Patent Description:
Contact lenses that provide refractive vision correction are commonplace. Most contact lenses in use today are so-called soft contact lenses. They are relatively thin and made of oxygen permeable hydrogels. Oxygen passes through the contact lens material to the cornea. Sufficient oxygen supply is an important requirement for any contact lens because, due to the lack of blood vessels within the human cornea, the tissue that makes up the cornea receives oxygen through exposure to the air. Without a sufficient flow of oxygen through the contact lens, the cornea would suffer.

Recently, there has been increased interest in contact lenses that perform functions other than vision correction. In many of these applications, a contact lens may carry a payload for performing various functions. For example, a contact lens may contain a payload of one or more electrical components, such as projectors, imaging devices, sensors, gyroscopes, batteries, MEMS (micro-electro-mechanical systems), accelerometers and magnetometers, etc. The contact lens must have a sufficient thickness and structural integrity to accommodate the payload. However, increasing the thickness of a contact lens reduces the amount of oxygen that is transmitted through the material of the contact lens to reach the cornea. Often, the payload itself also is not gas permeable, which further reduces the oxygen flow.

As a result, it can be challenging to provide an oxygenation path from the external environment to the cornea, while still meeting the other requirements of the contact lens.

An example of a scleral contact lens with an oxygenation path is disclosed in <CIT>.

The invention is defined by the claims of the present patent.

Embodiments of the disclosure have other advantages and features which will be more readily apparent from the following detailed description and the appended claims, when taken in conjunction with the examples in the accompanying drawings, in which:.

The figures and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed.

A contact lens may carry a payload for performing various functions. For example, a contact lens may contain a payload of one or more electrical components, such as a projector, an imaging device, one or more sensors, etc. The contact lens must have a sufficient thickness to accommodate the payload. However, increasing the thickness of a contact lens may reduce the amount of oxygen that can be transmitted through the material of the contact lens to reach the cornea.

In order to ensure sufficient corneal oxygenation while maintaining sufficient structural integrity, a scleral contact lens may be constructed in three layers, including an outer covering, a middle structure, and an inner covering. The middle structure may contain a payload(s) and is referred to as the core. The core may comprise a material having mechanical integrity to carry the payload. In some embodiments, the core material has poor oxygen transmissibility.

A portion of the outward-facing (i.e., facing the external environment) surface of the core is covered by the outer covering in areas that are exposed to ambient oxygen. The inner covering covers an inward-facing surface of the core above the user's cornea. When worn by a wearer, the outer covering faces the outside environment, while the inner covering is proximate to the wearer's cornea. The outer covering and inner covering are each a thin layer of gas-permeable material, each shaped to form a respective interstitial cavity (also referred to as "air gaps") between them and the core. The cavities are connected by an air path (e.g., air shafts) that traverses the core. Oxygen from the outside environment passes through the gas-permeable outer covering to reach the outer cavity formed between the outer covering and the core, through the air path to the inner cavity formed between the core and the inner covering, and through the gas-permeable inner covering to reach the cornea of the wearer's eye.

<FIG> shows a user wearing a display mounted in a scleral contact lens, in accordance with some embodiments. In some embodiments, the user may wear a scleral contact lens on one eye. In other embodiments, the user may wear a scleral contact lens over each eye. In cases where the user wears a pair of scleral contact lens, each of the scleral contact lenses may contain different payloads, allowing each scleral contact lens to perform different functions. For example, in some embodiments, each scleral contact lens may comprise a projector configured to project images into a respective eye of the user, but also comprise different sensors or other components to provide different types of functionality.

In some embodiments, due to space for processing components on the scleral contact lens being limited, the scleral contact lens <NUM> is configured to interface with an external device to provide certain functionalities, such as image processing functions, sensor analysis functions, etc. In addition, in some embodiments, the scleral contact lens <NUM> comprises a power coil configured to receive power wirelessly from an external device. In some embodiments, the external device is an accessary device worn by the user, such as a necklace, headband, glasses, or other wearable device. In other embodiments, the external device is an electronic device such as a mobile phone. In some embodiments, the scleral contact lens <NUM> may be powered by one or more batteries within the contact lens, and may interface with an external device for performing certain processing functions. In some embodiments, the external device may be configured to communicate with a remote server (e.g., a cloud server).

<FIG> shows a cross sectional view of the scleral contact lens mounted on the user's eye, in accordance with some embodiments. Scleral contact lenses are designed to be mounted on the sclera of the user's eye such that they do not move around on the wearer's eye when worn. The eye <NUM> includes a cornea <NUM> and a sclera <NUM>. The scleral contact lens <NUM> is supported by the sclera <NUM> and vaults over the cornea <NUM>, typically forming a tear fluid layer <NUM> between the contact lens <NUM> and the cornea. Oxygen permeates through the contact lens <NUM> and tear fluid layer <NUM> to the cornea <NUM>, at a rate depending upon the geometry of the contact lens <NUM> and the oxygen transmissibility and thicknesses of the materials that form the contact lens <NUM> (not shown in this figure).

The contact lens <NUM> contains payload(s). These payloads may not be gas-permeable and also may require the contact lens to have a thickness and structural strength sufficient to accommodate and support the payloads. As a result, the approach used in soft contact lenses for corneal oxygenation typically will not be adequate for contact lens <NUM>. In some embodiments, the payload(s) may include electronics, including electronics that require a power source such as a battery or a coil that is inductively powered. In the example of <FIG>, the payloads include a small projector that projects images onto the wearer's retina (referred to as a femtoprojector <NUM>), and the corresponding electronics <NUM> to operate the femtoprojector (e.g., driver circuitry for the femtoprojector). In some embodiments, both of these are powered by a coil <NUM> around the periphery of the contact lens. In other embodiments, the femtoprojector <NUM> and electronics <NUM> may be powered by a battery or other type of power source located within the contact lens <NUM> (not shown).

The femtoprojector <NUM> may include an LED frontplane with an LED array, an ASIC backplane with electronics that receives the data to drive the LED frontplane, and optics to project light from the LED array onto the retina. The femtoprojector <NUM> preferably fits into a <NUM> by <NUM> by <NUM> volume or even into a <NUM> by <NUM> by <NUM> volume. The contact lens <NUM> must be sufficiently thick and structurally sound to support the femtoprojector <NUM> and electronics <NUM>, while still maintaining adequate oxygen flow to the cornea.

To allow the femtoprojector <NUM> to project images onto the user's retina, the femtoprojector <NUM> may be positioned over the cornea. On the other hand, the electronics <NUM> may be positioned away from the cornea, as shown in <FIG>. For convenience, the contact lens <NUM> is divided into a central zone and a peripheral zone. The central zone may refer to an area of the contact lens that overlaps the cornea <NUM> of the eye <NUM>, while the area of the contact lens outside the cornea is referred to as the peripheral zone. As illustrated in <FIG>, the femtoprojector <NUM> is located within the central zone of the contact lens, while the electronics <NUM> and coil <NUM> are located in the peripheral zone. People have eyes of different sizes and shapes. The central zone may be defined as a portion of the contact lens that is within a certain distance of a center axis of the contact lens. The diameter of the boundary between the cornea and the sclera is typically between <NUM> and <NUM>, so for convenience, the central zone may be defined as the <NUM> diameter center area of the contact lens (i.e., within <NUM> radius of the center axis of the contact lens). Payload components that project light onto the retina typically will be located within the central zone due to the required optical path. Conversely, payload components that do not project light onto the retina or otherwise interact with the retina may be located on the edge of the central zone or outside the central zone so that they do not block light from reaching the retina.

Other examples of powered payloads include sensors, imagers, and eye tracking components such as accelerometers, gyroscopes and magnetometers. Payloads may also include passive devices, such as a coil or antenna for wireless power or data transmission, capacitors for energy storage, and passive optical structures (e.g., absorbing light baffles, beam-splitters, imaging optics). The contact lens <NUM> may also contain multiple femtoprojectors, each of which projects images onto the user's retina. Because the contact lens <NUM> moves with the user's eye <NUM> as the user's eye rotates in its socket, the femtoprojectors mounted in the contact lens <NUM> will also move with the user's eye and project to the same region of the retina. Some femtoprojector(s) may always project images to the fovea, and other femtoprojector(s) may always project images to more peripheral regions which have lower resolutions. As a result, different femtoprojectors may have different resolutions. The images from different femtoprojectors may be overlapping, to form a composite image on the wearer's retina. Contact lens having one or more femtoprojectors may hereafter referred to as "contact lens displays" or "eye mounted displays.

<FIG> is a functional block diagram of an eye-mounted display using a scleral contact lens, in accordance with some embodiments. The display can be divided into a data/control subsystem <NUM> and a power subsystem <NUM>. In some embodiments, the receive path of the data/control subsystem <NUM> includes an antenna <NUM>, receiver circuitry <NUM>, a data pipeline <NUM>, and a femtoprojector <NUM>. Data from an external source (e.g., an external device such as an accessory device) is wirelessly transmitted to the display via the antenna <NUM>. The receiver circuitry <NUM> performs the functions for receiving the data, for example demodulation, noise filtering, and amplification. It also converts the received signals to digital form. The pipeline <NUM> processes the digital signals for the femtoprojector <NUM>. These functions may include decoding, and timing. The processing may also depend on other signals generated internally within the contact lens, for example eye tracking <NUM> or ambient light sensing. The femtoprojector <NUM> then projects the corresponding images onto the wearer's retina. In this example, the femtoprojector <NUM> includes a CMOS ASIC backplane <NUM>, LED frontplane <NUM> and optics <NUM>, as described previously.

