or hydroxy. Alternately
or in addition. the UV-absor~ing monomer may be a ben~o-
triazole of the formula:
OH
3 ~ N ~ 2
C~-- CH2
3S ~1

~L27~ 4Z
16751 -4-
l wherein Rl and R2 are as defined above, and R3 is H or
alkyl, preferably a Cl-Clo alkyl, provided to induce
UV absorbance to the lens.
The UV-absorbing agentlmay also be non-polymerizable
homopolymers and copolymers, preferably containing UV-
absorbing units which are added to the monomer system
that undergoes polymerization and which become physically
entrained in the formed lens.
In the polymerized state, the UV-absorbing monomers
act as a UV filter or screen capable ~f preventing UV
transmission to the eye. It is important that in this
regard most of the complications associated with cornea
aphakia and retina problems can be prevented. In addi-
tion, the phenolic moiety enhances wettability of the
lens. Moreover, being compatible with the other monomers,
the UV-absorbing monomers are readily copolymerized and
permanently retained in the polymer chain. Migration to
the polymer surface and leaching are avoided.
A final component is a crosslinking monomer which
is a crosslinking agent. preferably a silicon monomer,
present in an amount up to about 5, preferably up to
about 2, percent by weight.
lt has been found that the total organosilicon-
monomer content of the polymer may range from about 10 to
ahout 40 percent by weight, preferably from about 10 to
about 35 percent by weight, more preferahly 30 percent by
weight. The hydrophilic monomer may be present in an
amount of from ~hout 1 to ahout 15 percent by weight,
preferably from ahout 2 to about 10 percent by weight.
The UV agent may be present in an amount of from ahout
0.1 to about 2n percent, preferably from about 2 to ahout
10 percent by weight, and the crosslinking monomer may
be present in an amount up to about 2 percent by weight.
All percentages are hased on the total weight of the
UV-absorhing agent and the monnmers. The balance of the

1~914~
16751 -5-
1 monomer system may be solely the fluoroorgano monomers.
It is desired that the lens have a Shore D hardness
greater than about 78, preferably from about 80 to about
85. There may be desirably included other monomers such
as acrylates, methacrylates, itaconic esters, styrenes,
fluorinated styrenes, alkyl styrenes, fluorinated alkyl
styrenes, and the like, present in a concentration of up
to about 50 percent by weight of the concentration of the
fluoroorgano monomer, typically in a concentration of up
to about 5 percent by weight based on the total weight of
the UV-absorbing agent and the monomers. Such monomers
are used to modify properties such as hardness, machina
bility, wettability, oxygen permeability, and the like.
It is desired to provide an oxygen permeability at
15 35C greater than 50 x 10 11(cm2/sec.)~ml O2/ml x mm Hg).
When using low-cost fluoroorgano compounds such as
2,2,2-trifluoroethylmethacrylate, the organosilicon
content of the monomer system must be high, typically in
; the range of from 25 percent to 30 percent or more by
weight based on the total weight of the UV-absorbing
agent and the monomers. Organosilicon monomer content
can be advantageously reduced, however, by inclusion of
high-performance fluoroorganomonomers such as hexafluoro-
isopropylmethacrylate.

1~7~4Z
16751 -6-
Detailed Descri~tion
The present invention is directed to eye-compatible,
i.e., ocular-compatible, lenses, in particular, hard
contact lenses, formed of an interpolymeriz~d amount of
at least one organosilicon monomer, at least one fluoro-
organo compound, at least one monomeric unsaturated
carboxylic-acid wetting agent, and a UV-absorbing agent
which is preferably a monomer of benzotriazole and/or
henzophenone, and at least one crosslinking monomer.
Other reactive monomers such as acrylates, methacrylates,
itaconic esters, styrenes, fluorinated styrenes, alkyl
styrenes, fluorinated alkyl styrenes, and the like, may
be included as part of the polymerizable composition, to
achieve a lens of desired hardness, wettability, oxygen
permeahility, machinability, and the like.
The organosilicon monomers which may be used in
accordance with the instant invention include organo-
silanes and/or organosiloxanes of the general formula:
CH2 = IC-Rl
Coo-(cH2-cHoH-cH2o)a-~cH2)b-~ (1)
wherein Rl is hydrogen or methyl, a is 0 or 1, b is from
1 to about 4, and X is an organosilicon moiety containing
up to about 26 silicon atoms.
Preferred organosilicon compounds are acrylates and
methacrylates of the general formula:
CH,2 = IC-Rl
C~o(-cH2-cHoH-cH2-o-)a~~cH2)~-x (2)

