U.S. patent application number 16/595846 was filed with the patent office on 2020-01-30 for contact lens for increasing tear production.
The applicant listed for this patent is Oculeve, Inc.. Invention is credited to Douglas Michael Ackermann, Anand Doraiswamy, Manfred Franke, Daniel N. Hamilton, James Donald Loudin.
Application Number | 20200030615 16/595846 |
Document ID | / |
Family ID | 55761600 |
Filed Date | 2020-01-30 |
United States Patent
Application |
20200030615 |
Kind Code |
A1 |
Loudin; James Donald ; et
al. |
January 30, 2020 |
CONTACT LENS FOR INCREASING TEAR PRODUCTION
Abstract
Described here are devices, systems, and methods for increasing
tear production by stimulating the cornea, conjunctiva, and/or
subconjunctiva. In some variations, the devices may be in the form
of a contact lens. The contact lens may comprise a lens body and a
stimulator chip, where the stimulator chip is embedded in the lens
body. An external power source wirelessly transmits energy to the
stimulator chip, where the stimulator chip may convert the energy
to an electric waveform to stimulate the cornea, conjunctiva,
and/or subconjunctiva. Stimulation may activate the lacrimal reflex
to increase tear production. The devices and systems for increasing
tear production may be used in methods of treating dry eye,
reducing the symptoms of tired eye, increasing comfort for contact
lens wearers, and extending the number of years a contact lens user
can wear contacts. Also described are methods of manufacturing a
contact lens.
Inventors: |
Loudin; James Donald;
(Houston, TX) ; Franke; Manfred; (Redwood City,
CA) ; Hamilton; Daniel N.; (Napa, CA) ;
Doraiswamy; Anand; (San Francisco, CA) ; Ackermann;
Douglas Michael; (San Francisco, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oculeve, Inc. |
San Francisco |
CA |
US |
|
|
Family ID: |
55761600 |
Appl. No.: |
16/595846 |
Filed: |
October 8, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15699905 |
Sep 8, 2017 |
|
|
|
16595846 |
|
|
|
|
14920847 |
Oct 22, 2015 |
9764150 |
|
|
15699905 |
|
|
|
|
62067395 |
Oct 22, 2014 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29D 11/00826 20130101;
A61N 1/36046 20130101; A61N 1/36121 20130101; A61N 1/3606 20130101;
A61N 1/3787 20130101; B29D 11/00038 20130101; A61N 1/3756
20130101 |
International
Class: |
A61N 1/378 20060101
A61N001/378; A61N 1/375 20060101 A61N001/375; A61N 1/36 20060101
A61N001/36; B29D 11/00 20060101 B29D011/00 |
Claims
1-20. (canceled)
21. A method of treating dry eye disease in an eye of a subject,
comprising: receiving, by a stimulator, energy from an external
power source, the stimulator configured to be positioned in a
subconjunctival space of the eye and deliver a stimulus to a
lacrimal nerve for increasing tear production, the stimulator
comprising: a photodiode for receiving the energy from the external
power source to activate the stimulator, the photodiode configured
to convert the energy to the stimulus; and delivering, from the
stimulator, the stimulus to the lacrimal nerve of the subject to
cause an increase in tear production, thereby treating the dry eye
disease in the subject.
22. The method of claim 21, further comprising: periodically
replacing the stimulator in the eye of the subject, the replacing
including removing the stimulator from a first location in the eye
and placing a new stimulator in a second location in the eye.
23. The method of claim 21, wherein the external power source
comprises a laser diode.
24. The method of claim 21, wherein the photodiode receives light
from the external power source, the light comprising wavelengths
between approximately 880 nm and 930 nm.
25. The method of claim 21, wherein the external power source
comprises an infrared light-emitting diode.
26. The method of claim 21, wherein the stimulator comprises one or
more anchors configured to be pushed into the sclera to secure the
stimulator to the sclera.
27. The method of claim 26, wherein each of the one or more anchors
comprises a length between approximately 50 microns and
approximately 100 microns.
28. The method of claim 26, wherein the one or more anchors
comprises one or more of an angled pick and a nail.
29. The method of claim 21, wherein the stimulator further
comprises an atraumatic and non-irritating coating.
30. The method of claim 29, wherein the coating comprises a
hydrogel configured to allow for ionic conduction.
31. A device for treating dry eye disease in an eye of a subject,
the device comprising: a stimulator configured to increase tear
production in the eye of the subject by delivering a stimulus to a
lacrimal nerve of the subject thereby treating the dry eye disease,
the stimulator comprising: a photodiode configured to receive
energy from an external power source and convert the energy to the
stimulus.
32. The device of claim 31, wherein the stimulator is configured to
be positioned in a subconjunctival space of the eye of the
subject.
33. The device of claim 31, wherein the external power source
comprises a laser diode.
34. The device of claim 31, wherein the photodiode receives light
from the external power source, the light comprising wavelengths
between approximately 880 nm and 930 nm.
35. The device of claim 31, wherein the external power source
comprises an infrared light-emitting diode.
36. The device of claim 31, wherein the external power source
comprises an optical modifier to produce non-collimated light.
37. The device of claim 32, wherein the stimulator comprises one or
more anchors configured to be pushed into the sclera to secure the
stimulator to the sclera.
38. The device of claim 37, wherein each of the one or more anchors
comprises a length between approximately 50 microns and
approximately 100 microns.
39. The device of claim 37, wherein the one or more anchors
comprises one or more of an angled pick and a nail.
40. The device of claim 31, wherein the stimulator further
comprises an atraumatic and non-irritating coating.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/699,905, filed Sep. 8, 2017, and titled
"IMPLANTABLE DEVICE FOR INCREASING TEAR PRODUCTION," which is a
divisional of U.S. patent application Ser. No. 14/920,847, filed
Oct. 22, 2015, and titled "CONTACT LENS FOR INCREASING TEAR
PRODUCTION," which claims priority to U.S. Provisional Patent
Application No. 62/067,395, filed on Oct. 22, 2014, and titled
"CONTACT LENS FOR INCREASING TEAR PRODUCTION," each of which is
hereby incorporated by reference in its entirety.
FIELD
[0002] The present disclosure relates generally to stimulation
devices, systems, and methods of use thereof. The stimulation
systems may be used to stimulate the cornea and/or conjunctiva
and/or subconjunctiva of the eye to increase tear production in the
treatment of one or more indications, such as dry eye.