The data/control subsystem <NUM> may also include a back channel through transmitter circuitry <NUM> and antenna <NUM>. For example, the contact lens may transmit eye tracking data, control data and/or data about the status of the contact lens.

In some embodiments, power is received wirelessly via a power coil <NUM>. This is coupled to circuitry <NUM> that conditions and distributes the incoming power (e.g., converting from AC to DC if needed). The power subsystem <NUM> may also include energy storage devices, such as batteries <NUM> or capacitors (not shown), in addition to or instead of the power coil <NUM>. For example, in some embodiments, the power coil <NUM> is used to charge the battery <NUM>, which distributes power to the components of the data/control subsystem <NUM>. In some embodiments, the contact lens may comprise the battery <NUM> but no power coil <NUM>, or vice versa.

In addition to the components shown in <FIG>, the overall system may also include components that are outside the contact lens (i.e., off-lens). For example, head tracking and eye tracking functions may be performed partly or entirely off-lens (e.g., sensor within the contact lens may transmit raw sensor data to an external device, which analyzes the received data to calculate a head or eye orientation). The data pipeline may also be performed partially or entirely off-lens. Each of the arrows on the left-hand side of <FIG> also connects to an off-lens component. The power transmitter coil is off-lens, the source of image data and control data for the contact lens display is off-lens, and the receive side of the back channel is off-lens.

There are many ways to implement the different system functions. Some portions of the system may be entirely external to the user, while other portions may be worn by the user in the form of a headpiece or glasses. Components may also be worn on a belt, armband, wrist piece, necklace, or other types of packs. For example, in some embodiments, the contact lens may receive image content to be displayed by the femtoprojector <NUM> from an external device associated with the user via the antenna <NUM>. The external device may further communicate with a server (e.g., a remote server) to generate the image content.

<FIG> is a simplified perspective view of a scleral contacts lens able to accommodate a thick payload, where the contact lens is configured to be mounted on the user's eye, in accordance with some embodiments. In some embodiments, a thick payload may refer to a payload greater than <NUM> in thickness. With respect to the contact lens, terms such as "outer" "over" "top" and "up" refer to the direction away from the wearer's eye, while "inner" "under" "bottom" and "down" refer to the direction towards the wearer's eye. The scleral contact lens <NUM> includes a core <NUM> that carries the payload(s). The core <NUM> has a base surface <NUM> that mounts to the sclera of the eye, an outer surface <NUM> that faces outwards towards the external environment, and an inner surface <NUM> that faces inwards towards the cornea of the eye. The contact lens <NUM> also includes an outer covering <NUM> that covers at least a portion of the outer surface <NUM> of the core, and an inner covering <NUM> that covers at least a portion of the inner surface <NUM> of the core. Each covering <NUM>, <NUM> forms a corresponding air cavity <NUM>, <NUM> between the covering and the core <NUM>. An air path <NUM> through the core <NUM> connects the two cavities <NUM>, <NUM>. As used herein, the cavities <NUM> and <NUM> may also be referred to as an outer air gap <NUM> and an inner air gap <NUM>, respectively.

Together, the outer covering <NUM>, core <NUM>, and inner covering <NUM> form a three-layer contact lens <NUM>. The outer covering <NUM>, core <NUM>, and inner covering <NUM> are shaped such that when the contact lens is assembled, an outer cavity <NUM> is formed between the outer covering <NUM> and the core <NUM>, and an inner cavity <NUM> is formed between the core <NUM> and the inner covering <NUM>. Because the outer and inner cavities <NUM> and <NUM> are each entirely enclosed by their respective structures, the cavities are not directly exposed to the external environment, preventing any debris or other contaminants from the outside air or from the tear layer from potentially reaching either cavity.

The outer covering <NUM> is exposed to air or separated from air by a thin tear layer that forms over the covering. As such, oxygen diffuses from the surrounding air through the gas permeable material of the outer covering <NUM> (and thin tear layer) to reach the outer cavity <NUM>. The oxygen in the outer cavity <NUM> diffuses through an air path <NUM> to traverse through the thickness of the core <NUM> to reach the inner cavity <NUM>. From the inner cavity <NUM>, oxygen diffuses through the gas permeable material of the inner covering <NUM> to reach the tear fluid layer and underlying cornea of the wearer. Because the inner cavity <NUM> may cover all or most of the wearer's cornea, oxygen may be distributed evenly across the wearer's cornea through the inner covering <NUM>. In some embodiments, one or more surfaces the outer covering and/or the inner covering may be covered with a coating of hydrophilic material, to make the contact lens more comfortable to wear (e.g., by improving lubricity of the contact lens) and/or to preserve gas permeability of the coverings. In some embodiments, portions of the core not covered by the outer and inner coverings (such as the exposed portions of the outer surface of the core) are covered with a coating of hydrophilic material, to increase wearer comfort by improving lubricity.

Oxygen diffusion through the air (such as in the cavities <NUM>, <NUM> and air path <NUM>) is roughly <NUM>,<NUM> times more rapid than diffusion through permeable solids such as rigid gas permeable ("RGP") plastic. As a result, the oxygen transmissibility of the contact lens <NUM> is defined primarily by the thicknesses and materials of the two coverings <NUM>, <NUM>, and not by the thickness of the cavities <NUM>, <NUM>, air path <NUM>, or the core <NUM>. The oxygen transmissibility "Dk/t" of the entire contact lens <NUM> may be approximated based upon the Dk/t of the areas of the outer covering <NUM> and inner covering <NUM> overlapping the outer cavity <NUM> and inner cavity <NUM>, respectively, and not on the thickness or material of the core <NUM>. The thickness and material of the core <NUM> may be selected to accommodate a desired payload and provide sufficient structural strength to support the payload. Here, Dk is oxygen permeability, where D is a diffusion constant measured in <MAT>, and k is a concentration of O<NUM> per unit of O<NUM> partial pressure and is measured in <MAT>. The t is thickness of the material. Dk/t is often quoted in units of <NUM>-<NUM> <MAT>. Some sources recommend an oxygen transmissibility of Dk/t = <NUM> as the minimum for daily wear contact lenses, and an oxygen transmissibility of Dk/t = <NUM> as the minimum recommended for extended wear lenses in contact with the cornea.

In <FIG>, the inner covering <NUM> and inner cavity <NUM> are large enough to cover substantially all of the cornea. In this way, oxygen can diffuse from the cavity <NUM> through the inner covering <NUM> directly to all parts of the cornea. Lateral diffusion through the inner covering <NUM> or tear layer is generally not required. To accommodate typical corneas, the inner covering <NUM> and inner cavity <NUM> each have a circular edge of at least approximately <NUM>-<NUM> in diameter.

For the outer covering <NUM> and outer cavity <NUM>, the location is less important than the overall surface area exposed to ambient oxygen. In some designs, the outer structure <NUM>, <NUM> has a same surface area as the inner structure <NUM>, <NUM>. That is, in <FIG>, the overlap area between the outer covering <NUM> and outer cavity <NUM> is at least equal to the overlap area between the inner covering <NUM> and inner cavity <NUM>.

The air path <NUM> in <FIG> is a single air shaft through a solid section of the core <NUM>, for example a <NUM> diameter air shaft. Because oxygen diffusion in air is high, the specific shape and location of the air path <NUM> is secondary in importance, so long as it connects the two cavities <NUM>, <NUM>. For example, the air path may be implemented as two or more air shafts instead of one air shaft. It may also be located in a periphery of the contact lens, for example outside a <NUM> diameter central zone, so that it does not interfere with light entering the eye.

The coverings <NUM>,<NUM> are each relatively thin in comparison to the core <NUM> and are made of materials that are permeable to oxygen such as rigid gas permeable ("RGP") plastic. On the other hand, the core <NUM> is sufficiently thick to accommodate the payloads, such as femtoprojectors and electronic components. The core <NUM> may also be made from an oxygen permeable material such as RGP, or from an oxygen impermeable material such as poly(methyl methacrylate) ("PMMA"). The approach described above may also be used when the core <NUM> does not contain a payload, but is so thick that it would have insufficient oxygen transmission. In some embodiments, the outer covering <NUM>, core <NUM>, and inner covering <NUM> are bonded to each other via an adhesive. Suitable adhesives may include glues such as medical grade optical cement. Example glues that may be appropriate for this application include UV-curable optical adhesives from Henkel Loctite.

In some embodiments, such as in the design shown in <FIG>, the core <NUM> makes contact with the sclera through the base surface <NUM>, while the inner covering <NUM> does not contact the sclera. This provides additional space in the core to accommodate payloads, compared to designs in which the core does not extend all the way to the sclera. This approach may also provide more payload space located close to the perimeter of the contact lens. For example, a coil may be located closer to the perimeter, resulting in a larger area coil and more efficient power transfer. The core <NUM> material is also a good structural material to support the payloads. In some embodiments, the both core <NUM> and inner covering <NUM> may contact the sclera.

In some embodiments, the outer covering <NUM> has an annular shape and does not cover a center area of the contact lens. For example, the outer covering <NUM> may have a center hole have a diameter of at least <NUM>, at least <NUM>, or at least <NUM>. Because the outer covering <NUM> does not extend to the center of the core <NUM>, the outer covering <NUM> does not contribute to the total thickness at the center of the contact lens <NUM>. As a result, the contact lens <NUM> has a reduced thickness in comparison to a contact lens having an outer covering that also covers the center of the core (e.g., a dome-shaped outer covering). In addition, if the center hole of the outer covering <NUM> is large enough (e.g., <NUM> diameter or larger), a number of boundaries between different materials that light may need to pass through en route to the wearer's eye in comparison to if the outer covering was formed to cover the central zone is reduced. As such, by configuring the shape of the outer covering such that it does not interfere with light passing through the contact lens to reach the wearer's eye, potential optical reflection or scattering that may occur at the boundaries between the outer covering <NUM>, the outer cavity <NUM>, and the core <NUM> is eliminated. Furthermore, an annular outer covering <NUM> may be more durable and more easily supported by the core <NUM> in comparison to one that must be supported over the entire center area of the contact lens. Thus, the outer covering <NUM> can be made thinner while still maintaining structural integrity, which increases the oxygen transmission through the outer covering.