79~L4Z
16751 -7_
R4 l6 lR6
wherein X' is -7i-(CH2)b-fi-R7 or fi 7
R5 R8 R8
each of R4 and Rs is independently a Cl-Cs alkyl, phenyl,
or -O-Si(CH3)3, and each of R6, R7 and R8 is independently
selected from Cl-Cs alkyl; -CH2=CH2; phenyl; -CH2OH;
ICH3IH3
-o-Si-O-Si(CH3)3 ; -O-f i-OH
CH3 CH3
/ O-Si(CH3)3
-O-SiCH3 ; o-si- [osi ( CH3)3]3 ; or
o-si ( CH3)3
CH2 = C-Rl
I
Coo-(cH2-cHoH-cH2-o-)a~~cH2)b- '
wherein Rl, a, and b are as defined above.
The representative monomers included are:
tris(trimethylsiloxy)silylpropylmethacrylate,
1,3-bis(~-methacryloxypropyl)-1,1,3,3-tetra(trimethyl-
siloxy)disiloxane,
vinyl di(trimethylsiloxy)silylpropylmethacrylate,
3 pentamethyldisiloxy-~-methacryloxypropylsilane,
trimethylsilylpropylmethacrylate,
methyl di(trimethylsiloxy)silylpropylmethacrylate, and
tris(trimethylsiloxy)silylpropylglycerolmethacrylate, and
the like. Tris(trimethylsiloxy)-~-methacryloxypropyl-
: 35

1~79~2
16751 -~B-
1 silane is presently preferred. Another important monomer
is 1,3-bis~ methacryloxypropyl)-1,1,3,3-tetra(trimethyl-
siloxy)disiloxane, as it ~er~es as a ceosslinking ~gent
without ~acrificing oxygen permeability. ~hen u~ed for
this purpose, concentration ~ay vary from about 0.1 to
about 2 parts by weisht based on the total weight of the
reactants.
Other useful organosilicon monomers are disclosed in
U.S. Patents 4,1~2,508 to Ellis; 4,153,641 to Deichert et
al; 4,189,546 to Deichert et al: and 4,463,149 to Ellis.
While concentrations of organo~ilicon monomers may
range from ahout 10 to abvut 40 parts by weight based on
the total weight of the UV-absorbing agent ~nd the mono-
mers, the preferred range is from about 10 to about 35,
more preferably from about 20 t~ about 30 parts by weight.
Oxygen permeability (all other factors being constant)
will increase with an increase in organosilicon monomer
content. At higher levels, the lens becomes more diffi-
cult to machine, reguiring the inclusion of ~onomers as
part of the monomer system, as mentioned above, to yield
a lens having a Shore D hardness greater than about 78,~
preferably from about 80 to about 85.
The fluoroorgano monomers utile in the practice of
the instant invention are generally compounds of the
formula:
CH2 = C - Ml
I (3)
COO-(M)a-(C~2)c~y
wherein Ml is hydrogen, alkyl, fluoroalkyl, alkyl car-
boxy, carh~xy ester, alkyl carboxy ester, fluorinated
carhoxy ester, fluorinated alkyl carboxy es~er, cyano, or
phenyl, M is hydroxy alkyl, alkyl ether, or hydroxy alkyl
~ ,.