BACKGROUND
[0003] Dry eye is a condition that affects millions of people. More
than 40 million people in North America have some form of dry eye,
and many millions more suffer worldwide. Dry eye results from the
disruption of the natural tear film on the surface of the eye, and
can result in ocular discomfort, visual disturbance and a reduction
in vision-related quality of life. Activities of daily living such
as driving, computer use, housework, and reading have also been
shown to be negatively impacted by dry eye. Patients with severe
cases of dry eye are at risk for serious ocular health deficiencies
such as corneal ulceration, and can experience a quality of life
deficiency comparable to that of moderate-severe angina.
[0004] Dry Eye Disease ("DED") is a clinical condition of the eye.
DED is progressive in nature, and fundamentally results from
insufficient tear coverage on the surface of the eye. This poor
tear coverage prevents healthy gas exchange and nutrient transport
for the ocular surface, promotes cellular desiccation, and creates
a poor refractive surface for vision. Poor tear coverage typically
results from: 1) insufficient aqueous tear production from the
lacrimal glands (e.g. secondary to post-menopausal hormonal
deficiency, autoimmune disease, LASIK surgery, etc.), and/or 2)
excessive evaporation of aqueous tear resulting from dysfunction of
the meibomian glands. Low tear volume causes a hyperosmolar
environment that induces an inflamed state of the ocular surface.
This inflammatory response induces apoptosis of the surface cells,
which in turn prevents proper distribution of the tear film on the
ocular surface so that any given tear volume is rendered less
effective. This initiates a vicious cycle where more inflammation
can ensue, causing more surface cell damage, etc.
[0005] External factors that are not clinically based may also
contribute to dry eye. These factors can include medications,
dehydration, and environmental pollutants. Contact lenses,
particularly soft contact lenses, are also known to cause or
exacerbate the symptoms of dry eye. The contact lenses continually
absorb water from the surface of the tear film in order to keep
hydrated, leading to dryness of the eye. Dry eye can also be a
symptom of the condition commonly known as "tired eye." During
extended periods of focused, intense use, such as heavy computer
use and long distance driving, the eyes strain and blink less
frequently, which can lead to insufficient lubrication of the eyes
(i.e., dry eye).
[0006] There is a wide spectrum of treatments for dry eye, although
without substantial efficacy for treatment of the condition.
Treatment options include: artificial tear substitutes, ointments,
gels, warm compresses, environmental modification, topical
cyclosporine, omega-3 fatty acid supplements, punctal plugs, and
moisture chamber goggles. Patients with severe disease may further
be treated with punctal cautery, systemic cholinergic agonists,
systemic anti-inflammatory agents, mucolytic agents, autologous
serum tears, PROSE scleral contact lenses, and tarsorrhaphy.
Despite these treatment options, dry eye continues to be considered
one of the most poorly treated diseases in ophthalmology.
Accordingly, it would be desirable to have a more effective
treatment for dry eye.
BRIEF SUMMARY
[0007] Described here are devices, systems, and methods for
increasing tear production by stimulating the cornea, conjunctiva,
and/or subconjunctiva. Generally, the devices and systems may be
configured to electrically stimulate the cornea and/or conjunctiva
and/or subconjunctiva. In some variations, the devices may comprise
a stimulator chip. An external power source may wirelessly transmit
energy to the stimulator chip, where the stimulator chip may
convert the energy transmitted to an electric waveform and
electrically stimulate the cornea, conjunctiva and/or
subconjunctiva. Stimulation may activate reflex pathways to
increase tear production. The devices and systems for increasing
tear production may be used in methods of treating dry eye,
reducing the symptoms of tired eye, increasing comfort for contact
lens wearers, and extending the number of years a contact lens user
can wear contacts. Also described are methods of manufacturing a
contact lens, where the contact lens is configured to increase tear
production by stimulating the cornea, conjunctiva, and/or
subconjunctiva.
[0008] In some variations, the devices described here may comprise
lens devices for increasing tear production by stimulating the
cornea, conjunctiva, and/or subconjunctiva of a subject. The
devices may be in the form of a contact lens for placement on the
cornea/conjunctiva of the eye. The contact lens may comprise a lens
body and a stimulator chip, where the stimulator chip is within the
lens body. Energy transmitted from the external power source to the
stimulator chip may be converted to electrically stimulate the
cornea, conjunctiva, and/or subconjunctiva. The lacrimal pathway
may be initiated with activating sensory components in the cornea,
conjunctiva, subconjunctiva, or surrounding orbital tissue.
Stimulation may activate the lacrimal reflex to increase tear
production.
[0009] In some variations, the devices described here may comprise
implantable devices for increasing tear production by stimulating
the cornea, conjunctiva, and/or subconjunctiva of a subject. In
some variations, the device may be in the form of an implantable
device comprising a stimulator chip. The implantable device may
utilize reflex pathways to activate the lacrimal gland, and in some
cases the accessory glands, such as krause, zeiss, and meibomian
glands, to increase tear production and tear quality. The
implantable device may be placed subconjunctivally.
[0010] In some variations, the systems described here comprise
systems for increasing tear production by stimulating the cornea,
conjunctiva, and/or subconjunctiva of a subject. In some
variations, the system may comprise a device having a stimulator
chip and an external power source. The external power source may be
handheld or mountable for mounting to locations adjacent to where a
patient may look for extended periods of time (e.g., a computer
monitor, car windshield, television, etc.). The stimulator chip may
receive wireless energy from the external power source and provide
an electric stimulation waveform to the corneal and/or conjunctival
innervation of the eye to increase tear production. In some
variations, the external power source may be a laser diode or a
light-emitting diode (LED), which may in some instances emit
infrared (IR) light.
[0011] In some variations, the methods described here may comprise
methods for increasing tear production in a subject. In some
variations, the methods for increasing tear production may be used
for treating DED caused by clinical factors, such as dysfunction of
the lacrimal and/or meibomian glands. The treatment may also be for
dry eye caused by external factors, such as medications,
dehydration, and environmental pollutants. In some variations, the
methods for increasing tear production may be for increasing
comfort for contact lens wearers. In some variations, the methods
for increasing tear production may be for reducing the symptoms of
tired eye in patients not diagnosed as having DED. In some
variations, the methods for increasing tear production may be for
extending the number of years a contact lens user can wear
contacts. The methods may comprise the step of stimulating the
cornea, conjunctiva, and/or subconjunctiva to activate the reflex
pathway and increase lacrimation.
[0012] In some variations, the methods described here comprise
methods of manufacturing a contact lens configured to increase tear
production by stimulating the cornea, conjunctiva, and/or
subconjunctiva. The method of manufacturing a contact lens may
comprise the step of embedding a stimulator chip in a lens body by
sheet casting or rod casting. The method may further comprise the
step of lathe cutting the casting to a desired shape. In some
variations, the method of manufacturing a contact lens may comprise
embedding a stimulator chip in a lens body and shaping the lens
body by direct cast molding.