In addition, in some embodiments, the coverings <NUM>, <NUM> are flush with the core <NUM>. The outer surface <NUM> of the core has a recess for the outer covering <NUM>, so that the outer covering and the core's adjoining outer surface <NUM> form a smooth surface. Because the eyelid blinks over the contact lens, a smooth outer surface is more comfortable, as well as providing an overall thinner contact lens as described above. The inner surface <NUM> of the core also has a recess for the inner covering <NUM>, also resulting in a smooth surface between the two.

<FIG> are a more detailed perspective view, cross-sectional view and exploded view of the scleral contact lens shown in <FIG>. As shown in <FIG>, the outer covering <NUM>, core <NUM>, and inner covering <NUM> are overlaid on top of each other to form the contact lens <NUM>, and may be aligned and secured using one or more registration features. These registration features <NUM> and <NUM> are marked on the left side of <FIG>. The structures may also contain support features such as ridges or protrusions, or spacers such as plastic micro balls, cylindrical or rectangular posts, etc., to prevent the air gaps from collapsing and to maintain the overall structural integrity of the contact lens (not shown).

In addition to the structures shown in <FIG> for oxygen transmission, <FIG> also shows the femtoprojector <NUM> and electronics <NUM> (and interconnect between them) and coil <NUM> from <FIG>. The core <NUM> includes features to accommodate these payloads. For example, the core <NUM> has a through-hole <NUM> within the central zone of the core to accommodate the femtoprojector <NUM>. The femtoprojector <NUM> is placed within the through-hole <NUM> and secured using an encapsulating material, which functions both to fix the position of the femtoprojector and to protect the femtoprojector from the outside environment.

As another example, the core <NUM> also includes a groove <NUM> formed around the circumference of the core <NUM>. The power coil <NUM> is wound inside this groove <NUM>. Note that in the embodiment illustrated in <FIG>, the groove <NUM> is not separated from the outer air gap <NUM>, which may allow components to be located close to the perimeter of the contact lens. In some cases, the component (e.g., coils <NUM>) may be encapsulated in an adhesive or other material so that the components are not exposed to the air within the outer air gap <NUM>. Other features may be used to accommodate other payloads, such as the electronics <NUM> or interconnects.

In <FIG>, the air path is a single air shaft <NUM>. It is formed within the core <NUM> and traverses the thickness of the core <NUM> to connect the outer air gap <NUM> to the inner air gap <NUM>. The air shaft <NUM> is formed in the peripheral zone of the core <NUM>. It may be oriented to be substantially perpendicular to the outer and inner surfaces of the core <NUM>, and connects laterally overlapping portions of the outer air gap <NUM> and inner air gap <NUM>. In some embodiments, multiple air shafts <NUM> may traverse the core <NUM> to connect the outer and inner air gaps <NUM> and <NUM>.

In some embodiments, the components of the contact lens (the outer covering <NUM>, core <NUM>, and inner covering <NUM>) are manufactured separately and assembled together at a later time. For example, the outer covering <NUM>, core <NUM>, and inner covering <NUM> may each be a prefabricated component. Different variations of each component may be fabricated to create different possible combinations. In some embodiments, the inner covering <NUM> may be customized to provide a desired amount of refractive correction (e.g., customized for a specific wearer, or one or a plurality of predetermined refractive correction amounts, etc.). For example, the thickness and inner surface of the inner covering <NUM> may be adjusted to achieve different amounts of refractive correction. On the other hand, the outer covering <NUM> and the core <NUM> may be manufactured as standard components. The outer surface of the inner covering <NUM> may have a predetermined common shape, allowing for the outer covering <NUM> and core <NUM> to be placed on different inner coverings <NUM> having different amounts of refractive correction. In other embodiments, different variations of the outer covering <NUM> and core <NUM> may be manufactured and assembled with the remaining components. In some embodiments, the shapes of the components may be modified by precision machining on a diamond lathe.

The structure and material of the coverings influences the amount of oxygen that is able to flow from the outside environment to the user's cornea. The flow of oxygen may be increased by decreasing the thickness of the coverings. However, thinner coverings do not have the structural integrity to span long distances without support. In some embodiments, to facilitate oxygen flow, at least one of the inner covering, the outer covering, and the core is formed to have a patterned structure of varying thicknesses, such as a pattern of recesses interspersed with supports. The patterned structure may be formed on an inner surface of the outer covering, on an outer surface of the inner covering, on a portion of the outer surface of the core facing the outer covering, or on a portion of the inner surface of the core facing the inner covering. The core and covering contact each other at the supports, and the recesses form the cavity for oxygen flow. Because each recess spans only a short distance between supports, the covering may be made thinner, thus increasing oxygen transmission.

For ease of discussion, <FIG> and <FIG> below show the patterned structure as being formed on the inner surface of the outer covering. In such an arrangement, the core and outer covering contact each other at the supports of the patterned structure, while the recesses of the patterned structure form the cavity between the core and outer covering, allowing for oxygen flow from the external environment to pass through the outer covering to the cavity. Because each recess spans only a short distance between supports, the outer covering may be made thinner without compromising structural integrity.

According to the present invention, the patterned structure comprises a pattern of blind holes. <FIG> shows a side and a top-down view of a patterned structure formed on the outer covering of a scleral contact lens, in accordance with some embodiments. As illustrated in <FIG>, a pattern of blind holes <NUM> are formed on an inner surface of the outer covering <NUM> of the scleral contact lens. In this example, the maximum thickness <NUM> of the outer covering <NUM> is <NUM> (microns). Each of the blind holes <NUM> creates a recess within the outer covering <NUM> where the outer covering has a reduced thickness <NUM> (<NUM> in this example). In some embodiments, the reduced thickness <NUM> of the outer covering corresponding to the recesses defined by the blind holes <NUM> is significantly smaller than the maximum thickness <NUM> of the outer covering (e.g., ~<NUM>% of the maximum thickness). For example, in some embodiments, the outer covering (prior to forming of the patterned structure) may have a thickness of approximately <NUM>, while the thickness of the outer covering within the recesses may be approximately <NUM>. It is understood that any specific dimensions discussed herein are used solely for purpose of example, and that patterned structures and contact lens components may have dimensions other than those discussed herein.

The patterned structure is formed such that when the outer covering <NUM> is placed over the core <NUM>, portions of the outer covering <NUM> between each of the blind holes <NUM> will contact the outer surface of the core <NUM>. As such, each portion of reduced thickness of the outer covering <NUM> (defined by the blind holes <NUM>) spans only a short distance over the core <NUM>. This allows for the thickness of outer covering <NUM> within the recesses to be reduced, while still maintaining structural integrity.

According to the invention, one or more pillars <NUM> are formed on the portions of the outer covering <NUM> between the blind holes <NUM>. When the outer covering <NUM> is placed over the core <NUM>, the pillars <NUM> function to support the outer covering <NUM> on the core <NUM>, as well as space a portion of outer covering <NUM> between the blind holes <NUM> away from the core <NUM>. This space between the pillars <NUM> defines the air cavity <NUM> (also referred to as channels or passages <NUM>) connecting adjacent blind holes <NUM> and allowing air to flow between them. The blind holes <NUM> and their connecting channels <NUM> thus collectively form a single cavity between the outer covering <NUM> and the core <NUM>, allowing oxygen passing through the outer covering <NUM> at the location of any of the blind holes <NUM> to reach an air passage(s) within the core (e.g., air path <NUM>) and the inner cavity.

In some embodiments, the blind holes <NUM> are formed in a hexagonal pattern, where each of the blind holes <NUM> is surrounded by six adjacent blind holes. In addition, as illustrated in <FIG>, each pillar <NUM> may be located between three adjacent blind holes <NUM>. In other embodiments, the blind holes <NUM> may be formed in a rectangular pattern or other type of pattern. In some embodiments, the blind hole pattern of the patterned structure is configured such that a distance between pillars <NUM> in the patterned structure does not exceed <NUM>.

According to the invention, the blind hole pattern illustrated in <FIG> is formed using a plurality of overlaid blind hole patterns, e.g., a first blind hole pattern comprising blind holes of a first radius and a first depth, and a second blind hole pattern comprising blind holes of a second radius and a second depth. In some embodiments, the first and second blind hole patterns are aligned, such that the blind holes of the first and second blind hole patterns share central axes. As such, the spacing of the blind holes of the first blind hole pattern is the same as the spacing of the blind holes of the second blind hole pattern.

Examples of the use of first and second overlaid blind hole patterns to create the overall pattern are discussed in relation to <FIG> and <FIG> below. <FIG> shows views of a first step in forming the patterned structure of <FIG>. In this first step, large overlapping blind holes <NUM> of shallow depth are cut into the outer covering, thus creating the pillars <NUM>. The depth corresponds to a desired height of the pillars <NUM>. Because oxygen diffusion through the air (e.g., within the channels <NUM> formed between the pillars <NUM>) is roughly <NUM>,<NUM> times more rapid than diffusion through permeable solids (such as that used to form the outer covering <NUM>), the height of each pillar <NUM> (and the height of the resulting channels <NUM> formed between them) may be small compared to the total thickness of the outer covering <NUM> (e.g., between <NUM>-<NUM>% of the thickness of the outer covering). This allows for the pillars <NUM> to more stably support the outer covering <NUM> on the core <NUM>, while the channels <NUM> will still provide sufficient air flow between the blind holes <NUM>.

