What is claimed is:
1. A contact lens, having:
a reduction in indentation force at an indentation depth of 400 nm, Δ(IF) 400nm , of about 50% or larger;
a polyquaternium-1 uptake of about 0.40 micrograms/lens or less; and
a water-break-up time of at least 10 seconds and/or a friction rating of about 2.0 or lower after simulated abrasion cycling treatment,
wherein the contact lens comprises an anterior surface, an opposite posterior surface, and a layered structural configuration, wherein the layered structural configuration comprises, in a direction from the anterior surface to the posterior surface, an anterior outer hydrogel layer, an inner layer of a lens material, and a posterior outer hydrogel layer,
wherein the inner layer is a preformed contact lens essentially made of a silicone hydrogel material.
2. The contact lens of claim 1 , wherein when Δ(IF) 400nm is determined in nano-indentation tests by using a probe having a tip radius of about 9.0±0.9 μm,
Δ
(
I
F
)
400
nm
=
1
-
(
I
F
)
t
2.12
·
E
′
-
0.38
in which (IF) t is the measured indentation force at an indentation depth of 400 nm of the contact lens and E′ is the bulk elastic modulus (E′) of the contact lens.
3. The contact lens of claim 1 , wherein when Δ(IF) 400nm is determined in microindentation tests by using 1 mm hemispherical borosilicate glass probe,
Δ
(
I
F
)
400
nm
=
1
-
(
I
F
)
t
1
3
.98
·
E
′
+
0.62
in which (IF) t is the measured indentation force at an indentation depth of 400 nm of the contact lens and E′ is the bulk elastic modulus (E′) of the contact lens.
4. The contact lens of claim 1 , wherein the contact lens has a polyquaternium-1 uptake of about 0.30 micrograms/lens or less.
5. The contact lens of claim 4 , wherein the silicone hydrogel material comprises (i) repeating units of at least one polysiloxane vinylic monomer and/or repeating units of at least one polysiloxane vinylic crosslinker and (ii) repeating units of at least one hydrophilic vinylic monomer.
6. The contact lens of claim 4 , wherein the silicone hydrogel material comprises repeating units of at least one hydrophilic N-vinyl amide monomer.
7. The contact lens of claim 4 , wherein the silicone hydrogel material comprises repeating units of at least one silicone-containing vinylic monomer having a bis(trialkylsilyloxy)alkylsilyl or tris(trialkylsilyloxy)silyl group.
8. The contact lens of claim 4 , wherein the silicone hydrogel material comprises repeating units of one or more blending vinylic monomers.
9. The contact lens of claim 4 , wherein the silicone hydrogel material comprises repeating units of one or more non-silicone vinylic crosslinking agents.
10. The contact lens of claim 4 , wherein the silicone hydrogel material has: an oxygen permeability of at least about 50 barrers; and/or an equilibrium water content of from about 10% to about 70% by weight.
11. The contact lens of claim 10 , wherein the silicone hydrogel material is not naturally wettable.
12. The contact lens of claim 10 , wherein the silicone hydrogel material is naturally wettable.
13. The contact lens of claim 10 , wherein the anterior and posterior outer hydrogel layers independent of each another are a crosslinked hydrophilic polymeric material which comprises at least 25% by mole of repeating monomeric units of at least one hydrophilic vinylic monomer selected from the group consisting of an alkyl (meth)acrylamide, N-2-dimethylaminoethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylate, a hydroxyl-containing acrylic monomer, a N-vinyl amide monomer, a methylene-containing pyrrolidone monomer, a (meth)acrylate monomer having a C 1 -C 4 alkoxyethoxy group, a vinyl ether monomer, an allyl ether monomer, and combinations thereof.
14. The contact lens of claim 10 , wherein the anterior and posterior outer hydrogel layers independent of each another are a crosslinked hydrophilic polymeric material which comprises at least 25% by mole of repeating monomeric units of at least one phosphrylcholine-containing vinylic monomer.
15. The contact lens of claim 10 , wherein the anterior and posterior outer hydrogel layers independent of each another are a crosslinked hydrophilic polymeric material which comprises poly(ethylene glycol) chains.
16. The contact lens of claim 11 , wherein the poly(ethylene glycol) chains are derived from: (1) a pol(ethylene glycol) having one sole functional group of —NH 2 , —SH or —COOH; (2) a poly(ethylene glycol) having two terminal functional groups selected from the group consisting of —NH 2 , —COOH, —SH, and combinations thereof; (3) a multi-arm poly(ethylene glycol) having one or more functional groups selected from the group consisting of —NH 2 , —COOH, —SH, and combinations thereof; or (4) combinations thereof.
17. The contact lens of claim 10 , wherein the anterior and posterior outer hydrogel layers independent of each another are substantially free of silicone.
18. The contact lens of claim 10 , wherein the contact lens further comprises two transition layers of a polymeric material, wherein each of the two transition layers is located bet