[0013] In some variations, the devices described here comprise a
contact lens for increasing tear production in an eye of a subject.
In some variations, the contact lens comprises a lens body
configured for placement on a surface of the eye, and a stimulator
chip configured to stimulate a cornea or a conjunctiva of the eye,
where the stimulator chip is embedded within the lens body. In some
variations, the lens body is a corrective lens. In some of these
variations, the corrective lens is toric, aspheric, multifocal,
diffractive, or scleral. In some variations, the lens body is
non-corrective or non-refractive and has a zero power. In some
variations, the lens body has a posterior surface configured to
contact the conjunctiva of the eye, and the stimulator chip is
embedded in the lens body within 20 microns of the posterior
surface. In some variations, the stimulator chip is embedded in a
portion of the lens body that is configured to cover an iris of the
eye when the lens body is placed on the surface of the eye. In some
variations, the stimulator chip is embedded in a portion of the
lens body that is configured to be in front of an iris of the eye
when the lens body is placed on the cornea of the eye. In some
variations, the contact lens comprises a counterweight located
approximately 180 degrees from the stimulator chip. In some of
these variations, the counterweight is a second stimulator chip. In
some variations, the contact lens comprises one or more weights for
minimizing rotation of the contact lens. In some of these
variations, the one or more weights is a second stimulator chip. In
some variations, the stimulator chip is configured to receive
energy wirelessly from an external power source and to convert the
energy to a stimulation signal for electrically stimulating the
cornea or the conjunctiva. In some of these variations, the
stimulator chip comprises a power receiver configured to receive
the energy wirelessly and to convert the energy to an electric
signal. In some of these variations, the stimulator chip further
comprises a signal conditioning unit configured to receive the
electric signal and to modify the electric signal into an electric
output. In some of these variations, modifying the electric signal
comprises modifying one or more of a frequency, a shape, and an
amplitude of the electric signal. In some variations, the
stimulator chip further comprises electrode contacts configured to
deliver the electric output to the cornea or the conjunctiva. In
some of these variations, the electric output has a frequency that
varies over time. In others of these variations, the electric
output has a pulse width that varies over time. In some variations,
the stimulator chip comprises a photodiode. In some variations, the
stimulator chip comprises an integrated circuit. In some
variations, the stimulator chip has a thickness between
approximately 5 microns and 100 microns. In some of these
variations, the thickness of the stimulator chip is approximately
20 microns.
[0014] In some variations, the systems described here are for
increasing tear production in an eye of a subject. In some
variations, the systems comprise a device configured for placement
on a cornea, or in a subconjunctiva of the eye, where the device
comprises a stimulator chip configured to stimulate the cornea or a
conjunctiva of the eye, and an external power source for
transmitting energy wirelessly to the stimulator chip to activate
the stimulator chip. In some variations, the external power source
is handheld. In other variations, the external power source is
mountable. In some variations, the external power source comprises
a laser diode. In some of these variations, the laser diode
produces light comprising wavelengths between approximately 880 nm
and 930 nm. In some variations, the external power source comprises
an infrared light-emitting diode. In other variations, the external
power source comprises an optical modifier to produce
non-collimated light. In some of these variations, the optical
modifier comprises a condenser lens and a microlens array. In some
variations, the stimulator chip comprises a photodiode.
[0015] Also described here are methods of increasing tear
production in a subject. In some variations, the methods comprise
transmitting energy wirelessly from an external power source to a
stimulator chip, where the stimulator chip is located in a
subconjunctival space of an eye of the subject or is embedded in a
contact lens worn by the subject, and delivering a stimulus from
the stimulator chip to a conjunctiva or a cornea of the eye to
produce tears. In some variations, the stimulator chip comprises a
photodiode, and the external power source comprises a light source.
In some of these variations, the light source comprises a laser
diode. In other of these variations, the light source comprises an
infrared light-emitting diode. In some variations, the method
further comprises moving the eye to expose the photodiode to the
light source. In some variations, the external power source is
fixed to a location selected from the group consisting of a
computer monitor, a car windshield, a television, and a forward
face of a smart phone or a tablet. In some variations, the
stimulator chip is within an implantable device located in the
subconjunctival space of the eye. In some of these variations, the
implantable device is secured in the subconjunctival space of the
eye by one or more anchors. In some variations, the method further
comprises periodically replacing the implantable device. In some of
these variations, replacing the implantable device comprises
removing the existing implantable device from a first location and
placing a new implantable device in a second location. In some
variations, the subject has dry eye, and the method of increasing
tear production is used to treat the dry eye. In some variations,
the subject is at an increased risk of developing dry eye, and the
method of increasing tear production is used for prophylactic
treatment of dry eye. In some variations, the subject has ocular
allergies, and method of increasing tear production is used to
treat the ocular allergies. In some variations, the subject wears
contact lenses, and the method of increasing tear production is
used for increasing comfort of wearing contact lenses. In some
variations, the subject wears contact lenses, and the method of
increasing tear production is used for extending a time period for
which the subject can comfortably wear contact lenses. In some
variations, the subject wears contact lenses, and the method of
increasing tear production is used for extending a number of years
for which the subject can wear contact lenses. In some variations,
the subject has tired eye, and the method of increasing tear
production is used for reducing symptoms of tired eye.
[0016] Also described here are methods for manufacturing a contact
lens configured to treat dry eye. In some variations, the method
comprises embedding a stimulator chip in a lens body, and shaping
the lens body. In some variations, embedding comprises sheet
casting. In other variations, embedding comprises rod casting. In
some variations, shaping comprises lathe cutting. In some
variations, the method comprises cast molding. In some variations,
the contact lens has a posterior surface configured to contact a
conjunctiva of an eye, and the stimulator chip is embedded in the
lens body proximate to the posterior surface at a distance
sufficient to allow for effective stimulation of a cornea and/or
the conjunctiva of the eye by the stimulator chip.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows a cut-away side view of an illustrative
variation of a contact lens with a stimulator chip;
[0018] FIG. 2 shows a front view of an illustrative variation of a
contact lens having a stimulator chip and a counterweight;
[0019] FIG. 3 shows an illustrative implantable device implanted in
a position behind the lower eyelid;
[0020] FIG. 4 shows a block diagram illustrating a method of
increasing tear production using a stimulator chip;
[0021] FIG. 5 shows an illustrative variation of a stimulator
chip;
[0022] FIG. 6 shows an illustrative variation of the spectral
response of a photodiode;
[0023] FIG. 7 shows an illustrative variation of an external power
source comprising an optical modifier to produce non-collimated
light;
[0024] FIG. 8 shows an illustrative variation of a system
comprising a contact lens with a stimulator chip and a computer
monitor-mounted external power source;
[0025] FIGS. 9A-9D show an illustrative variation of a method of
manufacturing a contact lens using sheet casting;
[0026] FIGS. 10A-10D show an illustrative variation of a method of
manufacturing a contact lens using rod casting;
[0027] FIGS. 11A-11C show an illustrative variation of the shaping
of a contact lens from button form to a meniscus lens using lathe
cutting;
[0028] FIGS. 12A-12D show an illustrative variation of a method of
manufacturing a contact lens using cast molding.
