U.S. patent application number 15/920639 was filed with the patent office on 2018-07-19 for methods and apparatus to enhance oxygen concentrations for ophthalmic devices.
The applicant listed for this patent is Johnson & Johnson Vision Care, Inc.. Invention is credited to Frederick A. Flitsch, Randall B. Pugh, Adam Toner.
Application Number | 20180203253 15/920639 |
Document ID | / |
Family ID | 58549020 |
Filed Date | 2018-07-19 |
United States Patent
Application |
20180203253 |
Kind Code |
A1 |
Pugh; Randall B. ; et
al. |
July 19, 2018 |
METHODS AND APPARATUS TO ENHANCE OXYGEN CONCENTRATIONS FOR
OPHTHALMIC DEVICES
Abstract
Methods and apparatus to enhance levels of oxygen in tear fluid
under a worn advanced contact lens are described. The contact lens
may include an encapsulated hard lens element which is impermeable
to fluid flow across its body. The method of enhancement may
include creating pores through the hard lens element, creating
channels in portions of the contact lens body, including layers of
absorptive material, and creating means of moving tear fluid under
the contact lens.
Inventors: |
Pugh; Randall B.; (St.
Johns, FL) ; Toner; Adam; (Jacksonville, FL) ;
Flitsch; Frederick A.; (New Windsor, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Johnson & Johnson Vision Care, Inc. |
Jacksonville |
FL |
US |
|
|
Family ID: |
58549020 |
Appl. No.: |
15/920639 |
Filed: |
March 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15098816 |
Apr 14, 2016 |
9977258 |
|
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15920639 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02C 7/047 20130101;
G02C 2202/06 20130101; G02C 7/049 20130101; G02C 11/10
20130101 |
International
Class: |
G02C 7/04 20060101
G02C007/04; G02C 11/00 20060101 G02C011/00 |
Claims
1. A contact lens comprising: a hydrogel skirt, wherein the
hydrogel skirt is molded into a shape of the contact lens, with an
arcuate back surface placed proximate to a user's cornea during a
use of the contact lens; an encapsulated hard lens element, wherein
the encapsulated hard lens element is gas impermeable and
impermeable to fluid flow through its body, wherein the
encapsulated hard lens element is encapsulated within the hydrogel
skirt, the encapsulated hard lens element comprising a dual chamber
structure with one chamber positioned above the other chamber; a
first region of the hydrogel skirt, wherein the first region of the
hydrogel skirt is that portion of the hydrogel skirt that is
between a surface of the encapsulated hard lens element and a
cornea of a user during the use of the contact lens; and an
absorptive material, wherein the absorptive material absorbs oxygen
gas.
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. The contact lens according to claim 1, wherein the absorptive
material comprises hemoglobin.
9. The contact lens according to claim 1, wherein the absorptive
material comprises hemocyanin.
10. The contact lens according to claim 1, wherein the absorptive
material comprises a porphyrin based material.
11. The contact lens according to claim 1, wherein the absorptive
material comprises a metal organic framework molecular species.
12. (canceled)
13. A method of enhancing oxygen levels at a user's cornea when the
user wears a contact lens, the method comprising: forming a layer
of oxygen absorptive material within a body of the contact lens;
placing the contact lens in an ambient with high partial pressure
of oxygen; and providing the contact lens, wherein during a use of
the contact lens, oxygen diffuses from the absorptive material to a
region of tear fluid underneath the contact lens.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] Methods and apparatus to enhance the concentration of oxygen
at the interface of an ophthalmic device with the user's eyes are
described. In some embodiments, the methods and apparatus to
enhance oxygen concentration involve forming pores which are
non-perturbative to imagining through the ophthalmic device. In
some embodiments, storage of oxygen is involved. In some
embodiments, movement of fluids which contain oxygen provides a
solution. In some embodiments, a field of use for the methods and
apparatus may include any ophthalmic device or product utilizing an
embedded hard lens device.
2. Discussion of the Related Art
[0002] Recently, the number of medical devices and their
functionality has begun to rapidly develop. A significant advance
has been made in the field of ophthalmics, where electroactive
functions are being incorporated into ophthalmic lenses. Some
embodiments of these devices may include components such as
semiconductor devices that perform a variety of functions. However,
such semiconductor components require energy and, thus,
energization elements may typically also be included in such
biocompatible devices. The shape and relatively small size of the
biocompatible devices creates novel and challenging environments
for the definition of various functionalities. In many embodiments,
it may be important to provide safe, reliable, compact and cost
effective means comprising an insert device to contain the
electroactive components and energization elements within the
biocompatible devices. In some examples, a passive, hard and
non-permeable lens device may also prevent diffusion of various
materials across their body. The net effect may be to decrease an
inherent ability of oxygen to be located on the eye surface under
the ophthalmic device. Therefore, a need exists for novel
embodiments of ophthalmic devices to enhance transport of oxygen
into the region proximate to the eye surface
SUMMARY OF THE INVENTION
[0003] Accordingly, methods and apparatus to enhance levels of
oxygen (which may also be called oxygen gas or oxygen molecules)
present in the region between a back surface of a worn ophthalmic
device and the user's eye are disclosed.
[0004] The cornea receives oxygen from the air and the aqueous
humor. Aqueous humor is blood filtrate which is essentially blood
minus the red blood cells. It is transparent and provides nutrients
to both the cornea and the crystalline lens. The ciliary body
provides the aqueous humor through the ciliary process. The
pre-corneal tear film comprises three layers. The outermost layer
is the superficial oily layer, the inner most layer is the mucoid
layer and the middle layer which is ninety-eight percent of the
tear film is the tear fluid or aqueous layer. The middle layer is
responsible for oxygen uptake to maintain corneal cyanate,
polyfluorinated hydrocarbon, polyfluorinated ether and
polysaccharide groups; poly the cornea via osmosis.