The radius of these blind holes is selected to be greater than the spacing between the blind holes, such that the blind holes <NUM> will partially overlap when formed on the outer covering <NUM>. However, the radius is selected such that material is left between adjacent blind holes to form the pillars <NUM>. For example, in a hexagonal blind hole pattern, such as that illustrated in <FIG>, each pillar <NUM> is defined by the material left between three adjacent blind holes <NUM>. Consequently, each blind hole <NUM> forms six pillars corresponding to the material left between it and its six adjacent blind holes. In this example, the blind holes cover a <NUM> wide swath of the outer covering.

<FIG> shows views of a second step in forming the patterned structure of <FIG>. Here, a second blind hole <NUM> pattern is formed on the outer covering <NUM> after the formation of the first blind hole pattern of <FIG>. While the first blind hole pattern defines the pillars <NUM>, the second blind hole pattern defines the recesses of the outer covering <NUM>. In some embodiments, each of the blind holes of the second blind hole pattern is aligned with a central axis of a corresponding blind hole <NUM> of the first blind hole pattern (e.g., such that the blindhole <NUM> is centered between a set of pillars <NUM> formed by the first blind hole pattern). The depth of these blind holes <NUM> is selected based upon desired reduced thickness <NUM> of the outer covering within the recessed regions of the patterned structure.

Consequently, after both the first and second blind hole patterns have been formed on the outer covering <NUM>, the surface of the outer covering <NUM> will comprise a plurality of recesses (e.g., defined by the blind holes <NUM> of the second blind hole patterns) where the thickness of the outer covering is greatly reduced, positioned between supports having pillars <NUM> where the outer covering <NUM> is supported by the core <NUM>. Because the rate at which air (including oxygen) is able to pass through the outer covering is inversely proportional to the thickness of the outer covering, oxygen transmission through the outer covering <NUM> at the recesses is greatly increased due to the reduced thickness <NUM> of the outer covering. Oxygen may pass between different blind holes <NUM> via the channels <NUM> formed by spaces between the pillars <NUM>, connecting the blind holes <NUM> of the patterned structure to collectively form a single cavity between the outer covering and core of the contact lens. Oxygen can thus pass through the gas permeable material of the outer covering from the external environment to the recesses defined by the blind holes, and flow between the blind holes to reach an air passage through the core (e.g., the air path <NUM> illustrated in <FIG>) to the inner cavity, where it may then pass through the inner covering to oxygenate the user's cornea.

Although <FIG> and <FIG> illustrate the second blind hole pattern formed after the first blind hole pattern, it is understood that in other embodiments, the first and second blind hole patterns may be formed in a different order.

In addition, although <FIG> illustrate the blind holes of the patterned structure as cylindrical blind holes, it is understood that in some embodiments, the patterned structure may comprise a blind hole pattern in which the blind holes are of a different shape. For example, in some embodiments, the patterned structure comprises a blind hole pattern in which each blind hole is shaped as a frustum, in which a size of the blind hole decreases with depth within the outer covering, i.e., from a first, larger size at the surface of the outer covering on which the blind hole is formed, to a second, smaller size at the maximum depth of the blind hole. In some embodiments, the first and second sizes are selected such that the blind holes will partially overlap up to a certain depth. Material left in non-overlapping regions between adjacent blind holes function as pillars to support the outer covering on the core, while gaps formed by areas of overlap between adjacent blind holes form passages allowing for air flow between the blind holes of the pattern.

Because the patterned structure allows for portions of the outer covering to be greatly reduced in thickness (e.g., ~<NUM>% compared to an original thickness of the outer covering), an overall surface area of the outer covering required to achieve a desired level of oxygen transmission may be reduced, due to oxygen transmissibility being directly proportional to surface area and inversely proportional to thickness of the outer covering.

<FIG> shows a perspective view of an outer covering of a scleral contact lens having a substantially uniform thickness, in accordance with some embodiments. The outer covering <NUM>, when mounted on the core of a contact lens, may contact the core only at the edges of the outer covering, and define an outer cavity between an inner surface thereof and an outer surface of the core having a substantially uniform thickness. To maintain a desired level of structural integrity, the outer covering may need to have at least a minimum thickness. In addition, to achieve a desired level of oxygen transmission, the outer covering <NUM> may need to have at least a particular surface area for a given thickness. For example, in some embodiments, the outer covering may have a thickness of <NUM> and cover a surface area of <NUM><NUM> on the core to achieve a desired oxygenation level.

<FIG> shows a perspective view of an outer covering of a scleral contact lens having a patterned structure formed thereon, in accordance with some embodiments. The patterned structure <NUM> formed on the outer covering <NUM> may comprise the overlaid blind hole pattern such as that illustrated in <FIG> (e.g., first and second overlaid blind hole patterns forming a plurality of blind holes and pillars between adjacent blind holes). The patterned structure <NUM> of the outer covering <NUM> creates intermittent points of support (e.g., at the pillars <NUM> illustrated in <FIG>) between the outer covering <NUM> and the core when outer covering <NUM> is assembled on the core. Because the recessed regions of patterned structure <NUM> formed in the outer covering <NUM> have reduced thickness, the amount of oxygen transmission of the outer covering <NUM> for a given surface area may be increased. As an example, if the recesses of the patterned structure cover <NUM>% of the outer covering and are <NUM>% thinner than the thickness of the outer covering <NUM> of <FIG>, then an amount of oxygen transmission for a given surface area may be increased by at least <MAT> <NUM>%. As such, a total surface area of the core that is covered by the outer covering may be reduced. For example, the outer covering <NUM> illustrated in <FIG> (having a patterned structure <NUM> formed thereon) may have a reduced surface area in comparison to the outer covering <NUM> illustrated in <FIG> (having substantially uniform thickness), but may still be able to provide a similar amount of oxygen transmission to the outer cavity of the contact lens. In some embodiments, the outer covering <NUM> has an annular shape with a width of <NUM> or less. If the patterned structure increases the oxygen transmission by <NUM>% (i.e., <NUM>. 5x the oxygen transmission in <FIG>), then the surface area can be <NUM>% of the surface area in <FIG> and still maintain the same oxygen transmission. In some embodiments, the patterned structure is configured such that the recesses of the patterned structure occupy at least a threshold percentage (e.g., ><NUM>%) of an overall area of the patterned structure, to ensure that the benefit to oxygen transmissibility from having a reduced thickness of the outer covering at the recesses offsets the reduction in transmissible surface area due to contact between the inner covering and core at the supports. In some embodiments, the outer covering may be configured to have, within the area of the patterned structure, an average thickness of less than <NUM>, and cover an area on the contact lens of not more than <NUM><NUM>. In some embodiments, the patterned structure is configured to cover at least a threshold amount of the outer covering (e.g., at least <NUM>/<NUM> of an overall area of the outer covering). In some embodiments, an overall area of the annular outer covering on the core may be not more than <NUM><NUM>. Reducing a surface area of the core covered by the outer covering may allow for additional flexibility regarding placement of various components and payloads on the core (e.g., outer covering, payload components such as electronic components, power coils, etc.).

While the above discussion refers primarily to embodiments where the patterned structure comprises a pattern of blind holes, it is understood that the patterned structure may comprise any type of structure that defines a plurality of recesses interspersed between a plurality of supports. For example, in some embodiments, the patterned structure may comprise a plurality of grooves formed on the inner surface of the outer covering. Regions of the outer covering between the formed grooves define ridges that support the outer covering when placed on the core, while the grooves define recesses where the outer covering is of reduced thickness, facilitating oxygen transmission from the outside environment into the grooves. In some embodiments, the plurality of grooves are connected to each other by one or more passages, allowing for air flow between the grooves. For example, in embodiments where the outer covering is annular in form (e.g., as illustrated in <FIG> and <FIG>), the patterned structure may comprise a plurality of concentric circumferential grooves formed on the outer covering, with one or more additional grooves oriented orthogonally to the circumferential grooves to form passages connecting the circumferential grooves.

In some embodiments, the patterned structure is formed on an outer surface of the core instead of an inner surface of the outer covering. For example, the patterned structure may comprise a plurality of concentric circumferential grooves formed on an outer surface of the core, whereas the outer covering may be of substantially uniform thickness. When mounted on the core, the ridges between pairs of adjacent grooves on the core directly contact an inner surface of the outer covering, functioning as supports for the outer covering, while the space between the inner surface of the outer covering and the grooves with the core form the outer cavity. In some embodiments, the outer covering is formed to be of substantially uniform thickness. However, due to being periodically supported by the patterned structure formed on core, the thickness of the outer covering may be reduced compared to an outer covering that is supported only at its edges.

In some embodiments, forming the patterned structure on the outer surface of the core instead of on an inner surface of the outer covering may improve oxygen transmissibility. Because the outer covering can be formed to be of a reduced uniform thickness, as the supports which would correspond to areas of increased thickness of the outer covering are formed on the core instead of on the outer covering, the impact of the supports on oxygen transmissibility is reduced. In addition, in some embodiments, the supports of the patterned structure formed on core may be rounded, pointed, or otherwise shaped to reduce a contact area with the outer covering, increasing an amount of surface area of the outer covering that contributes to oxygen transmission. In some embodiments, the outer covering over the patterned structure formed on the core may have an average thickness of not more than <NUM>.