DETAILED DESCRIPTION
[0029] Described here are devices, systems, and methods for
increasing tear production by stimulating the cornea, conjunctiva,
and/or subconjunctiva. The device may be a contact lens or an
implantable device, which may comprise a stimulator chip. The
system may comprise the contact lens or implantable device and an
external power source that may wirelessly transmit energy to the
stimulator chip. The stimulator chip may convert the energy
transmitted to an electric waveform, which may be delivered to a
subject to electrically stimulate the cornea, conjunctiva, and/or
subconjunctiva. This may in turn activate the reflex pathways and
increase tear production.
[0030] The devices and systems for increasing tear production
described here may be used in methods of treating dry eye caused by
clinical and/or external factors. They may also be used in methods
of reducing the symptoms of tired eye, increasing comfort for
contact lens wearers, and extending the number of years a contact
lens user can wear contacts. Also described are methods of
manufacturing a contact lens, where the contact lens is configured
to increase tear production by stimulating the cornea and/or
conjunctiva.
Devices
[0031] The devices described here may be for placement on the
cornea or for placement in the subconjunctiva of the eye. The
devices may comprise a stimulator chip for electrically stimulating
the cornea and/or conjunctiva to increase lacrimation in patients
suffering from dry eye, tired eye, and other conditions.
Contact Lens
[0032] As shown in FIG. 1, device 100 is in the form a contact lens
110 for placement on the cornea/conjunctiva of the eye. The contact
lens 110 has a lens body 112 made from a biomaterial. The
biomaterial can be any optically clear and biologically compatible
material. Classifications of acceptable biomaterials include, but
are not limited to: hydrophilic acrylates, hydrophobic acrylates,
rigid poly(methyl methacrylate) (PMMA), and polyurethanes. Also
acceptable are hydrogel materials, including but not limited to:
silicone hydrogels, silicone acrylates (SAs), fluoro-silicone
acrylates, and various gas-permeable materials. The biomaterial may
be ionic or non-ionic, and may have a high water content or low
water content, such as ranging from about 30% to about 70%. In some
variations, the contact lens may have a monoblock lens body. In
other variations, the contact lens may have a hybrid lens body
comprising a soft, pliable, optically clear center portion and a
rigid perimeter portion made from a rigid gas permeable
material.
[0033] The contact lens may be corrective having a power specific
to the patient's needs. The contact lens may also be a toric,
aspheric, multifocal, diffractive, scleral, or other type of
corrective contact lens. Alternatively, the lens may be
non-corrective/refractive (i.e., zero power) for patients who do
not require corrective lenses but suffer from dry eye, tired eye,
or other eye conditions. The lens also may be a bandage contact
lens for protecting and healing the eye and increasing comfort for
patients with damaged or compromised corneas.
[0034] Contact lens 110 comprises a stimulator chip 114 within the
lens body 112. Stimulator chip 114 may be configured to convert
wireless energy transmitted from an outside source to an electric
waveform for electrically stimulating the cornea/conjunctiva.
Stimulator chip 114 is embedded in the lens body 112 and is
positioned close to the posterior surface 116 adjacent to the eye.
Close proximity of the stimulator chip to the eye surface may allow
for effective stimulation of the cornea and/or conjunctiva.
Accordingly, in some variations, the stimulator chip may be within
5 microns, within 10 microns, or within 10-20 microns of the
posterior surface of the lens. Larger stimulators may be positioned
further from the posterior surface. In other variations, the
stimulator chip may be within 50-100 microns of the posterior
surface. In other variations, such as with hybrid lens bodies
described herein, the stimulator chip may be mounted directly to
the surface of the lens body. The stimulator chip may be located in
a number of positions in the lens body, but it may be desirable for
the stimulator chip to be located in the portion of the lens body
that covers the iris of the eye when inserted, so as to avoid
blocking the visual axis.
[0035] In some instances it may be desirable that the contact lens
be rotationally unstable to allow repositioning of the stimulator
chip when blinking. This may reduce accommodation and habituation
to the stimulus. In one variation, a single stimulator chip
embedded in the lens body is light enough in weight to not
unbalance the contact lens or prevent repositioning. In another
variation, shown in FIG. 2, a counterweight 216 is located
approximately 180 degrees from a first stimulator chip 214 in order
to balance the weight and prevent the first stimulator chip 214
from weighing down and inhibiting rotation of contact lens 210. The
counterweight 216 may be, for example, another stimulator chip, but
may also be an inactive chip or any suitable object having
appropriate weight and size.
[0036] However, in other instances such rotational instability may
be undesirable. For example, contact lenses used for astigmatism
are generally toric lenses having different optical power and focal
length in two perpendicular orientations. In these cases, rotation
of the lens may negatively affect vision, and therefore may not be
desirable. In some variations for addressing astigmatism, one, two,
or more inactive chips, or other weights, may be placed in the
lower portion of the lens body in order to help the lens find a
specific orientation and minimize rotation.
Implantable Device
[0037] In another variation, the device may be in the form of an
implantable device. The implantable device may comprise a
stimulator chip that is implanted within the eye and may utilize
reflex pathways to provide activation to the lacrimal gland to
increase tear production, and in some cases to provide activation
of the accessory glands.
[0038] The implantable device may in some instances be placed
subconjunctivally. The implantable device may be implanted in any
location in the subconjunctiva where the stimulator chip can be
exposed to energy transmission from an external power source. As
shown in FIG. 3, it may be preferable for an implantable device 310
to be implanted in the subconjunctiva behind an eyelid (e.g., the
lower eyelid) to avoid cosmetic impact. In this location, the
implantable device 310 may be hidden when the subject looks
straight ahead or side-to-side, but may become exposed when looking
up. In other variations, the implantable device may be implanted
such that it is visible when the subject looks straight ahead or
side-to-side. In these cases, the implant may be configured with a
decorative shape and/or distinct color (e.g., a red heart), so as
to appear to be eye jewelry.
