Field of the Present Disclosure

The present disclosure concerns ophthalmic lenses. More particularly, but not exclusively, this present disclosure concerns tuneable ophthalmic lenses. The present disclosure also concerns a method of tuning an ophthalmic lens.

Background of the Invention

A significant number of people suffer from vision defects, for example myopia (short sightedness) and hyperopia (long sightedness). As people get older, they may develop presbyopia (where the lens becomes less elastic which makes it more difficult for the eye to accommodate i.e. increase its focussing power to focus on near objects). A common way of correcting the vision in this situation is the use of varifocal eyeglasses. These glasses have a different focal length near the top of the lens compared with the bottom of the lens; however, this means that vision through part of the lens is always out of focus depending on the activity of the wearer, and as such many people opt for two separate pairs of glasses: one for near sight and one for far sight. Else, the wearer has to angle their eyes or head in order to use the different parts of the lens.

Conventional ophthalmic lenses are set at a specific power that is determined when the ophthalmic lens is manufactured, and as such are often unable to remedy the above issue by themselves. Some alternative conventional ophthalmic lenses have been designed to overcome this problem. One way is for each contact lens of a contact lens pair to have a different power. For example, the contact lens in the left eye might have a power for distance vision, and the contact lens in the right eye might have a power for near vision. This is termed ‘monovision ’ as the wearer of this type of contact lens system no longer has binocular vision, which is a problem. Another alternative design is to have a contact lens with a central optical zone that encompasses parts of the contact lens with different powers. For example, the centre of the central optical zone might have a power for near vision, and a ring shaped region around the centre (still within the central optical zone) may have a power for distance vision. This produces two images on the retina, and the neural optical pathways of the wearer are required to select which image to Took’ at. Some variants of this have more than one zone of each power. Many wearers complain of problems including ghosting when using contact lenses of this variety. It would therefore be desirable to have an ophthalmic lens that is capable of adjusting its power, not only for near and far sight, but also for when the strength of correction required by the eye changes with time.

Ophthalmic lenses have been proposed that have a central chamber that is filled with fluid. US 2014/0002789 discloses a contact lens that has a central chamber that comprises a cavity. The contact lens of the prior art uses electrowetting to fill the cavity either with a first fluid of a first refractive index, or with a second fluid of a second refractive index. This enables the wearer to discretely switch between two predetermined strengths. This does not allow for continuous fine-tuning or adjustment of the strength of the lens, however.

The present disclosure seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present disclosure seeks to provide an improved tuneable ophthalmic lens.

Summary of the Present Disclosure

The present disclosure provides, according to a first aspect, a tuneable ophthalmic lens as claimed in claim 1.

According to a second aspect of the present disclosure, there is also provided a method of tuning an ophthalmic lens as claimed in claim 9.

According to a third aspect of the present disclosure, there is also provided a method of manufacturing a tuneable ophthalmic lens as claimed in claim 14.

According to a fourth aspect of the present disclosure, there is also provided a kit of parts as claimed in claim 19. Preferred but optional features of the disclosure are set out in the dependent claims.

It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the invention may incorporate any of the features described with reference to the apparatus of the invention and vice versa.

Description of the Drawings

Embodiments of the present disclosure will now be described by way of example only with reference to the accompanying schematic drawings of which:

FIG. la shows a front view of a tuneable contact lens in a first state according to an embodiment of the present disclosure.

FIG. lb shows a front view of a tuneable contact lens in a second state according to an embodiment of the present disclosure.

FIG. lc shows a front view of a tuneable contact lens in a third state according to an embodiment of the present disclosure.

FIG. Id shows a front view of a tuneable contact lens in a fourth state according to an embodiment of the present disclosure.

FIG. 2 shows a flowchart of a method of manufacturing an ophthalmic lens according to an embodiment of the present disclosure.

FIG. 3 shows a schematic diagram of a method of tuning an ophthalmic lens according to an embodiment of the present disclosure.