Due to the outer covering contacting the core at the supports of the patterned structure when the outer covering is mounted to the core, the portions of the outer covering having reduced thickness (e.g., recesses) will only span a short distance (e.g., corresponding to a distance between supports). However, prior to the outer covering being assembled on the core, these portions of reduced thickness may cause the outer covering to be difficult to handle, due to lack of support from the core leading to potential folding or breakage of the outer covering.

In some embodiments, instead of forming the core and outer covering to their final desired thicknesses, the outer covering and/or the core are initially formed as an outer covering component and/or core component having a larger thickness, which is then cut down to the desired thickness after assembled together. This may help to ensure that the outer covering is thick enough to handle prior to being mounted on (and thus receiving support from) the core.

<FIG> shows an exploded view of a manufactured core component and outer covering component for a scleral contact lens prior to assembly, in accordance with some embodiments. The outer covering component <NUM> is formed from an oxygen permeable material, and has a thickness that facilitates handling of the outer covering component <NUM>. In addition, the core component <NUM> may also be formed to be thicker than its final desired form. For example, in some embodiments, the core component <NUM> may include one or more alignment features or edges <NUM> that serve to align the outer covering component <NUM> when placed over the core component <NUM>, to ensure that the outer covering component <NUM> is positioned correctly relative to the core component <NUM>. The core component <NUM> may further comprise one or more features to facilitate handling of the core component <NUM>.

A patterned structure comprising a plurality of recesses interspersed between a plurality of supports is formed on either the outer covering component <NUM> or the core component <NUM>. For example, as illustrated in <FIG>, the patterned structure may correspond to a plurality of circumferential grooves <NUM> formed on a portion of the core component <NUM>. In addition, an additional groove <NUM> may be formed as part of the patterned structure to function as a passage between the grooves of the circumferential grooves <NUM>.

<FIG> shows side and perspective views of the core component and outer covering component of <FIG> assembled together. As illustrated in <FIG>, the outer covering component <NUM> is placed over the core component <NUM>. The outer covering component <NUM> may be aligned to the core component <NUM> using one or more registration features <NUM>. When the outer covering component <NUM> is placed over the core component <NUM>, an inner surface of the outer covering component <NUM> and an outer surface of the core component directly contact at the supports of the patterned structure (not shown), e.g., ridges of the patterned structure formed between the circumferential grooves <NUM>. In some embodiments, the outer covering component <NUM> and core component <NUM> are fixed to each other using one or more glue layers (not shown).

<FIG> shows side and perspective views of the assembled core component and outer covering component of <FIG> cut down to form the scleral contact lens. After the outer covering component <NUM> has been mounted on the core component <NUM>, an outer surface of the outer covering component <NUM> and the core component <NUM> are shaped to their desired form. In some embodiments, excess material of the outer covering component <NUM> and core component <NUM> is cut away using a lathe, to form the core <NUM> and outer covering <NUM> of the contact lens. The core <NUM> and outer covering <NUM> are shaped such that the outer surface of the outer covering aligns with an outer surface of the core, creating a smooth outer surface for the contact lens. In addition, because the outer covering <NUM> is supported by the core <NUM> (e.g., via supports of the patterned structure), the outer covering <NUM> can be shaped to a reduced thickness to facilitate oxygen transmission from the local environment to the outer cavity formed by the recesses of the patterned structure between the outer covering and the core.

<FIG> shows a side cross-section view of a core component and outer covering component assembled together, where a patterned structure is formed on the core component, in accordance with some embodiments. <FIG> shows a zoomed out cross-section of the core component and outer covering component, while <FIG> shows a close-up view of the interface between the core component and outer covering component zoomed in at area B shown in <FIG>. The core component <NUM> and outer covering component <NUM> illustrated in <FIG> may correspond to the core component <NUM> and outer covering component <NUM> illustrated in <FIG> and <FIG>. As illustrated in <FIG>, the outer covering component <NUM> is placed against the core component <NUM> such that an inner surface of the outer covering component <NUM> directly contacts the supports of a patterned structured <NUM> formed on a portion of an outer surface of the core component <NUM>. In other embodiments (not shown), the patterned structure is formed on the outer covering component <NUM>, which is aligned such that the supports of the patterned structure contact the outer surface of the core component <NUM>.

The outer covering component and core component may contain extra material relative to their final desired forms, to facilitate handling and/or alignment during assembly. For example, the outer covering component <NUM> may be formed from a thick material, allowing for it be more easily handled and with less risk of deformation or breakage during assembly. In addition, the core component <NUM> may comprise alignment features <NUM> that facilitate alignment between the outer covering component <NUM> and the core component <NUM>.

In some embodiments, the outer covering component <NUM> and the core component <NUM> are fixed to each other via a glue layer <NUM> deposited at an edge between the outer covering component <NUM> and the core component <NUM>. In some embodiments, the glue layer <NUM> may fill a space between the outer covering component <NUM> and the core component <NUM> extending to an outer support of the patterned structure <NUM>. However, the outer support of the patterned structure, due to creating direct contact between the core component <NUM> and outer covering component <NUM>, prevents the glue <NUM> from reaching the recesses within the patterned structure <NUM>. The glue <NUM> may function to seal the recesses of the patterned structure <NUM> away from the outside environment. Consequently, air can only reach the cavity formed between the outer covering component <NUM> and core component <NUM> defined by the recesses through the gas permeable material of the outer covering component <NUM>, thus preventing outside debris and contaminants from entering the outer cavity.

<FIG> shows a side cross-section view of the core component and outer covering component of <FIG> assembled together and cut down to form the scleral contact lens. <FIG> shows a zoomed out cross-section, while <FIG> shows a close-up view of the interface between the core component and outer covering component zoomed in at area C shown in <FIG>. As illustrated in <FIG>, the assembled outer covering component and core component are cut down to form a core <NUM> and outer covering <NUM> having a smooth outer surface <NUM>. The outer covering <NUM> is shaped to a thickness that allows for a desired amount of oxygen transmission through the outer covering to reach the outer cavity of the contact lens. Because the patterned structure <NUM> is formed on the core <NUM> in the embodiment illustrated in <FIG>, the outer covering <NUM> may be shaped to be of substantially uniform thickness. The outer covering <NUM> is periodically supported by the supports of the patterned structure <NUM>, allowing for the thickness of the outer covering <NUM> to be reduced relative to if the outer covering did not contact the core between the glue layers <NUM>. For example, in some embodiments, the supports of the patterned structure may be spaced such that the outer covering over the area of the patterned structure does not span a distance of more than <NUM>. As such, even though the contact points between the outer covering <NUM> and the supports of the patterned structure formed on the core <NUM> may potentially decrease an area of the outer covering <NUM> through which oxygen can be transmitted, the reduction in thickness that is possible for the outer covering <NUM> may allow for the overall oxygen transmissibility of the outer covering to increase. In some embodiments, the supports of the patterned structure may be rounded or pointed, to reduce an area of the supports in direct contact with the outer covering.

<FIG> is a flowchart of a process for forming a scleral contact lens, in accordance with some embodiments. At <NUM>, a core component is formed. The core component may correspond to the core component <NUM> illustrated in <FIG> or the core component <NUM> illustrated in <FIG> and <FIG>. The core component may be formed to be thicker than the final desired core of the contact lens, and comprise one or more registration features for aligning an outer covering, inner covering, one or more payload components, etc. In some embodiments, the core component is formed from a non-gas permeable material. For example, the material of the core component may be selected to provide structural strength to the contact lens. At least a portion of an outer surface of the core component is shaped to receive a surface of an outer covering component.

At <NUM>, an outer covering component is formed from an oxygen permeable material. The outer covering component comprises at least an inner surface shaped to be mounted on the core component. In some embodiments, the outer covering component is formed thicker in comparison to the final desired outer covering, to facilitate handling and assembly.

At <NUM>, a patterned structure is formed on the core component or the outer covering component. The patterned structure comprises a plurality of recesses interspersed between a plurality of supports. For example, in some embodiments, the patterned structure may comprise one or more blind hole patterns formed on an inner surface of the outer covering component, wherein the blind holes correspond to the recesses and portions of the outer covering component between the blind holes comprise the supports. In some embodiments, portions of the outer covering component between the blind holes may be formed into one or more pillars to function as supports. In some embodiments, the patterned structure may comprise a plurality of circumferential grooves formed on an inner surface of the outer covering component or a portion of the outer surface of the core component, wherein the grooves correspond to recesses and ridges formed between pairs of adjacent grooves correspond to supports.

At <NUM>, the outer covering component is attached to the core component. The outer covering component may be mounted to the core component such that the outer covering component and core component directly contact each other at the supports of the patterned structure. In some embodiments, the outer covering component is attached to the core component via a glue layer formed at the edge of the outer covering component. For example, the glue layer may be formed within a space between the outer covering component and the core component extending to an outer support of the patterned structure, which prevents the glue from entering the recesses of the patterned structure. In some embodiments, an inner surface of the outer covering component is covered with a coating of hydrophilic material prior to the outer covering component being attached to the core component, to improve lubricity of the contact lens and/or to preserve gas permeability of the outer covering component.

At <NUM>, the outer surface of the core component and outer covering component may be shaped to a final desired thickness of the contact lens. In some embodiments, the core component and outer covering component are cut down or lathed to form the final core and outer covering of the contact lens. In some embodiments, once the core component and outer covering component are shaped to the desired form and thickness, a coating of hydrophilic material may be applied to the outer surface of the outer covering.

While the above description primarily discusses a patterned structure associated with the interface between the outer covering and the core, similar techniques may be used to form a patterned structure associated with the interface between the inner covering and the core (e.g., a patterned structured formed on a portion of an inner surface of the core, or an outer surface of the inner covering). This may allow the inner covering to be formed with reduced thicknesses in areas corresponding to the recesses of the patterned structure, which are supported by the supports of the patterned structure.