[0039] Because the conjunctiva defines an open space between it and
the cornea, an implantable device inserted in the subconjunctival
space may tend to migrate. Accordingly, the implantable device may
comprise one or more fixation features to secure it in place. In
some variations, fixation features may include one or multiple feet
extending from the device. The feet may measure approximately
50-100 microns in length. In some instances, the feet may be pushed
into the sclera for anchorage. Fixation features may also include
an angled pick or nail for holding the device in place,
biocompatible glue for initial fixation, or any other suitable
anchoring feature.
[0040] The stimulator chip may have a coating of a thickness that
allows the stimulation device to be atraumatic and non-irritating
when implanted in the eye, but close enough to the conjunctiva to
stimulate the nerves therein. Close proximity of the stimulator
chip to the eye surface may allow for effective stimulation of the
cornea, conjunctiva, and/or subconjunctiva, while exposure may
result in a foreign body sensation and irritation. Accordingly, in
some variations, the stimulator chip may have a coating that is
between about 5 microns and about 20 microns thick. In some
variations, a coating may comprise a hydrogel in order to allow for
ionic conduction.
Stimulator Chip
[0041] FIG. 4 shows a block diagram illustrating how tear
production may be increased using a stimulator chip as described
herein. Generally, an external power 401 source may transmit
wireless energy to a stimulator chip 406. The stimulator chip 406
may then convert the energy to a stimulation signal E.sub.out
comprising an electric waveform, which may be delivered to a
subject for electrically stimulating the cornea/conjunctiva
408.
[0042] More specifically, the stimulator chip 406 may comprise a
power receiver 403 and a signal conditioning unit 405. The power
receiver 403 may be supplied with wireless energy from the external
power source 401, and may convert the wireless energy to an
electric signal E.sub.in. The signal conditioning unit 405 may
receive the electric signal E.sub.in and then modify the electric
signal E.sub.in into the desired electric output E.sub.out. The
signal conditioning unit 405 may modify one or more of the signal's
frequency, shape, and amplitude in any suitable manner (e.g., using
resistive and capacitive elements, amplifiers). The electric output
E.sub.out may be a desired stimulation signal and may be delivered
via electrode contacts to the cornea/conjunctiva 408 to activate
lacrimation. While the variation of the system described with
respect to FIG. 4 comprises a signal conditioning unit to modify
the signal to the desired electrical stimulus, it should
appreciated that in some variations, the signal may additionally or
alternatively be manipulated using the external power source (e.g.,
by pulsing the power source in a particular pattern). With
photovoltaics, for the example, manipulation of the signal may be
done entirely externally by manipulation of the external power
source.
[0043] In some variations, the stimulator chip may comprise one or
more photodiodes, which act as both the power receiver and the
signal conditioning unit. FIG. 5 shows a variation of a stimulator
chip comprising an integrated circuit 500. The integrated circuit
may be formed by semiconductor fabrication techniques on any
suitable substrate, such as but not limited to a silicon on
insulator (SOI) substrate. FIG. 5 shows an SOI semiconductor
substrate 512 having an insulator layer 514. Light pulsed at a
higher irradiance than ambient light, depicted by multiple arrows,
is transmitted to the stimulator chip, which comprises a photodiode
in region 510. The stimulation signal (i.e., the electric output)
produced may be delivered through vias 516 to electrode contacts
518, 520 for stimulating the ocular tissue. A stimulator chip
comprising a single photodiode, as in FIG. 5, may produce a voltage
of up to about 0.6 V, but it should be appreciated that if higher
voltage is desired, multiple diodes may be formed in series on the
substrate. The stimulator chip may also comprise more than two
electrodes in some variations.
[0044] The electrodes may each have dimensions (e.g., a diameter)
measuring between 50 microns and 150 microns, specifically between
75 microns and 125 microns, or more specifically approximately 100
microns. This may result in an area of neural activation of
approximately 100 microns. The electrodes may be made from any
suitable material, such as but not limited to platinum or iridium
oxide films. The stimulator chip may have a length measuring
between 0.5 mm and 1.5 mm, specifically between 0.75 mm and 1.25
mm, or more specifically approximately 1.0 mm. The stimulator chip
may have a width measuring between 0.5 mm and 1.5 mm, specifically
between 0.75 mm and 1.25 mm, or more specifically approximately 1.0
mm. The stimulator chip may have a thickness measuring between 5
microns and 100 microns, specifically between 10 microns and 50
microns, or more specifically approximately 20 microns. In some
variations, the stimulator chip measures 1.0 mm.times.1.0
mm.times.20 microns. The above-mentioned dimensions are exemplary
only, and are not limited to the ranges provided. The stimulation
chip and components thereof may be actually be larger, as their
size may be limited only by the ability for the stimulator chip to
fit within the contact lens and not block vision, while meeting the
cosmetic requirements of the patient.
External Power Source
[0045] The external power source may be configured to wirelessly
transmit energy to the stimulator chip. The external power source
may comprise an on/off switch so it can be turned off when not in
use by the patient. The external power source may be handheld or
mountable for mounting to locations adjacent to where a patient may
look for extended periods of time. Mounting locations include, but
are not limited to, a computer monitor, car windshield, television,
forward face of a smart phone, tablet, etc. In some variations, the
mounting location may be on the frame of eyeglasses. A subject
wearing a contact lens or having an implant as described herein may
activate the stimulator chip by exposing a portion of the
stimulator chip (e.g., a photodiode) to the power source. Moving
the eye (e.g., looking up) may expose the stimulator chip to the
energy transmitted by the power source.
[0046] In some variations in which the stimulator chip comprises a
photodiode, the power source may comprise a light source, such as a
laser diode. A laser diode may produce light within a relatively
narrow wavelength band. This wavelength band may be chosen to be
specific to the wavelength needed to excite the photodiode, while
also avoiding wavelengths visible to humans. The responsivity curve
of silicon-based photodiodes may end at approximately 1100 nm,
while the human eye may be unable to see high intensity infrared
light at wavelengths above approximately 850 nm. Therefore, it may
be desirable to select a laser diode producing light comprising
wavelengths in the range of approximately 880 nm to approximately
930 nm. FIG. 6 graphically shows the spectral response of an
exemplary photodiode that could be used in the current application.
In other variations, the external power source may comprise an
infrared light-emitting diode (LED).