[0005] A healthy cornea requires both oxygen and nutrients from the
mechanisms described above. Today's silicone hydrogel contact
lenses provide for sufficient oxygen transmission from the air to
the teats to the cornea. However, advanced contact lenses such as
electronic lenses comprise sealed inserts which may potentially
limit oxygen transport. There are also examples of
non-electroactive lens systems that incorporate hard lens elements
that are encapsulated into a hydrogel exterior, and these lens
systems may also have issues with oxygen levels at the user's eye
surface due to impermeability of the hard lens elements.
Accordingly, the present invention is directed to various means for
ensuring sufficient oxygen transmission to the cornea. In one
embodiment, diffusion pores within the body of the encapsulated
hard lens element allow for oxygen diffusion through the
encapsulated hard lens element body. In another embodiment, the
lens may be designed to store an increased level of oxygen in the
body of the lens using various materials or through storage or
containment vessels. In yet still another embodiment, passive and
active pumping mechanisms may be utilized to move oxygen rich
fluids around different regions of the eye.
[0006] In some examples a contact lens is provided comprising a
hydrogel skirt molded into the shape of a contact lens with an
arcuate back surface placed proximate to a user's cornea during a
use of the contact lens. The contact lens also includes an
encapsulated hard lens element, wherein the encapsulated hard lens
element is gas impermeable and impermeable to fluid flow through
its body. The hard lens element is encapsulated within the hydrogel
skirt. And, the encapsulated hard lens element comprises one or
more components mounted thereupon. The contact lens has a first
region of the hydrogel skirt, wherein the first region of the
hydrogel skirt is that portion of the hydrogel skirt that is
between a surface of the encapsulated hard lens element and a
cornea of a user during the use of the contact lens. The exemplary
contact lens also includes a means within the contact lens of
enhancing oxygen levels within a fluid in contact with the first
region.
[0007] In some examples, the means within the contact lens of
enhancing oxygen levels within the fluid in contact with the first
region comprises at least a first pore in the hard lens element,
wherein the pore traverses the body of the hard lens element. In
some examples, the pore is back-filled with a silicone containing
material. In some examples, the first pore is one of a plurality of
pores, wherein the plurality of pores traverse the body of the hard
lens element. In some examples, the plurality of pores are
back-filled with the silicone containing material.
[0008] In some examples, the means within the contact lens of
enhancing oxygen levels within the fluid in contact with the first
region comprises a layer of absorptive material, wherein the
absorptive material absorbs oxygen gas. In some examples, the
absorptive material comprises hemoglobin. In some examples, the
absorptive material comprises hemocyanin. In some examples, the
absorptive material comprises a porphyrin based material. In some
examples, the absorptive material comprises a metal organic
framework molecular species.
[0009] One general aspect includes methods which enhance oxygen
levels at a user's cornea when the user wears a contact lens. The
methods may include forming a pore through a hard lens element.
Next the method may include backfilling the pore with a silicone
containing polymer; and providing the contact lens comprising the
encapsulated hard lens element, wherein during the use of the
contact lens, oxygen diffuses through the pore with the silicone
containing polymer to a region of tear fluid underneath the contact
lens.
[0010] Another general aspect includes methods which enhance oxygen
levels at a user's cornea when the user wears a contact lens. The
method includes forming a layer of oxygen absorptive material
within a body of the contact lens. The method also includes placing
the contact lens in an ambient with high partial pressure of
oxygen. Next the method continues by providing the contact lens,
wherein during a use of the contact lens, oxygen diffuses from the
absorptive material to a region of tear fluid underneath the
contact lens.
[0011] Another general aspect includes methods which enhance oxygen
levels at a user's cornea when the user wears a contact lens. The
method includes forming a plurality of channels in an arcuate back
curved region of a hydrogel skirt of the contact lens. The method
also includes forming a raised region of hydrogel skirt above a
first enlarged channel in the arcuate back curved region of the
hydrogel skirt of the contact lens; and providing the contact lens,
wherein during the use of the contact lens an eyelid of the user
forces the raised region of hydrogel skirt to compress the first
enlarged channel in the arcuate back curved region of the hydrogel
skirt, wherein the compression causes tear fluid to move underneath
the contact lens, wherein the contact lens comprises an hard lens
element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing and other features and advantages of the
invention will be apparent from the following, more particular
description of preferred embodiments of the invention, as
illustrated in the accompanying drawings.
[0013] FIGS. 1A-1B illustrate exemplary aspects of contact lenses
with inserts, electroactive components and energization
elements.
[0014] FIGS. 1C-1D illustrate exemplary aspects of a contact lens
upon a user's eye with cross sectional focus on the region under
the insert above the user's eye.
[0015] FIG. 2A illustrates a cross section of exemplary aspects of
a two chamber electroactive optic system within an insert and a
hydrogel skirt.
[0016] FIG. 2B illustrates a cross section illustrating the cutting
of an exemplary through via in an exemplary insert device.
[0017] FIG. 2C illustrates a cross section illustrating exemplary
filling with hydrogel of the through via in an exemplary insert
device.
[0018] FIG. 2D illustrates exemplary placement of through vias
within the body of an exemplary advanced contact lens.
[0019] FIG. 2E illustrates an exemplary cross section with
multilayer insert and hydrogel skirt with fluted through vias.
[0020] FIG. 3A illustrates exemplary incorporation of oxygen
absorptive material within the body of an exemplary advanced
contact lens.
[0021] FIG. 3B illustrates exemplary electronically triggered
oxygen containment elements within the body of an exemplary
advanced contact lens.
[0022] FIG. 4A illustrates a cross section of an exemplary
electroactive pumping mechanism within the body of an exemplary
advanced contact lens.
[0023] FIG. 4B illustrates an exemplary top down view of an
electroactive pumping mechanism within the body of an exemplary
advanced contact lens.
[0024] FIG. 5 illustrates an exemplary passive channel system that
may interact with eyelid blinking to move fluids under an exemplary
advanced contact lens.
[0025] FIG. 6 illustrates an exemplary contact lens including a
hard impermeable device encapsulated into its body.
