Silicone hydrogel lenses with water-rich surfaces
View Patent ↗The invention is related to a hydrated silicone hydrogel contact lens having a layered structural configuration: a lower water content silicone hydrogel core (or bulk material) completely covered with a layer of a higher water content hydrogel totally or substantially free of silicone. A hydrated silicone hydrogel contact lens of the invention possesses high oxygen permeability for maintaining the corneal health and a soft, water-rich, lubricious surface for wearing comfort.
1. A hydrated silicone hydrogel contact lens, comprising:
an anterior surface and an opposite posterior surface; and
a layered structural configuration from the anterior surface to the posterior surface,
wherein the layered structural configuration includes an anterior outer hydrogel layer, an inner layer of a silicone hydrogel material, and a posterior outer hydrogel layer,
wherein the inner layer is a preformed silicone hydrogel contact lens made from a silicone hydrogel lens formulation comprising a hydrophilic vinylic monomer and a polysiloxane-containing vinylic monomer or macromer,
wherein the inner layer of the silicone hydrogel material has an oxygen permeability of at least about 50 Barrers, a first water content WC SiHy of from about 10% to about 65% by weight, and an elastic modulus of from about 0.3 MPa to about 1.8 MPa,
wherein the anterior and posterior outer hydrogel layers are substantially uniform in thickness and merge at the peripheral edge of the contact lens to completely enclose the inner layer of the silicone hydrogel material,
wherein the anterior and posterior outer hydrogel layers independent of each other have a second water content higher than WC SiHy , as characterized either (a) by having a water-swelling ratio WSR of at least about 150% if WC SiHy ≦45% or (b) by having a water-swelling ratio of at least about
130
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%,
wherein the thickness of each of the anterior and posterior outer hydrogel layers is from about 0.1 μm to about 20 μm, as measured with atomic force microscopy across a cross section from the posterior surface to the anterior surface of the silicone hydrogel contact lens in fully hydrated state.
2. The silicone hydrogel contact lens of claim 1 , wherein the thickness of each of the anterior and posterior outer hydrogel layers is from about 0.25 μm to about 15 μm, as measured with atomic force microscopy across a cross section from the posterior surface to the anterior surface of the silicone hydrogel contact lens in fully hydrated state.
3. The silicone hydrogel contact lens of claim 1 , wherein the thickness of each of the anterior and posterior outer hydrogel layers is from about 0.5 μm to about 12.5 μm, as measured with atomic force microscopy across a cross section from the posterior surface to the anterior surface of the silicone hydrogel contact lens in fully hydrated state.
4. The silicone hydrogel contact lens of claim 1 , wherein the thickness of each of the anterior and posterior outer hydrogel layers is from about 1 μm to about 10 μm, as measured with atomic force microscopy across a cross section from the posterior surface to the anterior surface of the silicone hydrogel contact lens in fully hydrated state.
5. The silicone hydrogel contact lens of claim 1 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 200% if WC SiHy ≦45% or a water-swelling ratio of at least about
140
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
6. The silicone hydrogel contact lens of claim 2 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 200% if WC SiHy ≦45% or a water-swelling ratio of at least about
140
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
7. The silicone hydrogel contact lens of claim 3 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 200% if WC SiHy ≦45% or a water-swelling ratio of at least about
140
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
8. The silicone hydrogel contact lens of claim 4 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 200% if WC SiHy ≦45% or a water-swelling ratio of at least about
140
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
9. The silicone hydrogel contact lens of claim 1 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 250% if WC SiHy ≦45% or a water-swelling ratio of at least about
150
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
10. The silicone hydrogel contact lens of claim 2 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 250% if WC SiHy ≦45% or a water-swelling ratio of at least about
150
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
11. The silicone hydrogel contact lens of claim 3 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 250% if WC SiHy ≦45% or a water-swelling ratio of at least about
150
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
12. The silicone hydrogel contact lens of claim 4 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 250% if WC SiHy ≦45% or a water-swelling ratio of at least about
150
·
WC
SiHy
1
-
WC
SiHy
%
if WC SiHy >45%.
13. The silicone hydrogel contact lens of claim 1 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 300%.
14. The silicone hydrogel contact lens of claim 2 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 300%.
15. The silicone hydrogel contact lens of claim 3 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 300%.
16. The silicone hydrogel contact lens of claim 4 , wherein the anterior and posterior outer hydrogel layers independent of each other have a water-swelling ratio WSR of at least about 300%.
17. The silicone hydrogel contact lens of claim 1 , wherein the anterior and posterior outer hydrogel layers are substantially free of silicone.
18. The silicone hydrogel contact lens of claim 2 , wherein the anterior and posterior outer hydrogel layers are substantially free of silicone.
19. The silicone hydrogel contact lens of claim 3 , wherein the anterior and posterior outer hydrogel layers are substantially free of silicone.
20. The silicone hydrogel contact lens of claim 4 , wherein the anterior and posterior outer hydrogel layers are substantially free of silicone.