[0047] The desired wavelength range and power of the light
transmitted by the power source may provide the energy required to
cause the photodiode to generate current, without being phototoxic
to the cornea and/or retina. To avoid harming the retina, it may be
desirable for the intensity of the source to be below the levels
known to cause damage to the retina, as specified in the American
National Standard Institute (ANSI) Standards. In some variations,
it may be desirable for the intensity of the source to be below the
intensity of sunlight. If a photodiode in a stimulator chip as
described herein has a surface area of 1 mm.sup.2, for example,
pulsing the source at a 1% duty cycle may allow for a safe power
range up to 100 mW. In some variations, the external power source
described herein may emit 10 mW, pulsed at a 1% duty cycle, which
is well within a safe range. The power that may be needed to be
delivered to the photodiode may vary by device construction. In
some variations, for example, the photodiode may require a power of
approximately 0.1 mA to approximately 2 mA to generate a desired
stimulation signal, and a light intensity of approximately 1
mW/mm.sup.2 to approximately 5 mW/mm.sup.2 may be needed to
generate this. In some variations, the photodiode may require a
power of approximately 1 mA to generate a desired stimulation
signal, and a light intensity of approximately 3 mW/mm.sup.2 may be
needed to generate this. However, it should be appreciated that the
powers and light intensities desired may vary largely depending on
implementation, and the power and intensity desired may increase
for chips comprising more than one photodiode (e.g., may in some
variations approximately double or triple for variations that
utilize two or three diodes, respectively).
[0048] It may be desirable for the output of the external light
source to be non-collimated. As shown in the diagram of FIG. 7, the
external light source 702 may comprise an optical modifier 704 to
produce non-collimated light. In some variations, the optical
modifier 704 may comprise a condenser lens 705 and microlens array
706. The external light source 701 may also in some instances
comprise a controller 703, which may modulate the output of the
light source 702 to manipulate the desired output stimulus signal,
in addition to or instead of a signal conditioning unit of a
stimulator chip. In such variations, signal conditioning may be
done almost entirely externally, and internal signal conditioning
may only limit the voltage and/or current amplitude.
[0049] By manipulating the external power source, the electric
signals delivered to the subject may be tailored for specific
treatment regimens and/or specific subjects. The waveforms may be
pulse-based or continuous. When the stimulator is configured to
deliver a continuous waveform, the waveform may be a sinusoidal in
amplitude and/or pulse-width, or quasi-sinusoidal, square-wave,
sawtooth/ramped, or triangular waveform, truncated-versions thereof
(e.g., where the waveform plateaus when a certain amplitude is
reached), or the like.
[0050] In some variations, the stimulator may be configured to vary
the frequency and/or pulse width of the waveform. This variation
may occur according to a pre-determined plan, or may be configured
to occur randomly within given parameters. For example, in some
variations the continuous waveform may be configured such that the
frequency or pulse width of the waveform varies over time (e.g.,
according to a sinusoidal function having a beat frequency). In
some instances varying the frequency and/or pulse width of a
stimulation waveform over time, or pulsing the stimulus on and off
(e.g., 1 second on/1 second off, 5 seconds on/5 seconds off), may
help reduce subject habituation (in which the subject response to
the stimulation decreases during stimulation). Additionally or
alternatively, ramping the amplitude of the stimulation waveform at
the beginning of stimulation may increase comfort. Patterning may
achieve a stronger reflex activation and thereby elicit more
tearing in both eyes from stimulation in only one eye.
[0051] When the stimulator is configured to create a pulse-based
electrical waveform, the pulses may be any suitable pulses (e.g., a
square pulse, a haversine pulse, or the like). The pulses delivered
by these waveforms may by biphasic, alternating monophasic, or
monophasic, or the like. When a pulse is biphasic, the pulse may
include a pair of single phase portions having opposite polarities
(e.g., a first phase and a charge-balancing phase having an
opposite polarity of the first phase). In some variations, it may
be desirable to configure the biphasic pulse to be charge-balanced,
so that the net charge delivered by the biphasic pulse is
approximately zero. In some variations, a biphasic pulse may be
symmetric, such that the first phase and the charge-balancing phase
have the same pulse width and amplitude. In other variations, a
biphasic pulse may be asymmetric, where the amplitude and/or pulse
width of the first pulse may differ from that of the
charge-balancing phase. Additionally, each phase of the biphasic
pulse may be either voltage-controlled or current-controlled. In
some variations, both the first phase and the charge-balancing
phase of the biphasic pulse may be current-controlled. In other
variations, both the first phase and the charge-balancing phase of
the biphasic pulse may be voltage-controlled. In still other
variations, the first phase of the biphasic pulse may be
current-controlled, and the second phase of the biphasic pulse may
be voltage-controlled, or vice-versa.
[0052] In variations where the waveform comprises a biphasic pulse,
the biphasic pulse may have any suitable frequency, pulse widths,
and amplitudes. For example, in instances where the stimulators
described here are used to treat dry eye or otherwise produce a
tearing response by stimulating the cornea and/or conjunctiva, the
stimulator may be configured to generate a biphasic pulse waveform
at a frequency between about 0.1 Hz and about 200 Hz. In some of
these variations, the frequency is preferably between about 10 Hz
and about 60 Hz. In some of these variations, the frequency is
preferably between about 25 Hz and about 35 Hz. In others of these
variations, the frequency is preferably between about 50 Hz and
about 90 Hz. In some of these variations, the frequency is
preferably between about 65 Hz and about 75 Hz. In other
variations, the frequency is preferably between about 130 Hz and
about 170 Hz. In some of these variations, the frequency is
preferably between about 145 Hz and about 155 Hz. In some
variations, high frequencies, such as those between about 145 Hz
and about 155 Hz may be too high for each pulse to
stimulate/activate the target nerves. As a result, the stimulation
may be interpreted by the patient to have an element of randomness,
which in turn may help to reduce subject habituation.
[0053] Similarly, when the stimulus is electrical and the first
phase of the biphasic pulse is current-controlled, the first phase
may preferably have an amplitude between about 10 .mu.A and 20 mA.
In some of these variations, the amplitude may be preferably
between about 0.1 mA and about 10 mA. When the first phase of the
biphasic pulse is voltage-controlled, the first phase may
preferably have an amplitude between about 10 mV and about 25 V.
Additionally, the first phase may preferably have a pulse width
between about 1 .mu.s and about 10 ms. In some of these variations,
the pulse width may preferably be between about 10 .mu.s and about
100 .mu.s. In other variations, the pulse width may preferably be
between about 100 .mu.s and about 1 ms.
[0054] When an electrical pulse waveform is an alternating
monophasic pulsed waveform, each pulse delivered by the stimulator
may have a single phase, and successive pulses may have alternating
polarities. Generally, the alternating monophasic pulses are
delivered in pairs at a given frequency (such as one or more of the
frequencies listed above, such as between 30 Hz and 50 Hz), and may
have an inter-pulse interval between the first and second pulse of
the pair (e.g., about 100 .mu.s, between 50 .mu.s and 150 .mu.s or
the like). Each pulse may be current-controlled or
voltage-controlled, and consecutive pulses need not be both
current-controlled or both voltage-controlled. In some variations
where the pulse waveform is charged-balanced, the waveform may
comprise a passive charge-balancing phase after delivery of a pair
of monophasic pulses, which may allow the waveform to compensate
for charge differences between the pulses.