Detailed Description

The present disclosure will be more fully understood and further advantages will become apparent when reference is made to the following detailed description of embodiments of the present disclosure, wherein like reference numeral denote similar elements. Note that the figures are not to scale. In the following description, the terms “first lens portion” and “second lens portion” refer to portions that form part of an ophthalmic lens. Optionally, first lens portion is not a lens, i.e. the power of first lens portion may be substantially zero. Optionally, second lens portion is not a lens, i.e. the power of second lens portion may be substantially zero. When specifically in reference to contact lenses, the first lens portion refers to the portion that makes up the contact lens that is in contact with an eyeball when the contact lens is in use. The second lens portion, when in reference to contact lenses, refers to the portion, which makes up the contact lens, which forms part of the external curvature of the contact lens, when the contact lens is in use on an eye.

The term “central optical zone” refers to the region of the ophthalmic lens that is configured to be positioned over the pupil of an eye when in use. The central optical zone may encompass a portion of the central chamber. The central optical zone may encompass the entirety of the central chamber. The central optical zone may encompass the entirety of the central chamber, and a part of the second lens portion.

As set out above, the first aspect of the present disclosure provides according to a first aspect a tuneable ophthalmic lens. The tuneable ophthalmic lens comprises a central chamber. The tuneable ophthalmic lens further comprises a first fluid reservoir. The first fluid reservoir is in fluid communication with the central chamber. The first fluid reservoir contains a first fluid of a first refractive index. The tuneable ophthalmic lens also comprises a second fluid reservoir. The second fluid reservoir is in fluid communication with the central chamber. The second fluid reservoir contains a second fluid of a second refractive index. At least one fluid reservoir includes a pumping mechanism. The pumping mechanism is suitable for pumping each of the first and second fluids between the central chamber and the first and second fluid reservoirs respectively. The first and second fluids are immiscible.

The boundary of the central chamber may be defined by a circumferential wall and an anterior surface, which may be an external surface of the lens. The boundary of the central chamber may also be defined by a surface of the first lens portion. The central chamber contains fluid. The fluid may either be the first fluid, or the second fluid, or a combination of the first and second fluid. Both of the fluid reservoirs being in fluid communication with the central chamber means that the correct volume of both liquids can be pumped by the pumping mechanism between the fluid reservoirs and the central chamber.

The overall volume of fluid in the central chamber may remain constant. Therefore, when a volume of the first fluid is pumped out of the central chamber, for example, the same volume of the second fluid may be pumped into the central chamber.

The first fluid and the second fluid are immiscible. This advantageously means that there is reduced risk of the second fluid entering the reservoir designated for the first fluid, and vice versa. This is beneficial because should the fluids mix, it would become difficult to vary the optical strength of the ophthalmic lens. The first fluid may be oil based, and the second fluid may be water based. The first fluid may be water based, and the second fluid may be oil based.

The ophthalmic lens may initially be in a state where the central chamber is completely filled with the second fluid. When the optical strength of the ophthalmic lens is needed to be changed, upon receipt of an instruction for example, the pumping mechanism in the first fluid reservoir may pump fluid out of the first reservoir and into the central chamber. Simultaneously, the pumping mechanism of the second fluid reservoir may pump the second fluid out of the central chamber and into the second fluid reservoir. In some embodiments of the present disclosure, the force of the first fluid being pumped and entering the central chamber forces the second fluid out of the central chamber, without the need for pumping the second fluid out of the central chamber. This pumping of the first fluid into the central chamber may be at the same volumetric flow-rate that the second fluid is being pumped out of the central chamber. The central chamber may become completely filled with the first fluid. The central chamber may become partially filled with the first fluid, and as such the central chamber may have a combination of the two immiscible fluids present in the central chamber. The ratio of the volumes of first fluid to second fluid within the central chamber may determine the optical powers of the ophthalmic lens, the optical powers tunable by adjusting the ratio of volumes of the first and second fluids in the central chamber.

Thus, the pumping mechanism may be configured to at least partially fill the central chamber with the first fluid. The net refractive index of the central optical zone may be continuously variable. The net refractive index of the central optical zone may be a function of the ratio of volumes of the first and second fluids within the central chamber.

The ophthalmic lens may be configured to maintain a predetermined orientation on an eye, when in use. A ballast region may be configured to ensure that the ophthalmic lens is maintained in the predetermined orientation. The ballast region may ensure that the ophthalmic lens remains in a specified orientation on the eye.