[0026] FIG. 7A illustrates an exemplary laser process to cut pores
through a hard impermeable device which may be encapsulated into a
lens body.
[0027] FIG. 7B illustrates encapsulating a hard impermeable device
including a pore with hydrogel encapsulant.
[0028] FIG. 8 illustrates exemplary incorporation of oxygen
absorptive material within the body of an exemplary contact
lens.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Methods and apparatus to increase oxygen levels present in
the region between an ophthalmic contact lens and a user's eye
surface are disclosed in this application. In some examples, the
hydrogel skirt used to surround an electroactive insert and provide
various functions relating to an electroactive contact lens may
itself be a good medium to foster the transport of oxygen around
the region that intersects with a contact lens. Therefore, in
regions of a contact lens with an imbedded insert that are on the
peripheries of the insert body, there may be very good transport of
oxygen from the air or ambient environment to the user's eye
surface. In some examples, the nature of the formulation, thickness
and design of the hydrogel skirt may be aid in realizing a contact
lens where sufficient levels of oxygen are present across the
user's eye surface. In other examples, other features of the
contact lens may be important to realize good oxygen levels in the
region between the back surface of the contact lens and the top
surface of the user's eye, where the intervening region may also
include tear fluid from the user.
Glossary
[0030] In the description and claims below, various terms may be
used for which the following definitions will apply:
[0031] "Biocompatible" as used herein refers to a material or
device that performs with an appropriate host response in a
specific application. For example, a biocompatible device does not
have toxic or injurious effects on biological systems.
[0032] "Coating" as used herein refers to a deposit of material in
thin forms. In some uses, the term will refer to a thin deposit
that substantially covers the surface of a substrate it is formed
upon. In other more specialized uses, the term may be used to
describe small thin deposits in smaller regions of the surface.
[0033] "Energized" as used herein refers to the state of being able
to supply electrical current or to have electrical energy stored
within.
[0034] "Energy" as used herein refers to the capacity of a physical
system to do work. Many uses of the energization elements may
relate to the capacity of being able to perform electrical
actions.
[0035] "Energy Source" or "Energization Element" or "Energization
Device" as used herein refers to any device or layer which is
capable of supplying energy or placing a logical or electrical
device in an energized state. The energization elements may include
battery cells. The batteries can be formed from alkaline type cell
chemistry and may be solid-state batteries or wet cell
batteries.
[0036] "Film" as used herein refers to a thin layer of a material
that may act as a covering or a coating; in laminate structures the
film typically approximates a planar layer with a top surface and a
bottom surface and a body; wherein the body is typically much
thinner than the extent of the layer.
[0037] "Mold" as used herein refers to a rigid or semi-rigid object
that may be used to form three-dimensional objects from uncured
formulations. Some preferred molds include two mold parts that,
when opposed to one another, define the structure of a
three-dimensional object.
Exemplary Biomedical Device Construction with Encapsulated
Inserts
[0038] An example of a biomedical device that may incorporate an
insert containing energization elements and electroactive elements
may be an electroactive focal-adjusting contact lens. Referring to
FIG. 1A, an example of such a contact lens insert may be depicted
as contact lens insert 100. In the contact lens insert 100, there
may be an electroactive element 120 that may accommodate focal
characteristic changes in response to controlling voltages. A
circuit 105 to provide those controlling voltage signals as well as
to provide other function such as controlling sensing of the
environment for external control signals may be powered by an
energization element such as a biocompatible battery element 110.
As depicted in FIG. 1A, the energization element may be found as
multiple major pieces, in this case three pieces, and may comprise
various configurations of elements. The energization elements may
have various interconnect features to join together pieces as may
be depicted underlying the region of interconnect 114. The
energization elements may be connected to a circuit element that
may have its substrate 111 upon which interconnect features 125 may
be located. The circuit 105, which may be in the form of an
integrated circuit, may be electrically and physically connected to
the substrate 111 and its interconnect features 125.
[0039] Referring to FIG. 1B, a cross sectional relief of a contact
lens 150 may contain contact lens insert 100 and its discussed
constituents. The contact lens insert 100 may be encapsulated into
a skirt of contact lens hydrogel 155 which may encapsulate the
insert and provide a comfortable interface of the contact lens 150
to a user's eye.
[0040] Referring to FIG. 1C, the cross sectional relief of FIG. 1B
is illustrated superimposed upon a user's eye 170. There may be
regions on the surface of the user's eye that may lie under a
region of the lens that contains an insert such as region 190. And,
there may be regions on the surface of the user's eye that may lie
under only the hydrogel skirt such as region 180. In some examples
the level of oxygenation in a region of tear fluid and surface
tissue may be less in region 190 than in region 180 due to the
inhibition of oxygen diffusion from an ambient gas which may be
located exterior to the contact lens to the surface of the user's
eye. In these examples, other design aspects of the contact lens
with encapsulated insert may be warranted.
[0041] Referring to FIG. 1D, a cross sectional blow up of a portion
of the region 180 under an insert is illustrated. A surface of the
user's eye 181, or cornea is illustrated. Above the surface of the
user's eye 181 may naturally occur a thin layer of tear fluid 182
that the lens is supported upon. On the other side of the thin
layer of tear fluid 182 may be a portion of the hydrogel skirt 183.
The shape of the hydrogel skirt which is proximate to a user's
cornea or eye may be called an arcuate surface, and this surface
may also be called the back surface or back curve surface therefore
it may be an arcuate back surface or an arcuate back curved
surface. The cross section of FIG. 1D is illustrated at the edge of
the lens insert 184. Therefore, a variable thickness layer of the
lens skirt 185 above the lens insert 184 is illustrated. The region
of the hydrogel skirt under the insert and the associated portion
of the layer of tear fluid under the insert may be a region of
decreased oxygen levels due to the fact that the lens insert 184
prevents diffusion through its body and the user's eye 181 is
consuming oxygen. The tear fluid 182 may also have decreased oxygen
level.