[0055] As an alternative to optical coupling, power may be
transferred to the stimulator chip from the external source using
electromagnetic coupling or an electromagnetic telemetry link. For
example, in some variations, the contact lens or implant may
comprise an inductive coil and rectification circuit. In such
variations, the external power source may be manipulated to control
the frequency and pulse-width modulation of the stimulation
signal.
Systems
[0056] A system as described herein may comprise a device having a
stimulator chip and an external power source. The two components
may be structurally and functionally configured to work together to
increase tear production by stimulating the cornea, conjunctiva,
and/or subconjunctiva. The external power source may deliver power
and/or signal appropriate to activate the stimulator chip. FIG. 8
shows one variation of a system comprising a contact lens 810 with
an embedded stimulator chip 814 as described herein, and a
mountable external power source 850 mounted to a computer monitor
854. Transmission of wireless power 856 from the power source 850
to the stimulator chip 814 is illustratively shown. The distance x
between the contact lens 810 and the mounted power source 850 is
close enough for the stimulator chip 814 to receive the required
intensity for the chip to generate the desired electrical
stimulus.
Methods
[0057] The methods described here may comprise methods for treating
dry eye and increasing tear production. Also described are methods
for manufacturing a contact lens with an embedded stimulator
chip.
Treatment Methods
[0058] The methods described here may comprise methods for treating
dry eye and increasing tear production in a subject. The methods
for increasing tear production may be used to treat a number of eye
conditions and can provide immediate relief from discomfort and
pain, as well as long-term improvements to overall ocular health.
The treatment methods may involve one or more treatment regimens,
such as providing stimulation to the cornea, conjunctiva, and/or
subconjunctiva on an as-needed basis and/or according to a
pre-determined regimen.
[0059] The method may be used to treat various forms of dry eye,
including (but not limited to), chronic dry eye, episodic dry eye,
seasonal dry eye, aqueous deficient dry eye, or evaporative dry
eye. In some variations, the methods for increasing tear production
may be used for treating DED caused by clinical factors, such as
dysfunction of the lacrimal and/or meibomian glands. The treatment
may also be for dry eye caused by external factors, such as
medications, dehydration, and environmental pollutants. In some
instances, the method may be used as a prophylactic measure to
treat users who may be at an increased risk of developing dry eye,
such as subjects who will undergo or who have undergone ocular
surgery such as refractive vision correction and/or cataract
surgery. In other instances, the method may be used to treat ocular
allergies. For example, an increase in tear production may flush
out allergens and other inflammatory mediators from the eyes.
[0060] In some variations, the methods for increasing tear
production may be for increasing comfort for contact lens wearers.
The system may be used in response to discomfort in order to
decrease the discomfort associated with contact lens use. The
system may also be used in response to discomfort to extend the
time period for which an individual can comfortably wear contact
lenses. Dryness and other conditions resulting from prolonged use
of contact lenses may shorten the lifetime of contact lens use,
which is often not past the age of forty. In some variations, the
methods for increasing tear production may be for extending the
number of years a contact lens user can wear contacts.
[0061] In some variations, the methods for increasing tear
production may be for reducing the symptoms of tired eye in
patients not diagnosed as having DED. Increased tear production may
lead to more frequent blinking, which may in turn keep the eyes
lubricated and reduce feelings of heaviness and strain.
[0062] Generally, the methods may comprise placing a device with a
stimulator chip on the cornea or in the subconjunctiva of the eye
of a subject. Because the nerves innervating the superior,
inferior, and lateral portions of the conjunctiva (the supraorbital
nerve, supratrochlear nerve, infratrochlear nerve, infraorbital
nerve, and lacrimal nerve) go to the brain stem, stimulation of
these nerves in only one eye may result in a bilateral tearing
response. Accordingly, the step of placing a device on the cornea
or in the subconjunctiva may involve placing the device in only one
eye. For example, a subject may use a stimulating contact lens in
one eye, and either no contact lens or a non-stimulating corrective
contact lens in the other eye. In some variations, placement of the
stimulating contact may be alternated between the eyes. In other
variations, a subject may wear stimulating contact lenses in both
eyes. Similarly, a stimulator chip may be implanted in only one eye
to achieve a bilateral effect.
[0063] When the device comprises an implant configured to be
implanted in the subconjunctival space, it may be implanted behind
the lower eyelid, as described in more detail herein, where it can
easily be periodically replaced (e.g., every six months) without
any visible scarring. In some variations, an implantable device can
be replaced by removing the old device and placing a new device in
a position next to the previous position on the orbit (e.g., at the
5 o'clock position instead of the 6 o'clock position). This allows
the former incision site to heal and recover. The next replacement
of the implant may be put in yet another position near the old
insertion site but still hidden behind the lower eyelid to avoid
cosmetic impact. In some variations, the implantable device can be
replaced by removing the old device and placing the new device in
the opposite eye. This may reduce accommodation and/or minimize
scarring.
[0064] In some instances, the eye may be imaged using
high-resolution ultrasound, optical coherence tomography (OCT), or
other imaging technique prior to implantation. The images may be
used, for example, to assist in implanting the device (e.g., how
deep to insert the implant based on the thickness of the
conjunctiva or to verify that a patient is suitable for the
procedure by possessing a conjunctiva that is thick enough to hold
such an implanted device with a significant enough safety margin),
selecting an appropriately sized/shaped implant for the patient's
eye anatomy, and/or determining the source power needed to activate
the stimulating chip.
[0065] After one or more contacts or implants is located on or in
the eye, the methods may further comprise activating the stimulator
chip using an external power source, and stimulating the cornea
and/or conjunctiva to activate the reflex pathway and increase
lacrimation and/or tear quality by increasing meibomian secretion
or accessory gland secretion. In variations where the external
power source is handheld, the handheld power source may be moved
toward the eye, to a distance at which the external power source
can deliver the intensity to generate the desired electrical
stimulus. The distance can range from approximately 1 cm to
approximately 1 m. Power sources at greater distances from the eye
may require greater total power to activate the stimulator, due to
light spread. In order to limit the total power output, and thus
the potential for harming the iris, it may be desirable to have the
distance be approximately 5-10 cm. In variations where the external
power source is a mountable, the power source may have been mounted
to a location adjacent to where the subject may look for extended
periods of time, and the eye may be moved toward the external power
source. When the external power source comprises an on/off switch,
the power source may be turned on. If the stimulator chip is
covered by an eyelid when the subject is looking forward, the
eyeball (or, additionally or alternatively, the eyelid) may be
moved to expose the stimulator chip to the power source.