The ballast region may comprise a thicker portion of the periphery of the ophthalmic lens. In this manner, whenever the wearer of the ophthalmic lens blinks, the force of the upper eyelid pushing down on the ballast region may orientate the ophthalmic lens in the predetermined orientation. The thicker portion of the periphery of the ophthalmic lens (the ballast region) may be tapered, with the thinnest portion of the ballast region being closest to the centre of the ophthalmic lens, and the thickest portion of the ballast region being furthest from the centre of the ophthalmic lens.

This way, the ballast region may ensure that it is always located on a lower portion of the ophthalmic lens, the lower portion being located in the bottom half of the ophthalmic lens. When in use, “bottom half’ refers to the half of the ophthalmic lens that is located below a horizontal plane, when the horizontal plane passes through the central axis of the ophthalmic lens. As used, top half of the ophthalmic lens refers the half of the ophthalmic lens that is above the central horizontal plane when the ophthalmic lens is on the eye. The skilled person will appreciate that there are alternative methods known in the art, compared to the use of ballast regions, for maintaining a contact lens in a particular orientation on the eye.

The first fluid reservoir may be located opposite the second fluid reservoir.

The first and second fluid reservoirs may be located on opposite portions of a circumference of the central chamber. The first fluid reservoir and the second fluid reservoir may have an approximately 180° angular displacement, relative to the centre of the central chamber. The first fluid reservoir may be located above the horizontal, and the second fluid reservoir may be located below the horizontal. When the ophthalmic lens is in use on an eye, the first fluid reservoir may be located above the central chamber, and the second fluid reservoir may be located below the central chamber. This may be advantageous in preventing one fluid from contaminating the reservoir of the other fluid. If the two reservoirs were adjacent each other, or on the same horizontal plane, then the two fluids may enter both reservoirs and it may become very difficult, or impossible, to completely empty the central chamber of one of the fluids.

The first fluid may be oil based. The second fluid may be water based, for example a saline solution. This exemplifies further advantages of embodiments of the present disclosure having one reservoir located above the other, as the first fluid may be a lower density than the second fluid. The difference in density would assist, along with the fluids being immiscible, in ensuring that the two fluids are kept separate, and that they do not enter the incorrect fluid reservoir.

The pumping mechanism(s) may include a wireless communication module. The wireless communication module may receive instructions. The instructions may control the pumping mechanism. The wireless communication module may be configured to communicate to a processor. The processor may be external to the ophthalmic lens. The processor may transmit instructions to the wireless communication module. The processor may receive manual inputs from a wearer of the ophthalmic lens. The processor may convert manual inputs into instructions, which are then transmitted to the wireless communication module. The communication between the processor and the wireless communication module may be performed over radio frequency.

The wearer may be able to input to the processor that they wish to see long distance, for example. The processor may be calibrated for the wearer, such that the wearer input is converted into an appropriate instruction for the pumping mechanism. The ratio of first and second fluids in the central chamber is then adjusted such that the wearer can see clearly at distance. The wearer may then be able to input into the processor that they wish to see close objects clearly, for example. The processor would then convert the wearer’s input into an appropriate instruction for the pumping mechanism. The ratio of first and second fluids the central chamber would then be adjusted such that the wearer can see in short distance.

The pumping mechanism(s) is a pump. The pumping mechanism(s) may be an osmotic pump. An osmotic pump does not require high voltages to operate, and so advantageously means that the ophthalmic lens will be operable for longer periods of time before a recharge is required. Osmotic pumps are also beneficial in that they are capable of accurately and precisely moving specific quantities of fluid across its osmotic membrane. The pumping mechanism(s) may be an actuator.

The ophthalmic lens may provide a distance power when the first fluid fills the central chamber and a near power when the second fluid fills the central chamber, or vice versa.

The ophthalmic lens may be arranged so that, in the event of failure of the pump (due to a power failure or otherwise), the first and second fluid revert to a state in which the ophthalmic lens provides a distance power. That arrangement ensures that the lens “fails safe”, which is important e.g. when driving. For example, the reservoir for the fluid providing the distance power may be arranged above the central chamber so that in the event of a power failure that fluid drains into the central chamber. The reservoir for the fluid providing the near power may be arranged below the central chamber so that in the event of a power failure that fluid drains out of the central chamber.