~279~42
l6751 -9-
l ether, a is as defined above, c is from O to 4, and Y is
a fluorocarbon group, preferably containing from about 2
to about 21 fluorine atoms. Preferably, Y has the
formula:
CnF2n+l lDr CnF2nW-
Illustrative of fluoroorgano monomers are:
2,2,2-trifluoroethylmethacrylate,
hexafluorobutylmethacrylate,
hexafluoroisopropylmethacrylate,
pentafluoro-n-propylmethacrylate, and the like.
Trifluoroisopropylmethacrylate is the preferred monomer
for oxygen permeability, with 2,2,2-trifluoroethyl-
methacrylate being preferred for cost. Perfluoro or
fluorinated styrenes may also be used.
Hydrophilic monomers are include~ in the composition
to induce wettability. They preferably comprise an
unsaturated carhoxylic acid, most preferably methacrylic
acid, for compatability of monomers and wearer comfort.
Acrylic acid is functional but less desirable. Other
monomers such as 2-hydroxyethylmethacrylate and the like
may be used. Concentration may be from ahout 0.1 to
about 15 or more percent by weight, preferably from about
2 to about lO percent hy weight based on the total weight
of the UV-absorbing agent and the monomers.
The amount of hydrophilic monomer present depends on
the amount of UV-ahsorbing agent, as described below, is
employed, as the latter also has the capahility of being
a hydrophilic agent. Whether in monomeric or in poly-
meric form, its concentration may range from ahout 0.1 toabout 20 percent hy weight, preferably from about 2 to
about 10 percent hy weight based on the total weight of
the monomers. The ~V absorhing agents used herein are
preferably in a polymerized form and cooperate with the

~2~ 4%
16751 -10-
1 hydrophilic monomer to induce wettability and antiseptic-
ability, i.~., self-sterilizable, in consequence of
hydroxy-substituted benzene moieties. In the polymerized
state, the UV absorbers absorb in the range of from about
30nnm to ahout 450nm, preferably with no less than about
70% UV radiation at 370nm. Preferred UV-absorbing agents
are, or are formed of, monomers of the formula:
~H2 = C-Rl
Coo-(cH2-cHoH-cH2-o-)a~(cH2-)b ~ Z (4)
~ d
wherein Rl is hydrogen or methyl, a is 0 or 1, b is from
about 1 to about 4, d is l or 2, and Z is:
OH O OH
R2 ~ C ~ o _ ;
ON
C ~ ~ N~ D--
wherein R2 is hydrogen; an alkyl, preferably a Cl-Cs
alkyl or hydroxyl, and c is 1 or 2. In the alternative or
in addition, there may be employed a phenyl benzotriazole
of the formula:
R3~N~ ~ R2
C\- CH2
n

lZ7~4~
16751
1 wherein Rl and R2 are as defined above, preferably a Cl-
Clo alkyl, and R3 is H, alkyl, preferably a Cl-Clo alkyl,
or hydroxyl.
Preferred ~V absorbers include:
2-hydroxy-4-(2-methacryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-acryloyloxyethoxy)benzophenone,
2-hydroxy-4-(2-hydroxy-3-methacryloxypropyl)benzophenone,
2-(2-hydroxy-5-vinylphenyl)-2H-benzotriazole, and the
like.
The UV-absorbing agents are either part of the mono-
mer system or are high-molecular-weight, non-polymerizable
homopolymers or copolymers preferably containing such
monomers as described above or other ~V-absorbing units.
They are reacted as such with the polymerizable monomer
system and are entrained in the polymerization product.
The hard contact lenses of the instant invention are
formulated to have high oxygen permeability (Dk) of at
least about 15 and preferably greater than 50, as
expressed in units of 10 11(cm2/sec.)(ml O2/ml x mm Hg)
; 20 and as determined at 35C. Values are achieved using high
concentrations of the organosilicon monomer and/or
selection of the fluoroorgano monomer. With compositions
of high organosilicon-monomer content there are displayed
increased brittleness and a reduction in capability to
undergo machining. At least one crosslinking agent, such
as a multi-functional organosilicon monomer, a fluoro-
organo monomer, or other modifying monomer, is employed
in an amount sufficient to control hardness of the lens
in the range of Shore D hardness of from about 80 to
about 85. A highly multi-functional organosilicon monomer
is preferred, as it does not interfere with oxygen permea-
bility. Other crosslinking agents which may be used
include ethylene glycol dimethacrylate, ethylene glycol
diacrylate, diethylene glycol dimethacrylate, diethylene
glycol diacrylate, and the like.