Diffusion "Pores" within the Body of an Encapsulated Insert.
[0042] Referring to FIG. 2A a cross section of an encapsulated
insert is illustrated. In the example, a dual chamber insert may be
found. An outer layer may form a top surface 211 of the insert.
And, another outer layer may form the bottom surface 214 of the
insert. In some examples, these insert surfaces may have shapes and
forms to relate to desired optical effects of the insert structure
such as being shaped to add power to the lens effect of the insert.
In examples with multiple chambers, such as illustrated in FIG. 2A,
an intermediate piece 217 may also be formed. In a likewise fashion
to the outer layers, the intermediate piece 217 may be shaped to
related to optical effects of the lens structure. In some examples,
the chambers may have internal structures which may define the
structural height of a chamber in a region. These structures may be
called spacer's. The first chamber 212 may have a first chamber
spacer 213 and the second chamber 215 may have a second chamber
spacer 216. In some examples, the location of the spacers may be
unrelated to each other, in the example illustrated they may align
which may allow for a pore to be formed in the center of them which
penetrates through the entire body and out of each insert surface.
The spacers may be located in the chambers in regions that are
located in the optic zone of the ophthalmic lens, where the optic
zone is the portion of the lens where light passes through from an
object on its way to the user's retina. If the spacer is located in
the optic zone, it may interact with the light rays passing through
forming an image. Therefore, it may be important that the spacer is
kept to a minimal size. In some examples, the size may be less than
100 microns. In further examples, the size may be less than 50
microns. In still further examples the size may be less than 20
microns.
[0043] A spacer column may be formed by the overlay of the first
chamber spacer 213 and the second chamber spacer 216. Referring to
FIG. 2B, the cutting of a pore 221 is illustrated. In some
examples, the pore may be cut by a laser light source 220. As an
example, a Ytterbium fiber based laser may be focused to drill
holes in materials such as plastics with dimensions as small as
10-20 microns in size. Any laser drilling type equipment may be
used to create the pore through the top surface 211, the first
chamber spacer 213, the second chamber spacer 216 and the bottom
surface 214. In some examples other methods of creating a pore may
be utilized such as in a non-limiting example a photolithography
process to image a photoresist mask followed by a reactive ion
etching process through the layers. Any technique to drill a small
profile hole through insert pieces may be utilized.
[0044] The pore 221 may be a path that allows oxygen to diffuse
through the insert from the front of the electroactive lens to the
back of the electroactive lens. If the pore exists in an
encapsulated lens, the diffusion of tear fluid through the pore
along with dissolved oxygen in the tear fluid may enhance oxygen
levels along tissues of the user's eye surface under the lens
insert region (as was depicted as 180 in FIG. 1C). In some
examples, oxygen permeation may be very effective in hydrogel
layers. Referring to FIG. 2C, a hydrogel layer 230 used to
encapsulate a lens insert may also fill (or "back-fill") the pore
with a layer of hydrogel in the pore 231. Oxygen may diffuse
through tear fluid and hydrogel from a front surface through the
lens body and into the hydrogel layers on the back surface of the
lens and ultimately into a layer of tear fluid between the lens and
the eye surface where it can then diffuse to the tissue layers of
the eye.
[0045] Referring to FIG. 2D, a top down view of a lens insert with
pores drilled through the body in various locations is illustrated.
As illustrated, in an example, there may be five (5) holes cut into
the insert device at features 271, 272, 273, 274 and 275. The
actual number of pores may be more or less than those illustrated
depending on a number of factors including factors such as
degradation in imaging through the lens by the presence of pores
and the effectiveness of increased oxygen levels versus distance
from a pore. There may be other factors that impact the design of
the pores individually and their pattern and number in the insert
body.
[0046] It may be desirable to form the pore with a diameter on the
order of approximately 20 microns. In order to fill the pore with
hydrogel monomer, it may be desirable to evacuate the pore of
gasses before filling a mold with monomer around the insert. By
evacuating the gas phase around and within the pore, a better
filling with monomer may result.
[0047] Referring to FIG. 2E an exemplary contact lens is
illustrated in cross section. The contact lens skirt 280 in cross
section, and 281 view from behind may surround an insert. The
insert may have two chambers, a first chamber 283 and a second
chamber 284. Through vias or holes are illustrated such as the
exemplary through via 282. As illustrated, the laser drilling
processing may result in profiles to the holes that are fluted with
wider diameter near the surface of the lens.
Oxygen Absorption and Desorption
[0048] Another manner to increase oxygen in the space between an
advanced contact lens and the eye surface may be to store an
increased level of oxygen in the body of the lens. The increased
level may be imparted to the lens by storing the lens in a
pressurized oxygen environment before packaging the lens. There may
be a number of material additions to layers in the lens that may
impart the ability to store oxygen from the pressurized atmosphere.
Ideally the materials that store the oxygen will desorb the oxygen
as the level of oxygen in its vicinity drops. In other examples,
the stored oxygen may be desorbed under an influence such as by the
heating of the material.
[0049] Referring to FIG. 3A, a layer of absorptive material 310 may
be embedded within an advanced contact lens. The general structure
of the insert example is illustrated as in previous depictions
including a top surface 211, a first chamber 212, a first chamber
spacer 213, a bottom surface 214, a second chamber 215 and a second
chamber spacer 216. In some examples, there may be a through via or
pore 221. In some examples, the absorptive material 310 may be
deposited on the surface of the insert. In other examples, it may
be embedded within the hydrogel skirt layer as a film or as in
entrapped discrete elements. In some examples, the absorptive
material 310 may be synthetic organometallic moieties based upon
natural oxygen transport molecules or may be biological oxygen
transport molecules such as hemoglobin, hemocyanin, another
porphyrin based species or another metal organic framework
molecular species. The absorptive material 310 may comprise
metallic species such as iron, copper, and zirconium as
non-limiting examples. These organometallic species may be
integrated into the hydrogel layer and may reversibly desorb oxygen
into the hydrogel layer. In some examples, desorption may be
stimulated by electrical action on the layers of absorptive
material, such as heating them. Due to the nature of the use
environment, such heating may be limited to small regions of the
absorptive material at a time. Other similar organic molecules may
be embedded to perform a similar function.