In some embodiments, because the patterned structure can potentially affect passage of light through the contact lens, the patterned structure is only formed on portions of the contact lens that are outside the central zone of the contact lens. In some embodiments, the outer covering may be disposed entirely outside the central zone of the contact lens. As such, the patterned structured may be formed on the inner surface of the outer covering or on portions of the outer surface of the core to where the outer covering is to be mounted, without substantially affecting passage of light to the user's eye. On the other hand, in embodiments where the inner covering is positioned to cover all or most of the wearer's cornea (e.g., to facilitate even distribution of oxygen across the wearer's cornea through the inner covering), the patterned structure may be formed only on portions of the inner covering or core outside the central zone of the contact lens. It may not be necessary to form a patterned structure associated with the inner covering if a desired level of oxygenation can be achieved with an inner covering of substantially uniform thickness.

While <FIG> above show a particular configuration for a three-layer contact lens able to accommodate a thick payload while providing adequate oxygenation to the eye (e.g., where the core <NUM> has a base surface <NUM> that mounts to the sclera of the eye when the contact lens is worn), it is understood that other configurations may be used. For example, in some embodiments, a contact lens may comprise a core, an outer covering (which may also be referred to as a "cap"), and an inner covering (also referred to as a "base"), in which the inner covering or base is formed is formed to support the contact lens on the sclera of the eye, instead of the core supporting the contact lens on the sclera as illustrated in <FIG>. Examples of this type of configuration are discussed in relation to <FIG> below.

<FIG> is a simplified perspective view of a three layer contact lens <NUM> able to accommodate a thick payload (e.g., greater than <NUM> thick), in accordance with some embodiments. As illustrated in <FIG>, the contact lens <NUM> comprises a cap <NUM>, a core <NUM>, and a base <NUM>. The cap <NUM> is positioned adjacent to an outer surface of the core <NUM>, while the base <NUM> is positioned adjacent to an inner surface of the core <NUM>. Together, the cap <NUM>, core <NUM>, and base <NUM> correspond to the three layers of the three layer contact lens <NUM>. When worn by a wearer, the base <NUM> is positioned adjacent to the wearer's eye (cornea and sclera) and separated from the surface of the wearer's eye by a tear layer, while the cap <NUM> and portions of the core <NUM> are exposed to air (except when the wearer closes their eye or blinks).

The cap <NUM>, core <NUM>, and base <NUM> are shaped such that when the contact lens <NUM> is assembled, an outer air gap <NUM> is formed between the cap <NUM> and the core <NUM>, and an inner air gap <NUM> is formed between the core <NUM> and the base <NUM>. Because the outer and inner air gaps <NUM> and <NUM> are each entirely enclosed by their respective structures, the outer and inner air gaps are not directly exposed to the external environment, preventing any debris or other contaminants from the outside air or from the tear layer from potentially reaching the outer air gap <NUM> or inner air gap <NUM>.

Similar to the outer covering <NUM>, inner covering <NUM>, and core <NUM> of the contact lens illustrated in <FIG>, the cap <NUM> and base <NUM> of the contact lens <NUM> are each relatively thin in comparison to the core <NUM>, and are made of materials that are permeable to oxygen such as RGP plastic, while the core <NUM> is sufficiently thick to accommodate a desired payload, such as a femtoprojector or one or more other types of electronic components. The cap <NUM> may have an annular shape, such that when the cap <NUM> is placed over the core <NUM>, the cap <NUM> covers only areas within the peripheral zones of the core, while leaving the central zone of the core <NUM> exposed to the air.

The cap <NUM> is exposed to air or separated from air by a thin tear layer (typically about <NUM> in thickness) that forms over the cap <NUM>. As such, oxygen is able to diffuse from the surrounding air through the gas permeable material of the cap <NUM> (and thin tear layer) to reach the outer air gap <NUM>. The oxygen collected in the outer air gap <NUM> is then able to diffuse rapidly through one or more air passages <NUM> (not shown in <FIG>) through the core <NUM> to traverse through the thickness of the core <NUM> to reach the inner air gap <NUM>. From the inner air gap <NUM>, oxygen diffuses through the gas permeable material of the base <NUM> to reach the tear fluid layer and underlying cornea of the wearer. Because the inner air gap <NUM> may be configured to cover a large portion of the wearer's cornea, oxygen may be substantially evenly distributed across the wearer's cornea through the base <NUM>. As with the contact lens <NUM> illustrated in <FIG>, the oxygen transmissibility of the contact lens <NUM> is defined primarily by the thicknesses of the cap <NUM> and base <NUM>, and not by thickness of the outer air gap <NUM>, inner air gap <NUM>, or the core <NUM>, allowing for the thickness and material of the core <NUM> to be selected to be able to accommodate a desired payload and provide sufficient structural strength to support the payload.

<FIG> illustrates a more detailed exploded view of the components of the three-layer contact lens <NUM>, in accordance with some embodiments. <FIG> shows a more detailed cross-sectional view of the three-layer contact lens <NUM>, in accordance with some embodiments. As illustrated in <FIG> and <FIG>, the cap <NUM>, core <NUM>, and base <NUM> are overlaid on top of each other to form the contact lens <NUM>, and may be aligned using one or more registration features. For example, the cap <NUM> may comprise a first registration feature 912a and a second registration feature 912b configured to interface with corresponding registration features of the core <NUM>. In some embodiments, the first registration feature 912a corresponds to a radius of the center hole of the cap <NUM>, while the second registration feature 912b corresponds to a peripheral radius of the cap <NUM>. The base <NUM> may comprise a registration feature 912c configured to interface with a corresponding registration feature of the core <NUM>.

As illustrated in <FIG>, the cap <NUM> and the core <NUM> are shaped to define the outer air gap <NUM> between the cap <NUM> and core <NUM>. In addition, the cap <NUM> and core <NUM> are shaped such that an outer surface of the cap <NUM> aligns with an outer surface of the core <NUM> in the central zone when the cap <NUM> is placed over the core <NUM>, in order for the collective outer surface of the contact lens <NUM> as defined by the cap <NUM> and core <NUM> to be substantially smooth, and not have protrusions or discontinuities. For example, the core <NUM> may have a first thickness t1 in the central zone, and a second thickness t2 in portions of the peripheral zone that is less than the first thickness t1. When the cap <NUM> is placed over the area of the peripheral zone having the second thickness t2, the outer surface of the cap <NUM> will aligns with the outer surface of the core <NUM> in the central zone having the first thickness t1. In addition, the cap <NUM> and the core <NUM> are further shaped such that a bottom surface of the cap <NUM> is spaced apart from an outer surface of the core <NUM> when the cap <NUM> is placed over the core <NUM>, creating the outer air gap <NUM> between the core <NUM> and the cap <NUM>.

In some embodiments, at least one of the cap <NUM> and the core <NUM> has a non-uniform thickness between the registration features 912a/b in order to define the outer air gap <NUM> between the cap <NUM> and the core <NUM>. Similarly, the base <NUM> may have a non-uniform thickness in order to define the inner air gap <NUM> between the base <NUM> and the core <NUM>. For example, as illustrated in <FIG>, the inner surface of the core <NUM> may be substantially smooth, while the thickness of the base <NUM> varies between the registration feature 912c and the central axis of the contact lens so as to form a space between the base <NUM> and the inner surface of the core <NUM>, defining the inner air gap <NUM> when the base <NUM> and core <NUM> are attached to each other.

In some embodiments, the core <NUM> comprises one or more features for accommodating one or more payload components. For example, as illustrated in <FIG>, the core <NUM> has a through-hole 914a within the central zone of the core for accommodating an electrical device such as a femtoprojector. The femtoprojector may be placed within the through-hole 914a and secured using an encapsulating material, which functions both to fix the position of the femtoprojector and to protect the femtoprojector from the outside environment.

In addition, the core <NUM> may comprise one or more payload features 914b in a peripheral region of the core, to accommodate one or more additional payload components. For example, the payload feature 914b may be in the form of a groove formed around a circumference of the core <NUM>, having a depth sufficient for winding the power coil around the core <NUM>, such that the power coil does not protrude from the payload feature 914b. The core <NUM> may further comprise additional payload features for accommodating additional payload components <NUM> (e.g., as illustrated in <FIG>), wiring or electrical connections between payload components, etc..

In some embodiments, the payload feature 914b within the peripheral region of the core <NUM> is located under the outer air gap <NUM> when the cap <NUM> is placed over the core <NUM>. In some embodiments, the payload components (e.g., power coil) within the payload features may be encapsulated in an adhesive or other material such that the components are not exposed to the air within the outer air gap <NUM>. In other embodiments, the payload components are exposed to the air within the outer air gap <NUM>. For example, as illustrated in <FIG>, the payload feature 914b may be located under the cap <NUM>, such that the payload <NUM> (e.g., a power coil) is located within the outer air gap <NUM>. This enables payload components within the core to be located in the periphery areas of the core. In some embodiments, the core <NUM> may contain at least one payload component closer to the center of the core <NUM> in comparison to the one or more air passages <NUM> traversing the core, and at least one payload component further from the center than the one or more air passages <NUM>.

While <FIG> illustrates certain payload features in the periphery regions of the core <NUM> being formed on the outer surface of the core <NUM> (e.g., payload feature 914b), in some embodiments, one or more of the payload features may be formed on the inner surface of the periphery region of the core <NUM>.