~27~142
16751 -12-
1 Lens formation is by free radical polymerization
such as azobisisobutyronitrile (AIBN) and peroxide
catalysts under conditions set forth in U.S. Patent
3,808,179. Colorants
and the like may be added prior to monomer polymerization.
It is preferred to form the lens base in sheet form
between layers of a non-adherent surface. The sheet is
cut into smaller lense precursors from which the lens is
ground to user specifications. Spin-casting, as described
for instance in U.S. Patent 3,408,429, may also be used.
Without limiting, the following Examples are illus-
trative of the instant invention~ Wi~h referencs to the
Examples, properties of the contact lenses were measured
according to the following methods.
Oky~en permeability values were determined using a
test method developed by Dr. Irving Fatt of Berkeley,
California, and disclosed in the paper, entitled: "Oxygen
Transmissibility ~nd Permeability of Gas Permeable Hard
Contact Lenses and Materials" by Irving Fatt, Ph.D.,
International Contact Lens Clinic, Vol. 11, No. 3, March
-
1984. The instrument was ~ polarographic cell with
a curved surface for finished lenses, polarographic
amplifier, recorder and a constant temperature chamber
equipped wit~ a temparature control unit. The measurements
were made at 35C and the units of oxygen permeability
(Dk) are (cm2/sec.)(ml 02/ml x mm Hg).
The water wettability of the contact lense material
was determined by the sesile drop method using a Rame-
Hart goniometer with an environmental chamber. Both the
advancing and the receding contact angles were determined.
m e hardness was measured as Shore D at 22C using a
hardness tester, and percent light transmission was
measured using a recording spectrophotometerO
The absorption spectra of the copolymer were
determined on a "Perkin Elmer" UV-Vis spectrophctometer
using 0.1-0.15mm-thin optically polished discs. The

9142
16751 -13- ~
1 amount of materials extractable from the lenses were
; evaluated by first storing them in a saline solution for
10 days at 35C. The lenses were then rinsed with
distilled water, dried, weighed, and placed in stoppered,
5 25cc volumetric flasks, again containing saline as the
extracting medium. The saline was analyzed daily for its
extracted ultraviolet absorber by placing 4cc of the
extract in a spectrophotometer cell and determining the
absorption at 320nm. The absorption values were compared
against the calibration curve made for the pure ultravio-
let absorber. Extractables can also be determined by the
Soxhlet extraction method, using water as the solvent~
The amount of extractables was determined only for a few
of the materials in the Examples. Based on 0.04gr average
lens weight, extractables'were found, on the average, to
be less than 1 x 10~4mc grams/lens/day.
For a few selected copolymer materials, the leacha-
bility-diffusibility was evaluated by cytotoxicity assay-
agar overlay method.
The assay is based on the method described by Guess,
W.L., Rosenbluth, S.A., Schmidt, B., and Autian, J., in
nAgar Diffusion Method for Toxicity Screening of Plastics
on Cultured Cell Monolayers", J. Pharm. Sci. 54:1545-1547,
1965, and is designed '-
to detect the response of a mammalian monolayer cell
culture to readily diffusible components from materials
or test solutions applied to the surface of an agar layer
overlaying the monolayer.
The r~sponse of the cell monolayer is evaluated,
with respect to the discoloration of the red-stained mono-
layer, under and aro~nd the sample when the petri dish isviewed against a white background. Loss of color of the
stained cells is considered to be a physiologically sig-
nificant reaction of the cells. The extent of discolora-
tion is confirmed by examination of the monolayer on aninverted microscope, and the extent of lysis of the cells
within the discoloration zone is estimated. Typically,

~.~279~D~Z
16751 -14-
1 discoloration of cells precedes lysis, as manifested by a
region and a region showing lysis. A sample is reported
as "cytotoxic" only if lysis is observed.
_xample 1
An oxygen-permea~le copolymer was prepared from a
mixture of 25 parts by weight of tris(trimethylsiloxy-
)-~-methacryloxypropylsilane, 65 parts by weight of
trifluoroethylmethacrylate, 5 parts by weight of
2-hydroxy-4-(2-acryloxyethoxy)benzophenone, 5 parts by
weight of methacrylic acid, and 0.02 parts by weight of
AIBN.
The mixture was homogenized, degassed and placed in
a polymerization cell made of two glass plates separated
by a seal and held together hy spring clamps. After
filling, the cell was purged with nitrogen, sealed and
placed in a circulating water bath at 6noc for 10 hours.
After the initial polymerization period, the cell was
heated at ~0C for 3 hours, 100C for one hour, and then
Z allowed to cool to room temperature. The clamps were
then removed and the transparent sheet heated for 2 hours
at 100C. The plastic sheet, about 14-inch in thickness,
was cut into squares, then formed to discs which were
used to prepare corneal contact lenses using conventional
hard-contact-lens-making equipment. The properties of
this lens material are shown in Table I.
TA~LE I
_ _
3 Properties Example 1
Oxygen Permea~ility 54
Contact Angle 20
Light Transmission Trans~arent
Hardness 84
3S Cytotoxicity Assay Negative

~2~42
l6751 -15-
Examples 2-22 and Control A
Following the procedure of Example 1, additional
polymers were formed for lens use. The composition, in
parts-by-weight of reactants and lens properties, are
shown in Table II. The Control does not include a
hy~rophilic monomer nor a UV-absorbing monomer.