[0050] In other examples, the absorptive material may comprise
absorptive particles, such as zeolites that may be charged with
oxygen. The particles may maintain an equilibrium level of oxygen
in their surroundings. Therefore, when a package containing the
advanced contact lens device is opened for use, a release of oxygen
may occur, and the absorptive particle may begin desorbing oxygen.
In some examples, the absorptive material may include zeolites of
various composition such as sodium, cerium, silicon and aluminum
for example. In other examples the absorptive/adsorptive material
may comprise polymers and doped polymers which absorb oxygen, such
as polymers with unsaturated regions or phenolic regions in the
backbone. Polymers may be doped with other species such as copper
for example in a polyester and poly-butadiene structure. A super
saturation of these absorptive particles under high pressure, high
concentration and/or high partial pressure of oxygen, may result in
a material that releases oxygen in low levels over time when the
oxygen level in the ambient drops.
[0051] Referring to FIG. 3B, an alternative but related device
structure is illustrated. The general structure of the insert
example is illustrated as in previous depictions including a top
surface 211, a first chamber 212, a first chamber spacer 213, a
bottom surface 214, a second chamber 215 and a second chamber
spacer 216. In some examples, there may be a through via or pore
221. A surface of the insert may be formed to comprise a series of
oxygen containment or oxygen generation vessels shown as vessels
350. In some example the vessels 350 may contain pressurized
oxygen. An electrically controllable release feature 360 may be
formed upon the vessel containing the pressurized oxygen and upon
an electric signal may release the oxygen. In some examples, the
electrical signal may cause a thin metallic foil to melt in the
process of releasing the stored oxygen.
[0052] In other examples, the vessel 350 may contain a segregated
region of an oxygen containing chemical such as hydrogen peroxide.
The electrically controllable release feature 360 may in these
cases release hydrogen peroxide to flow into another region of the
device where it may interact with a catalytic surface, such as the
surface of zeolites, where the peroxide may decompose into water
and evolved oxygen. In some examples, the vessel may be capped with
a membrane that may allow oxygen to diffuse through while
containing the other components such as the catalytic surface
within the vessel.
[0053] The electroactive oxygen generator or releasing structure
may be electrically programmed to be released at a particular time
after a use cycle begins. A large number of these features may
therefore be slowly and regionally triggered to enhance oxygen
levels during a use cycle across regions underneath an insert of an
advanced contact lens.
Movement of Oxygen Rich Fluids to Enhance Oxygenation
[0054] The general environment around an advanced contact lens
during its use has ample levels of oxygen. However, in some cases
the inhibition of diffusion through a contact lens by a sealed
insert may be coupled with the fact that the thin layer of tear
fluid between the hydrogel surface of the contact lens and the eye
surface may not move significantly to exchange with more oxygenated
regions peripheral to the insert region. In practice the hydrogel
layers may provide effective transport of oxygen from peripheral
regions towards regions under the insert, but the tissue in those
regions may be consuming oxygen at a significant rate. Thus, if
enhanced oxygen transport may be needed, it may be useful to
enhance the movement of tear fluid under the insert region into and
out of that region.
[0055] Referring to FIGS. 4A and 4B an electroactive pump 410 may
be used to move fluid, more specifically tear fluid proximate to a
user's eye surface. The general structure of the insert example is
illustrated in FIG. 4A as in previous depictions including a top
surface 211, a first chamber 212, a first chamber spacer 213, a
bottom surface 214, a second chamber 215 and a second chamber
spacer 216. In some examples, there may be a through via or pore
221. As a relevant aside, if the tear fluid and hydrogel materials
are matched relative to their index of refraction it may be
possible to create channels 420 in the hydrogel that may fill with
tear fluid, but which may not create an optically interacting
structure. In some examples, when illustrated from top down,
channels may be formed to include flow directing aspects, such as
flap valves or profiled surfaces which may favor one direction of
flow rather than another. In some examples, the height of such a
channel may be less than approximately 20 microns and the width may
be approximately 20-50 microns. In further examples, the height of
such a channel may be less than approximately 5 microns. In still
further examples, the height of such a channel may be less than
approximately 1 micron. There may be numerous examples of heights
and widths outside these exemplary amounts.
[0056] When illustrated from top down, an inward flowing channel
430 and an outward flowing channel 440 is illustrated. Again, very
small features may be molded into the hydrogel to form these
channels and the analog of flow check valves into the shape of the
channels. The electroactive pump 410 may be comprised of a portion
that expands or contracts upon an electrical signal, such as a
piezoceramic or piezoelectric based transducer or electroactive
elastomer or electroactive polymer based transducer. By contracting
an electroactive body 411, an attached hydrogel feature 412 may
move opening up the volume in a chamber 413 under the device. When
the volume is opened up, fluid may be drawn into the chamber 413.
In the opposite case, when the electrical signal is removed or
reversed, the electroactive body 411 may expand, move down the
hydrogel feature 412 and cause fluid in the chamber 413 to be
pushed out of channels. Thus, oxygen laden fluid may be moved from
peripheral regions through a network of channels under the insert
region of an advanced contact lens. In some examples, a relatively
slow and steady pumping action may result in the user not being
perturbed either physically or optically during the pumping action.
In some other examples, the pumping action may be programmed to be
intermittent and may, for example, coincide with a detection of
blinking of the eye.
[0057] Referring to FIG. 5 a similar channel based distribution of
oxygenated fluid is illustrated where the pumping mechanism may be
passive, i.e. may not involve an electroactive pump. When a user's
eye lid blinks it may impart force to engage a pumping mechanism.