[0066] Activation of the stimulator chip to generate a stimulus,
which may in turn cause tearing or other effects, may be performed
throughout the day on an as-needed basis and/or according to a
pre-determined regimen. In some instances, a user may use one of
the devices described herein to provide a round of stimulation when
the user experiences symptoms of dry eye. A round of stimulation
may have any suitable duration (e.g., between 1 second and 10
minutes). In other instances, the devices may be used to provide
stimulation on a scheduled basis. For example, in some variations
the devices described here may be used to provide a round of
stimulation at least once daily, at least once weekly, or the like.
In some variations, the devices may be used to deliver multiple
rounds of stimulation each day (e.g., at least two treatments
daily, at least four treatments daily, at least six times daily,
between four and eight times daily, etc.) In some variations, the
stimulation may be delivered at certain times of day. In other
variations, the stimulation may be delivered at any time during the
day as desired or determined by the user. When the device is used
to provide stimulation on a scheduled basis, in some variations
each round of stimulation may be the same length (e.g., about 30
seconds, about 1 minute, about 2 minutes, about 3 minutes, about 4
minutes). In other variations, some rounds of stimulation may have
different predetermined lengths. In yet other variations, the user
may choose the length of the round of stimulation.
Methods of Manufacturing
[0067] In some variations, the methods described here comprise
methods of manufacturing a contact lens that is configured to
increase tear production by stimulating the cornea and/or
conjunctiva. The manufacturing method is designed to reproducibly
form a lens body with an embedded stimulator chip, where the
stimulator chip is in a specific orientation and position within
the lens body. Close proximity of the stimulator chip to the eye
surface allows for effective stimulation of the cornea,
conjunctiva, and/or subconjunctiva, while exposure of the
stimulator chip to the eye may result in a foreign body sensation
and irritation. Accordingly, in some variations, the stimulator
chip may be within 5 microns, within 10 microns, or within 10-20
microns of the posterior surface of the lens.
[0068] Lathe Cutting
[0069] The methods of manufacturing a contact lens as described
herein may comprise the step of embedding a stimulator chip in a
lens body by sheet casting or rod casting. The method may further
comprise the step of lathe cutting the casting to a desired
shape.
[0070] When manufacturing the contact lens described here uses
sheet casting, as shown in FIG. 9A, stimulator chips 918 may be set
into a fixture 950. The stimulator chips 918 may be oriented with
the electrodes 928, 930 positioned downwardly in the fixture 950 to
create an electrode layer 952, as shown in FIG. 9B. A mix/pre-mix
biomaterial may be poured into a mold 954 defined by the fixture
950. The biomaterial may be cured, post-cured, and annealed to
create a biomaterial sheet 956, as shown in FIG. 9B. The electrode
layer 952 may be sealed by reversing the biomaterial sheet 956,
adding a thin film 958, and curing, as shown in FIG. 9C. Overall
thickness of the sheet cast may be controlled by the curing time
and temperature and thin-film thickness. FIG. 9D shows button
development by milling, laser cutting, or coring of the sheets.
[0071] When manufacturing a contact lens described here uses rod
casting, as shown in FIG. 10A, a rod mold 1050 may be developed.
Stimulator chips 1018 may be fixated at pre-set levels/positions
within the rod mold 1050. A pre-mix/monomer biomaterial may be
poured into mold 1050. The biomaterial may be cured, post-cured,
and annealed, as shown in FIG. 10B. FIG. 10C shows the steps of
de-molding, and cutting or sawing the rod into buttons. A top view
and side view of a button created from rod casting is shown in FIG.
10D.
[0072] Once the buttons are formed using sheet casting or rod
casting methods, the biomaterial with embedded stimulator chips may
be lathe cut to a meniscus shape. The anterior and posterior lathe
cuts may be achieved by blocking the button on a chuck using vacuum
or wax. The radius may be cut to various shapes and dimensions
including aspheric surfaces, toric surfaces, multifocal,
diffractive, and the like. Typical shapes for contact lenses are
meniscus lenses. FIGS. 11A-11C show the shaping of a lens from
button form to a meniscus lens using lathe cutting. FIG. 11A shows
a side view of a button 1100 with a stimulator chip 1118. FIG. 11B
shows the button of FIG. 11A with an anterior cut defining an
anterior surface with three different radii of curvature R.sub.1,
R.sub.2, and R.sub.3. FIG. 11C further shows a posterior cut
defining an anterior surface with three different radii of
curvature R.sub.4, R.sub.5, and R.sub.6.
[0073] Control over spacing of the stimulator chip and the
posterior surface of the lens may be achieved by appropriately
locating the stimulator chip on the button surface during casting
stages. Thickness may be controlled using a combination of casting
and lathing processes to ensure that the stimulator chip is close
to the posterior surface of the contact lens without being exposed,
as described in more detail herein.
[0074] Cast Molding
[0075] In some variations, the methods of manufacturing a contact
lens may comprise embedding a stimulator chip in a lens body and
shaping the lens body by direct cast molding. Disposable or metal
molds that follow the contour/shape of the lens shown in FIG. 11C
may be directly molded using highly polished surfaces (e.g.,
chrome- or steel-coated metal). As shown in FIG. 12A, a mold 1250
may comprise a first part 1252, a second part 1254, and a port 1256
for receiving a biomaterial. A stimulator chip 1218 may be
positioned within the space 1258 created between first and second
parts 1252, 1254 of mold 1250. A biomaterial, which may be a
monomer mix, for example, may be fed into the space 1258. The
biomaterial may be cured, cast, and de-molded to provide the
intermediate lens 1260 shown in FIG. 12B.
[0076] To coat the second surface after cast molding, spray coating
or thin-film coating may be employed. In some variations, as shown
in FIG. 12C, a second mold 1262 may be used to create a thin layer
to form the second surface. Lens 1260 may be placed in a space
between a first part 1264 and a second part 1266 of mold 1262. A
pre-mix biomaterial may be fed through a port 1268 and into the
space, thereby creating a thin layer 1270 to a height of
approximately 10-20 microns, or another suitable height as
described herein. The biomaterial may be cured and de-molded. FIG.
12D shows a side view of the complete contact lens 1210 comprising
the stimulator chip 1218 formed using cast molding method.
[0077] The final steps of processing may include hydration,
cleaning, packaging, and sterilization or aseptic processing. An
additional step of polishing, by tumble or pad for example, may be
performed to achieve the surface quality desired.
* * * * *