1~79~42
16751 -16-
o m ~r r ~ v
~' N Itl C Ir~ N ~1 1~
o ¦ o~--~ o Ul C ~ ~ Z
o~ I o Irl ou) o 11~ I Z
01 ~-- U~ O h'7 ~ N 0
l o N .t:
, _ ¦ 2 ~ ~ ~ ~ N 0
~ V ~ O 1~ 0 u~ ' N
15 ~ o u~
l N¦u~ o u~ o 0 _ _ E~ ~ z
~ ? ~ ~ D

~IL2,'7~L42
1 6 7 5 1 - 1 7-
G O ~ r) 0
~ I c~ I` ~ o 1~1 ~ o P ~r
~ ¦ ~ E o N N X
~ ¦ N .D 0 ~ O U~ P~ r ~ ~
ol¦ o E u~ ~ o ,n ~ ~ ~ ~c
10~ s --I N ~ q o ~r~ N N
~ ~ _ ~
-- ~¦ ~ ~ o u~ o ~1` ~ 0 ~ z
~¦ ¦ u, u~ o u~ N _ ~D
1~ N U~ U 0 I` E'~ N
20 ~I N --¦ ~ ~ n N
ID
~ j;.d.
~b~
3 ~ L N ~ ~ N ~ N ~ Z

~27~L42
16751 -18-
Example 23
Following the procedure of Examples 1-14, lenses
were made from a polymer formed by polymerizing 24 parts
by weight tris(trimethylsiloxy)silylpropylmethacrylate,
1 part by weight 1,3 bis~-methacryloxypropyl)-1,1,3,3
-tetra(trimethylsiloxy)disiloxane, 5 parts by weight
methacrylic acid, 5 parts by weight 2-hydroxy-4-(2-acryl-
oxyethoxy)benzophenone, and 65 parts by weight 2,2,2
-trifluoroethylmethacrylate. The lenses formed were
transparent, with an oxygen permeability of 54 x 10-11
(cm2/sec.)(ml 02/ml x mm Hg) and a receding contact angle of
about 20~C.
Two evaluations were made. In one, over 300 persons
wore fitted lenses during normal waking hours. Another
group wore the lenses 24 hours per day. Both groups wore
the lenses for protracted periods of time without
discomfort. In another study, patients unable to wear
soft lenses, or any other commercial oxygen-permeable
lens, were able to wear the lenses with complete comfort.
Clinical reports from participating doctors suggest that
the lenses performed better and were safer than any other
lens used, and also suggest a potential for years of
trouble-free wear. Patients confirmed excellent wetta-
bility, no forming of film or deposit, and no sensitivity
to glare. These results were unexpected, because silicon
compounds do not wet well and are not durable.
Example 24
Following the procedure of Examples 1-14, an oxygen-
permeable copolymer was prepared from a mixture of 22
parts by weight tris(trimethylsiloxy)-~-methacryloxy-
propylsilane, 2.7 parts by weight hydroxy-di(trimethyl-
siloxy)sily:Lpropylmethacrylate, 0.3 parts by weight
1,3 bis(~-methacryloxypropyl)-1,1,3,3-tetra(trimethyl-

~:7~142
16751 -19- -
I siloxy)disiloxane, 65 parts by weight trifluoroethyl-
methacrylate, 5 parts by weight 2-hydroxy-4-(2-acryloxy-
ethoxy)henzophenone, ~ parts by weight methacrylic acid,
and 0.02 parts by weight AIBN. The properties of this
lens material are shown in Table III.
TA~LE III
Oxygen Permeability 54
Contact Angle 20
Light Transmission Transparent
Hardness 84
: 15 Cytotoxicity Assay Negative