In some examples, the force may compress channels and allow for
fluid to be squeezed out of the channels in the region under the
insert 511 to the peripheral region 510. After the lid moves by,
the channels may again expand drawing new oxygen laden fluid in
from the peripheral regions. In another example, there may be
protrusions 520 in the peripheral regions of the lens that are
forced downward as the user's eyelid goes by them in both
directions. With an appropriate level of flow direction (i.e. check
valve type action) in the channels, the force downward on the
protrusions and their effect on neighboring regions may pump fluid
along a network of channels 530 exchanging fluid from external
regions to internal regions. In some examples, the channels 530 may
be formed into a hydrogel encapsulating skirt and may be
approximately 50 microns or less in height and a width that
maintains the presence of a channel when the contact lens is worn.
As an example, the width of a channel 530 may also be approximately
50 microns in dimension or less. The protrusions may be made smooth
and shallow in some examples to enhance comfort in a user while
affording the necessary forced interaction for engagement of a
pumping action.
Diffusion "Pores" within the Body of an Encapsulated Hard Lens
Device.
[0058] In some examples, a lens may be formed that has a hard
encapsulated element within its body that may at least partially
inhibit diffusion of oxygen through the lens body. However in some
examples, the hard encapsulated element may be a relatively simple
passive element without structures such as energization elements,
circuits, and electroactive components. In fact, in some examples,
the hard encapsulated element may be just a lens body. In a
non-limiting example, such a composite lens may be used to add
physical tension to reshape a user's cornea. Referring to FIG. 6,
an illustration of a lens with an encapsulated hard lens device is
provided. A hard impermeable element 610 may be encapsulated in a
soft lens skirt 620. Nevertheless, the fluids at the surface of the
user's eye under the hard lens portion may experience a deficit of
oxygen during use where some of the strategies discussed herein may
be helpful.
[0059] Referring to FIG. 7A, the hard lens element 700 is
illustrated with a pore 720 being cut by an exemplary laser
irradiation 710. The pore 720 may be a structural element that may
be formed small enough in dimension not to interfere with vision.
Nevertheless, the pore 720 may allow oxygen to diffuse through the
hard lens element 700 body. Continuing with FIG. 7B, the
impermeable, hard lens element 700 with a pore 720 may be
encapsulated with hydrogel. The hydrogel may form the lens skirt
740 and fill in the pore 741. As mentioned in concert with an
advanced lens, such a pore particularly when backfilled with
hydrogel may provide an improvement of oxygen diffusion amounts to
the region under the lens structure.
Oxygen Absorption and Desorption within the Body of a Contact Lens
with an Encapsulated Hard Lens Element
[0060] Another manner to increase oxygen in the space between a
contact lens with an encapsulated hard lens element and the eye
surface may be to store an increased level of oxygen in the body of
the lens. The increased level may be imparted to the lens by
storing the lens in a pressurized oxygen environment before
packaging the lens. There may be a number of material additions to
layers in the lens that may impart the ability to store oxygen from
the pressurized atmosphere. Ideally the materials that store the
oxygen will desorb the oxygen as the level of oxygen in its
vicinity drops.
[0061] Referring to FIG. 8, a layer of absorptive material 830 may
be embedded within a contact lens with a hard lens element 810 and
a hydrogel skirt 820. In some examples, the absorptive material 830
may be deposited on the surface of the hard lens element 810. In
other examples, it may be embedded within the hydrogel skirt layer
as a film or as in entrapped discrete elements. In some examples,
the absorptive material 830 may be synthetic organometallic
moieties based upon natural oxygen transport molecules or may be
biological oxygen transport molecules such as hemoglobin,
hemocyanin, another porphyrin based species or another metal
organic framework molecular species. The absorptive material 830
may comprise metallic species such as iron, copper, and zirconium
as non-limiting examples. These organometallic species may be
integrated into the hydrogel layer and may reversibly desorb oxygen
into the hydrogel layer. Other similar organic molecules may be
embedded to perform a similar function.
[0062] In other examples, the absorptive material 830 may comprise
absorptive particles, such as zeolites that may be charged with
oxygen. The particles may maintain an equilibrium level of oxygen
in their surroundings. Therefore, when a package containing the
advanced contact lens device is opened for use, a release of oxygen
may occur, and the absorptive particle may begin desorbing oxygen.
In some examples, the absorptive material may include zeolites of
various composition such as sodium, cerium, silicon and aluminum
for example. In other examples the absorptive/adsorptive material
may comprise polymers and doped polymers which absorb oxygen, such
as polymers with unsaturated regions or phenolic regions in the
backbone. Polymers may be doped with other species such as copper
for example in a polyester and poly-butadiene structure. A super
saturation of these absorptive particles under high pressure, high
concentration and/or high partial pressure of oxygen, may result in
a material that releases oxygen in low levels over time when the
oxygen level in the ambient drops.
Materials for Lens Formation and Lens Skirts
[0063] Microinjection molding examples may include, for example, a
poly (4-methylpent-1-ene) copolymer resin are used to form lenses
with a diameter of between about 6 mm to 10 mm and a front surface
radius of between about 6 mm and 10 mm and a rear surface radius of
between about 6 mm and 10 mm and a center thickness of between
about 0.050 mm and 1.0 mm. Some examples include an hard lens
element with diameter of about 8.9 mm and a front surface radius of
about 7.9 mm and a rear surface radius of about 7.8 mm and a center
thickness of about 0.200 mm and an edge thickness of about 0.050
mm.
[0064] The hard lens element 600 illustrated in FIG. 6 may be
placed in a mold part utilized to form an ophthalmic lens. The
material of mold parts may include, for example, a polyolefin of
one or more of: polypropylene, polystyrene, polyethylene,
polymethyl methacrylate, and modified polyolefins. Other molds may
include a ceramic or metallic material.
[0065] A preferred alicyclic co-polymer contains two different
alicyclic polymers. Various grades of alicyclic co-polymers may
have glass transition temperatures ranging from 105.degree. C. to
160.degree. C.