While <FIG> illustrates some payload features formed on areas of the core overlapping the cap (e.g., payload feature 214b formed under the cap <NUM>), in embodiments where an interface between the core and the outer covering / cap comprises a patterned structure (e.g., on the inner surface of the outer covering, or on the outer surface of the core), such that that illustrated in <FIG>, portions of the outer surface of the core on which the payload features may be formed may be restricted to portions that do not overlap with the patterned structure. However, because the use of a patterned structure may potentially reduce a surface area on the core covered by the outer covering / cap, additional surface area on the core not overlapping with the outer covering / cap may be available for forming payload features for accommodating payload components. In addition, in some embodiments where the patterned structure corresponds to only a portion of the outer covering, one or more payload features may be formed in portions of the core overlapping the outer covering but not overlapping with the patterned structure.

The air passages <NUM> are formed within the core <NUM>, and traverse the thickness of the core <NUM> to connect the outer air gap <NUM> to the inner air gap <NUM>. Because the outer air gap <NUM> does not extend over the central zone of the core <NUM>, the air passages <NUM> are formed in the peripheral zones of the core <NUM>. In some embodiments, as illustrated in <FIG>, the air passages <NUM> are oriented to be substantially perpendicular to the outer and inner surfaces of the core <NUM>, and connect laterally overlapping portions of the outer air gap <NUM> and inner air gap <NUM>. As used herein, two entities may be referred to as "laterally overlapping" if they intersect a common line perpendicular to the outer surface of the contact lens <NUM>.

In some embodiments, each of the air passages is substantially cylindrical in shape (e.g., having a circular cross-section). However, in other embodiments, the air passages <NUM> may have different shapes (e.g., different shaped cross-sections). The cross-sectional area of the air passages <NUM> is configured to allow for an amount of air flow between the outer and inner air gaps that is sufficient for oxygenating the cornea of the wearer's eye.

In some embodiments, the base <NUM> comprises one or more support features <NUM> to provide structural support to the inner air gap <NUM>. Because the inner air gap <NUM> may extend over both the central zone and periphery areas of the core <NUM> in order to allow for more even distribution of oxygen through the base <NUM> to reach the wearer's cornea, support features <NUM> within the inner air gap <NUM> may be useful for maintaining gap distance and overall structural integrity of the contact lens. The support features <NUM> may comprise one or more ridges or protrusions. For example, as illustrated in <FIG> and <FIG>, the support feature <NUM> comprises a ridge protruding from the outer surface of the base <NUM> located at a particular radius from a central axis of the base <NUM>. In some embodiments, the radius of the support feature <NUM> may be similar to the radius of the center hole of the annular cap <NUM>. However, in order to avoid blocking oxygen flow within the inner air gap <NUM>, the support feature <NUM> may extend only partway through the height of the inner air gap <NUM> (e.g., such that air can flow over the support feature <NUM>), be discontinuous (e.g., not extending all the way around in a circle), or some combination thereof. Even if the support feature <NUM> does not extend all the way across the inner air gap <NUM> to contact an opposing surface (e.g., the inner surface of the core <NUM>), the support feature <NUM> may still function to limit an amount of deformation of the base <NUM> and the inner air gap <NUM>.

In some embodiments, instead of or in addition to support feature <NUM>, the inner air gap <NUM> may contain one or more spacers (not shown), such as plastic micro balls, cylindrical or rectangular posts, etc., placed between the core <NUM> and the base <NUM> to help maintain the structural integrity of the contact lens and maintain gap distance of the inner air gap <NUM>. In addition, in some embodiments, the support feature <NUM> may be formed as part of the inner surface of the core <NUM> instead of or in addition to on the outer surface of the base <NUM>. In some embodiments, the core <NUM> and/or the cap <NUM> may have one or more support features for providing structural support for the outer air gap <NUM>. In some embodiments, the one or more support structures may extend along a radius of the cap <NUM>, core <NUM>, or cap <NUM>. In some embodiments, at least one of the inner surface of the cap <NUM> and the outer surface of the base <NUM> comprises a matrix of grooves, in which the outer or inner air gap is defined by the space between the grooves and the core <NUM>, the remaining portions of the surface of the cap or core serving as support features. In some embodiments, the support features may comprise a patterned structure comprising a plurality of recesses interspersed between a plurality of supports, such as those illustrated in <FIG>.

In some embodiments, the components of the contact lens (the cap <NUM>, core <NUM>, and base <NUM>) are manufactured separately and assembled together at a later time. For example, the cap <NUM>, core <NUM>, and base <NUM> may each correspond to a prefabricated component. In some embodiments, the cap, core and base are assembled together using an adhesive. One or more interfaces may be formed on these parts in order to ensure proper alignment and a reliable adhesive bond line for assembling the parts together. For example, the cap may be aligned with the core at an alignment stop surface. The cap includes a protrusion that displaces glue deposited in a recess formed in the core. The displacement forms a controlled thickness bond line of glue on one side of the protrusion while some glue flows just to an outer surface of the contact lens through capillary action. This allows for the parts to be assembled together without the glue overflowing if more than an ideal amount of glue is deposited.

<FIG> shows a cross-sectional view of a three-layer contact lens, in accordance with some embodiments. As discussed above, the components corresponding to the layers of the contact lens (i.e., cap, core, and base) may be manufactured separately and connected to each other using an adhesive material such as glue. The cap, core, and base may contact each other at one or more glue interfaces. For example, as illustrated in <FIG>, a peripheral edge of the cap <NUM> connects to the core <NUM> at a first interface <NUM>, while a central edge of the cap <NUM> connects to the core <NUM> at the central interface <NUM>. On the other hand, a peripheral edge of the core <NUM> connects to the base <NUM> at a second interface <NUM>.

<FIG> illustrates a more detailed view of region D of <FIG>, which includes the first interface <NUM> between the cap and core, and second interface <NUM> between the core and base. <FIG> illustrates a more detailed view of region E of <FIG>, which includes the central interface <NUM> connecting the cap to the core of the contact lens. Each of the glue interface <NUM>, <NUM>, and <NUM> comprises features to align the respective components being connected, as well as one or more features for controlling the flow of glue between the components, such that glue is prevented from overflowing from the interface onto the outer surfaces of the contact lens, even if more than an ideal amount of glue is deposited between the components at the glue interface.

The first glue interface <NUM>, as illustrated in <FIG>, comprises a reservoir <NUM>, a displacer <NUM>, and a wick <NUM>. The displacer <NUM> is formed as a convex feature (e.g., a protrusion or ridge) on the cap <NUM>, while a corresponding concave feature (e.g., a depression or groove) is formed on the core <NUM>. In addition, a portion of the inner surface of the cap <NUM> and a portion of the outer surface of the core <NUM> (hereinafter, "alignment surfaces") may function as an alignment stop <NUM> that aligns the cap <NUM> to the core <NUM> when the cap <NUM> is placed over the core <NUM>.

Prior to assembly, an amount of glue is placed into the concave feature formed on the core <NUM> (hereinafter referred to as the "recess"). When the cap <NUM> is placed on the core <NUM>, the alignment surfaces of the cap <NUM> and the core <NUM> contact each other to form the alignment stop <NUM> and radially align the cap <NUM> and core <NUM> relative to each other. In addition, the alignment surfaces may be shaped such that the stop <NUM> also aligns cap <NUM> to the core <NUM> in an axial direction.

When the cap <NUM> and the core <NUM> are aligned, the displacer <NUM> on the cap <NUM> aligns with the corresponding recess on the core <NUM>, and displaces glue from the recess. At least a portion of the displaced glue is drawn up the wick <NUM>, which is formed as the narrowing gap between the surfaces of the cap <NUM> and core <NUM> as the cap <NUM> is aligned with the core <NUM>. The displaced glue is drawn up the wick <NUM> towards a seam at the outer surfaces of the cap <NUM> and the core <NUM> through surface tension and capillary action.

The recess is larger than the displacer <NUM>, such that when the displacer <NUM> is positioned within the recess, a reservoir <NUM> is formed on a side of the displayer <NUM> opposite from the wick <NUM> to accommodate any excess glue that would otherwise flow past the seam between the cap <NUM> and core <NUM>. For example, the reservoir <NUM> of first glue interface <NUM> illustrated in <FIG> may include excess space on a side of the displacer <NUM> opposite from the wick <NUM>, allowing for any excess glue to flow in a direction opposite from and away from the wick <NUM>. Thus, the displacer <NUM> may divide the glue into a first amount that flows through the wick <NUM>, and a second excess amount that remains in the reservoir <NUM> on the opposite side of the displacer <NUM> as the wick <NUM>, ensuring that the excess glue is not pushed past the seam between the cap <NUM> and core <NUM>.

The second glue interface <NUM> may be constructed similarly to the first glue interface <NUM> as described above. For example, the second glue interface <NUM> may be formed by a displacer of the core <NUM> being aligned with (e.g., through corresponding alignment surfaces of the core <NUM> and base <NUM>) a corresponding recess on the base <NUM>. When the displacer of the core is placed within the reservoir of the base, at least a portion of the glue within the reservoir flows into the wick formed by the gap between the core and base, while a remaining excess portion of the glue is pushed into a reservoir formed on an opposite side of the displacer as the wick.

As illustrated in <FIG>, due to the annular shape of the cap <NUM>, the cap <NUM> may be attached to the core <NUM> via at least two different glue interfaces (e.g., the central interface <NUM> and a peripheral interface (corresponding to the first interface <NUM> described above). In some embodiments, the displacer <NUM> of the central interface <NUM>, as illustrated in <FIG>, is substantially wedge-shaped, having a first surface that serves as an alignment surface for the cap <NUM> for aligning with a corresponding alignment surface of the core <NUM> to form the alignment stop <NUM>, and a second surface that aligns with a second surface of the core <NUM> to form the wick <NUM>. As illustrated in <FIG>, the reservoir <NUM> may be formed on the same side of the displacer <NUM> as the wick <NUM>. When the cap <NUM> is placed over the core <NUM>, the displacer <NUM> aligns with a recess formed on the core <NUM>, and pushes glue that has been deposited within the recess towards the wick <NUM> and a seam formed between the cap <NUM> and the core <NUM>. In addition, any excess amount of glue that may have been deposited within the recess remains within the reservoir <NUM> formed between the displacer <NUM> and the recess, preventing glue from overflowing from the seam.