[0066] In some examples, the molds of the present invention may
contain polymers such as polypropylene, polyethylene, polystyrene,
polymethyl methacrylate, modified polyolefins containing an
alicyclic moiety in the main chain and cyclic polyolefins. This
blend may be used on either or both mold halves, where it is
preferred that this blend is used on the back curve and the front
curve consists of the alicyclic co-polymers.
[0067] In some preferred methods of making molds according to the
present invention, injection molding is utilized according to known
techniques, however, examples may also include molds fashioned by
other techniques including, for example: lathing, diamond turning,
or laser cutting.
[0068] In some examples, a preferred lens material includes a
silicone containing component. A "silicone-containing component" is
one that contains at least one [--Si--O--] unit in a monomer,
macromer or prepolymer. Preferably, the total Si and attached O are
present in the silicone-containing component in an amount greater
than about 20 weight percent, and more preferably greater than 30
weight percent of the total molecular weight of the
silicone-containing component. Useful silicone-containing
components preferably comprise polymerizable functional groups such
as acrylate, methacrylate, acrylamide, methacrylamide, vinyl,
N-vinyl lactam, N-vinylamide, and styryl functional groups.
[0069] In some examples, the ophthalmic lens skirt, also called an
insert-encapsulating layer, that surrounds the insert or hard lens
element may be comprised of standard hydrogel ophthalmic lens
formulations. Exemplary materials with characteristics that may
provide an acceptable match to numerous insert materials may
include, the Narafilcon family (including Narafilcon A and
Narafilcon B), and the Etafilcon family (including Etafilcon A). A
more technically inclusive discussion follows on the nature of
materials consistent with the art herein. One ordinarily skilled in
the art may recognize that other material other than those
discussed may also form an acceptable enclosure or partial
enclosure of the sealed and encapsulated inserts and should be
considered consistent and included within the scope of the
claims.
[0070] Suitable silicone containing components include compounds of
Formula I
##STR00001##
where
[0071] R.sup.1 is independently selected from monovalent reactive
groups, monovalent alkyl groups, or monovalent aryl groups, any of
the foregoing which may further comprise functionality selected
from hydroxy, amino, oxa, carboxy, alkyl carboxy, alkoxy, amido,
carbamate, carbonate, halogen or combinations thereof; and
monovalent siloxane chains comprising 1-100 Si--O repeat units
which may further comprise functionality selected from alkyl,
hydroxy, amino, oxa, carboxy, alkyl carboxy, alkoxy, amido,
carbamate, halogen or combinations thereof;
[0072] where b=0 to 500, where it is understood that when b is
other than 0, b is a distribution having a mode equal to a stated
value;
[0073] wherein at least one R.sup.1 comprises a monovalent reactive
group, and in some examples between one and 3 R.sup.1 comprise
monovalent reactive groups.
[0074] As used herein "monovalent reactive groups" are groups that
may undergo free radical and/or cationic polymerization.
Non-limiting examples of free radical reactive groups include
(meth)acrylates, styryls, vinyls, vinyl ethers,
C.sub.1-6alkyl(meth)acrylates, (meth)acrylamides,
C.sub.1-6alkyl(meth)acrylamides, N-vinyllactams, N-vinylamides,
C.sub.2-12alkenyls, C.sub.2-12alkenylphenyls,
C.sub.2-12alkenylnaphthyls, C.sub.2-6alkenylphenylC.sub.1-6alkyls,
O-vinylcarbamates and O-vinylcarbonates. Non-limiting examples of
cationic reactive groups include vinyl ethers or epoxide groups and
mixtures thereof. In one embodiment the free radical reactive
groups comprises (meth)acrylate, acryloxy, (meth)acrylamide, and
mixtures thereof.
[0075] Suitable monovalent alkyl and aryl groups include
unsubstituted monovalent C.sub.1 to C.sub.16alkyl groups,
C.sub.6-C.sub.14 aryl groups, such as substituted and unsubstituted
methyl, ethyl, propyl, butyl, 2-hydroxypropyl, propoxypropyl,
polyethyleneoxypropyl, combinations thereof and the like.
[0076] In one example, b is zero, one R.sup.1 is a monovalent
reactive group, and at least 3 R.sup.1 are selected from monovalent
alkyl groups having one to 16 carbon atoms, and in another example
from monovalent alkyl groups having one to 6 carbon atoms.
Non-limiting examples of silicone components of this embodiment
include
2-methyl-,2-hydroxy-3-[3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]disi-
loxanyl]propoxy]propyl ester ("SiGMA"),
2-hydroxy-3-methacryloxypropyloxypropyl-tris
(trimethylsiloxy)silane,
3-methacryloxypropyltris(trimethylsiloxy)silane ("TRIS"),
3-methacryloxypropylbis(trimethylsiloxy)methylsilane and
3-methacryloxypropylpentamethyl disiloxane.
[0077] In another example, b is 2 to 20, 3 to 15 or in some
examples 3 to 10; at least one terminal R.sup.1 comprises a
monovalent reactive group and the remaining R.sup.1 are selected
from monovalent alkyl groups having 1 to 16 carbon atoms, and in
another embodiment from monovalent alkyl groups having 1 to 6
carbon atoms. In yet another embodiment, b is 3 to 15, one terminal
R.sup.1 comprises a monovalent reactive group, the other terminal
R.sup.1 comprises a monovalent alkyl group having 1 to 6 carbon
atoms and the remaining R.sup.1 comprise monovalent alkyl group
having 1 to 3 carbon atoms. Non-limiting examples of silicone
components of this embodiment include
(mono-(2-hydroxy-3-methacryloxypropyl)-propyl ether terminated
polydimethylsiloxane (400-1000 MW)) ("OH-mPDMS"),
monomethacryloxypropyl terminated mono-n-butyl terminated
polydimethylsiloxanes (800-1000 MW), ("mPDMS").
[0078] In another example, b is 5 to 400 or from 10 to 300, both
terminal R.sup.1 comprise monovalent reactive groups and the
remaining R.sup.1 are independently selected from monovalent alkyl
groups having 1 to 18 carbon atoms, which may have ether linkages
between carbon atoms and may further comprise halogen.
[0079] In one example, where a silicone hydrogel lens is desired,
the lens of the present invention will be made from a reactive
mixture comprising at least about 20 and preferably between about
20 and 70% wt silicone containing components based on total weight
of reactive monomer components from which the polymer is made.
[0080] In another embodiment, one to four R.sup.1 comprises a vinyl
carbonate or carbamate of the formula:
##STR00002##
[0081] wherein: Y denotes O--, S-- or NH--;
R denotes, hydrogen or methyl; d is 1, 2, 3 or 4; and q is 0 or
1.
[0082] The silicone-containing vinyl carbonate or vinyl carbamate
monomers specifically include:
1,3-bis[4-(vinyloxycarbonyloxy)but-1-yl]tetramethyl-disiloxane;
3-(vinyloxycarbonylthio) propyl-[tris (trimethylsiloxy)silane];
3-[tris(trimethylsiloxy)silyl] propyl allyl carbamate;
3-[tris(trimethylsiloxy)silyl] propyl vinyl carbamate;
trimethylsilylethyl vinyl carbonate; trimethylsilylmethyl vinyl
carbonate, and
##STR00003##
[0083] Where biomedical devices with modulus below about 200 are
desired, only one R.sup.1 shall comprise a monovalent reactive
group and no more than two of the remaining R.sup.1 groups will
comprise monovalent siloxane groups.
[0084] Another class of silicone-containing components includes
polyurethane macromers of the following formulae:
(*D*A*D*G).sub.a*D*D*E.sup.1;
E(*D*G*D*A).sub.a*D*G*D*E.sup.1 or;
E(*D*A*D*G).sub.a*D*A*D*E.sup.1 Formulae IV-VI
wherein:
[0085] D denotes an alkyl diradical, an alkyl cycloalkyl diradical,
a cycloalkyl diradical, an aryl diradical or an alkylaryl diradical
having 6 to 30 carbon atoms,
[0086] G denotes an alkyl diradical, a cycloalkyl diradical, an
alkyl cycloalkyl diradical, an aryl diradical or an alkylaryl
diradical having 1 to 40 carbon atoms and which may contain ether,
thio or amine linkages in the main chain;
[0087] * denotes a urethane or ureido linkage;
[0088] .sub.a is at least 1;
[0089] A denotes a divalent polymeric radical of formula:
##STR00004##
R11 independently denotes an alkyl or fluoro-substituted alkyl
group having 1 to 10 carbon atoms, which may contain ether linkages
between carbon atoms; y is at least 1; and p provides a moiety
weight of 400 to 10,000; each of E and E1 independently denotes a
polymerizable unsaturated organic radical represented by
formula:
##STR00005##
wherein: R12 is hydrogen or methyl; R13 is hydrogen, an alkyl
radical having 1 to 6 carbon atoms, or a --CO--Y--R15 radical
wherein Y is --O--, Y--S-- or --NH--; R14 is a divalent radical
having 1 to 12 carbon atoms; X denotes --CO-- or --OCO--; Z denotes
--O-- or --NH--; Ar denotes an aromatic radical having 6 to 30
carbon atoms; w is 0 to 6; x is 0 or 1; y is 0 or 1; and z is 0 or
1.
[0090] A preferred silicone-containing component is a polyurethane
macromer represented by the following formula:
##STR00006##
[0091] wherein R16 is a diradical of a diisocyanate after removal
of the isocyanate group, such as the diradical of isophorone
diisocyanate. Another suitable silicone containing macromer is
compound of formula X (in which x+y is a number in the range of 10
to 30) formed by the reaction of fluoroether, hydroxy-terminated
polydimethylsiloxane, isophorone diisocyanate and
isocyanatoethylmethacrylate.
##STR00007##
[0092] Other silicone containing components suitable for use in
this invention include macromers containing polysiloxane,
polyalkylene ether, diisocyanate, polyfluorinated hydrocarbon,
polyfluorinated ether and polysaccharide groups; polysiloxanes with
a polar fluorinated graft or side group having a hydrogen atom
attached to a terminal difluoro-substituted carbon atom;
hydrophilic siloxanyl methacrylates containing ether and siloxanyl
linkages and crosslinkable monomers containing polyether and
polysiloxanyl groups. Any of the foregoing polysiloxanes may also
be used as the silicone containing component in the present
invention.
[0093] Formulations of the skirt materials as have been describe
may be configured to create a skirt layer that has structural
strength to maintain channels of various sizes while being worn
upon a user's eyes. In some examples, the channels may be molded
into the skirt as it is formed. In other examples, the channels may
be cut or eroded from the molded material. The skirt material may
also be configured so that it has an optical index of refraction
that closely matches that of tear fluid for an average human user.
Thus, the presence of molding features, which may occur in the
optic zone of the aforementioned examples of advanced contact
lenses may be rendered non optically active when they fill with
tear fluid after being placed upon the user's eyes. As mentioned
previously, various shapes and profiles of the channels may be
formed for different purposes such as enhancing directional flow of
fluids within the channels.
[0094] The methods and apparatus to enhance oxygenation in regions
proximate to an electroactive component in a biomedical device may
be designed and incorporated into numerous other types of
biomedical devices. The biomedical devices may be, for example,
implantable electronic devices, such as pacemakers and micro-energy
harvesters, electronic pills for monitoring and/or testing a
biological function, surgical devices with active components,
ophthalmic devices, and the like.
[0095] Specific examples have been described to illustrate
embodiments for the formation, methods of formation, and apparatus
of formation of biocompatible devices to enhance levels of oxygen
in regions of tissue of a user of the electroactive biomedical
device. These examples are for illustration and are not intended to
limit the scope of the claims in any manner. Accordingly, the
description is intended to embrace all embodiments that may be
apparent to those skilled in the art.
* * * * *