While <FIG> and <FIG> illustrate the displacer and reservoir for each glue interface located on particular components, in other embodiments, the displacer and reservoir may be formed on different components. For example, in some embodiments, the reservoir of the first glue interface <NUM> may be formed on the cap <NUM>, and the displacer on the core <NUM>. Which component the reservoir and displacer are formed on may be based upon an expected orientation of the contact lens during assembly.

<FIG> shows a cross-sectional view of a three-layer contact lens having another structural interface between the cap, core, and base of a contact lens, in accordance with some embodiments. As illustrated in <FIG>, the cap, core, and base are positioned such that both the cap <NUM> and the core <NUM> are placed on a single surface of the base <NUM>. This allows for the cap <NUM>, core <NUM>, and base <NUM> to be assembled with one less seam on the outer surface of the contact lens, in comparison to the configuration illustrated in <FIG> and <FIG>.

<FIG> shows a more detailed view of region A of <FIG>, containing the glue interface <NUM>. At the glue interface <NUM>, the base <NUM> may have an alignment surface configured to form an alignment stop 1112B with the core <NUM>, in order to align the core <NUM> with the base <NUM>. The base <NUM> may also have formed thereon a pair of recesses into which glue can be deposited.

Each of the cap <NUM> and the core <NUM> may have formed thereon a respective displacer 1108A and1108B configured to fit into a respective recess of the base <NUM>. In addition, the cap <NUM> and core <NUM> each have alignment surfaces forming an alignment stop 1112A between them for aligning the cap <NUM> with the core <NUM>. As such, when the core <NUM> is placed over and aligned with the base <NUM> using the alignment stop 1112B, and the cap <NUM> is placed over and aligned with the core <NUM> using the alignment stop 1112A, the cap <NUM> will be aligned with the base <NUM>, such that the displacer 1108A of the cap <NUM> is positioned within its corresponding recess on the base <NUM>.

When the cap <NUM> and core <NUM> are placed over the base <NUM>, a wick <NUM> is formed on one side of the displacer 1108A of the cap <NUM> by the surfaces of the cap <NUM> and the base <NUM>. A portion of the glue in the recess flows into the wick <NUM> through surface tension and capillary action. However, a remaining excess amount of glue is pushed by the displacer <NUM>08A into the reservoir 1106A on the opposite side of the displacer <NUM>08A as the wick <NUM>, allowing for the wick <NUM> to receive only an amount of glue needed to fill the seam between the cap <NUM> and the base <NUM> without having glue flow over the seam, even if more than an ideal amount of glue was deposited in the recess on the base <NUM>.

The displacer 1108B of the core <NUM> displaces the glue deposited within the corresponding recess on the base <NUM>. For example, a first amount of glue flows into the wick <NUM> formed between the core <NUM> and the base <NUM>. In addition, a second amount of excess glue is pushed by the displacer 1108B into the reservoir 1106B.

In some embodiments, the core <NUM>, cap <NUM>, and base <NUM> are shaped such that a gap volume <NUM> is formed between the core <NUM>, cap <NUM>, and base <NUM>. The gap volume <NUM> is part of the reservoir 1106A and is able to receive excess glue displaced by the displacer 1108A. In addition, because the interface between the core <NUM> and the base <NUM> does not include a seam on the outer surface of the contact lens, the displacer 1108B may push excess glue into the reservoir 1106B or into the the gap volume <NUM>.

In some embodiments, attaching the cap <NUM> and core <NUM> onto a single surface of the base <NUM> (as illustrated in <FIG> and <FIG>) may allow for a greater tolerance of excess glue, due to the gap volume <NUM> that can be formed between the cap <NUM> and the core <NUM>. In addition, the resulting contact lens will only have one seam on the outer surface of the lens (e.g., a seam between the cap <NUM> and the base <NUM>, potentially reducing a chance for outside contaminants (e.g., dust, tear fluid, etc.) to enter the contact lens through a seam.

As such, the components of the contact lens may be connected via one or more glue interfaces, where each glue interface comprising a protrusion that displaces glue deposited in a recess such that a first amount of glue flows to a seam formed between the components, and a second excess amount of glue is displaced into an excess reservoir volume, preventing overflow of glue beyond the outer surface of the contact lens, even if more than an ideal amount of glue is deposited.

While <FIG> and <FIG> illustrate glue interfaces structures that may be used to attach the cap <NUM>, core <NUM>, and base <NUM> in contact lenses where the base <NUM> mounts to the sclera of the wearer's eye, it is understood that the glue interface structures discussed above can be used in contact lens having other configurations, such as contact lenses in which the core comprises a base surface that mounts to the sclera of the wearer's eye (e.g., as illustrated in <FIG>). For example, in some embodiments, the outer covering <NUM> may be attached to the core <NUM> using glue interface structures similar to of interfaces <NUM> and <NUM> illustrated in <FIG>. In addition, the inner covering <NUM> may be attached to the core <NUM> using a glue interface structure similar to that of the interface <NUM>, but where the wick <NUM> faces a seam between the inner surfaces of the inner covering <NUM> and core <NUM>, instead of the outer surfaces as illustrated in <FIG>.

In some embodiments, instead of being attached using glue, the components of the contact lens may be place together using a friction fit or a snap-on fit. For example, in some embodiments, the displacer of a first component may have one or more features configured to snap onto one or more features within a recess on a second component, allowing for the components to be assembled together without glue. In other embodiments, the components of the contact lens may be attached together using a laser weld or an ultrasonic bond.

<FIG> shows a top down view of a contact lens, in which the outer covering is divided into separate pieces. While previous figures have illustrated the outer covering or (e.g., outer covering <NUM> illustrated in <FIG>, cap <NUM> as illustrated in <FIG>) as a single annular piece, in some embodiments, the outer covering may have several separate pieces. In <FIG>, the outer covering <NUM> is divided into four separate pieces 1220A-D. When placed over the core <NUM>, each of the outer covering pieces 1220A-D forms a separate outer air gap between it and the core <NUM>, each of which is connected to the inner air gap via an air path. While <FIG> shows a space between each of the outer covering pieces 1220A-D, in some embodiments, the outer covering pieces 1220A-D directly abut each other when placed over the core <NUM>. Using separate pieces can reduce the mechanical stress on each piece.

<FIG> shows an oval scleral contact lens display mounted on a user's eye. The contact lens <NUM> has a non-circular perimeter <NUM> and extends below the upper and lower eyelids. In this example, the contact lens <NUM> has an "oval" perimeter <NUM> that is elongated along the direction of the eye opening. Due to the curvature of the eye, the actual shape of the perimeter is three-dimensional. However, for convenience, it will be referred to as oval. Due to the size of the contact lens <NUM>, it is partially covered by the user's eyelids. <FIG> also shows the contact lens <NUM> carrying a payload, which may comprise a set of femtoprojectors <NUM>, electronics <NUM>, and coil <NUM>.

One advantage of a non-circular perimeter is that the contact lens is larger and has more space to carry payloads. Another advantage is that the perimeter is larger so that larger coils <NUM> may be used. For example, the conductive coil <NUM> may be constructed so that it lies parallel to and within <NUM> to <NUM> of the perimeter <NUM> (e.g., the coil <NUM> lies within <NUM> of the perimeter <NUM>). Although the contact lens is larger with a non-circular perimeter, the inner covering and inner air gap may have the same circular size and shape as described previously since that is sufficient to oxygenate the cornea.

The foregoing description of the embodiments of the invention has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but merely illustrates different examples. It should be appreciated that the scope of the disclosure includes other embodiments not discussed in detail above. Therefore, the scope of the invention should be determined by the appended claims.

Claim 1:
A scleral contact lens (<NUM>) that mounts to a sclera (<NUM>) of an eye (<NUM>), comprising:
a core (<NUM>) having an outer surface (<NUM>) that faces outwards away from the eye, and an inner surface (<NUM>) that faces inwards towards a cornea (<NUM>) of the eye; the core carrying a payload;
a gas-permeable outer covering (<NUM>) over the core's outer surface, the outer covering and the core's outer surface forming an outer interstital cavity (<NUM>) therebetween that receives oxygen from the external environment through the gas-permeable outer covering; and
a gas-permeable inner covering (<NUM>) under the core's inner surface and disposed over the cornea of the eye, the inner covering and the core's inner surface forming an inner interstital cavity (<NUM>) therebetween that passes oxygen to the cornea of the eye through the gas-permeable inner covering;
wherein the core contains an air path (<NUM>) traversing the core from the outer interstital cavity to the inner interstital cavity;
wherein at least one of the core's outer surface and the outer covering's inner surface comprises a patterned structure, the patterned structure has a plurality of recesses interspersed with a plurality of supports, the core and outer covering contact each other at the supports, and the recesses form the outer interstital cavity; and
wherein the patterned structure comprises a pattern of blind holes, and wherein the pattern of blind holes comprises:
a first plurality of non-overlapping blind holes (<NUM>), each having a first depth and a first radius; and
a second plurality of blind holes (<NUM>) overlaying the first plurality of blind holes, each having a second depth shallower than the first depth and a second radius larger than the first radius, wherein the second plurality of blind holes overlap with each other to form a plurality of columns (<NUM>) between the first plurality of blind holes.