The central chamber may include a structure having a refractive index and forming a Fresnel lens, wherein the first or the second refractive index is the same as the refractive index of the structure. A structure forming a Fresnel lens has a plurality of protruding regions which act to focus light. The focusing of the light depends on there being a refractive index difference between the protruding regions of the structure and the material surrounding those regions (in this case, the fluid in the central chamber). Thus, when the fluid having the same refractive index as the Fresnel lens structure fills the central chamber, the fluid will fill the Fresnel lens structure between the protruding regions, removing the refractive index difference and thus eliminating the optical effect of (i.e. the focusing by) the Fresnel lens. Thus, by pumping the first and second fluid between the central chamber and the first and second fluid reservoirs, the power of the ophthalmic lens may be changed from a first, for example near, power, in which the Fresnel lens acts to focus light incident on the ophthalmic lens, to a second, for example distance, power, in which the optical effect of the Fresnel lens is eliminated.

As set out above the second aspect of this disclosure provides a method of tuning an ophthalmic lens. The ophthalmic lens comprises a central chamber. The ophthalmic lens also comprises a first fluid reservoir containing a first fluid of a first refractive index. The ophthalmic lens further comprises a second fluid reservoir containing a second fluid of a second refractive index. The method further comprises the step of pumping the first and second fluids between the first and second fluid reservoirs and the central chamber, to achieve a selected lens power.

The method may further comprise the step of determining a required ratio of first and second fluid in the central reservoir. The required ratio may be pre calibrated for the selected lens power. The selected lens power may correspond to a selected lens prescription. In embodiments, a plurality of selected lens prescriptions are pre-calibrated for example, a prescription for near vision and distance vision. For each of these prescriptions, a different ratio of fluids will be required in the central chamber. For example, the pre-calibrated ratio of fluids for a near vision prescription may be 100:0 of first fluid in the central chamber, i.e. the central chamber is completely filled with only one fluid.

The required ratio may be calculated by a processor. The processor may be external to the ophthalmic lens. The processor may receive inputs from the wearer. The processor may convert the wearer’s inputs into an instruction, or set of instructions, for the ophthalmic lens.

The method of tuning an ophthalmic lens may comprise receiving an instruction. The instruction may comprise the volume of first fluid to be removed from the central chamber. The instruction may comprise the volume of first fluid to be added to the central chamber. The instruction may comprise the volume of second fluid to be removed from the central chamber. The instruction may comprise the volume of second fluid to be added to the central chamber. The instruction may comprise the required ratio of volumes of first and second fluid in the central chamber. The ophthalmic lens, upon receipt of the instruction, may pump first and second fluids between the central chamber and their respective reservoirs to achieve the required power of the lens. The required power of the lens may be expressed as a ratio of volumes of the first and second fluid in the central chamber, such that the pumping mechanism is able to understand the instruction.

Preferably, the ophthalmic lens may be a contact lens. The ophthalmic lens may be an intraocular lens. As set out above, the third aspect of the present disclosure provides a method of manufacturing a tuneable ophthalmic lens according to the first aspect. The method comprises the step of forming a first lens portion. The method further comprises the step of forming a second lens portion. The method further comprises forming a central chamber, a first fluid reservoir, and a second fluid reservoir. At least one of the fluid reservoirs includes a pumping mechanism. The method further comprises coupling the second lens portion to the first lens portion, to form a tuneable ophthalmic lens.

The method may further comprise fluidly connecting each fluid reservoir to the central chamber.

Forming the second lens portion may comprise forming a recess on the first and/or the second lens portion. The recess may be plastically deformed. Forming the first and/or second lens portion may comprise forming a plurality of recesses on the second lens portion. The recess may form the central chamber. The plurality of recesses may form the central chamber and a first and second fluid reservoir.

The method may comprise at least partially filling the recess/recesses with fluid prior to the bonding step.

The skilled person will appreciate that the order of the steps presented are not necessarily the order in which they need to be performed, and is not intended to limit the scope of the claims. For example, it would be possible to form the second lens portion before forming the first lens portion.

As set out above the fourth aspect of the present disclosure provides a kit of parts comprising: (a) a tuneable ophthalmic lens as claimed in any of claims 1 to 7, the lens including a communication module; and (b) a control module for communicating with the communication module.

Figure la shows a front view of a tuneable contact lens 100 in a first state according to an embodiment of the present disclosure. The majority of contact lens 100 is comprised of first lens portion 102. First lens portion 102 is shaped to fit on the eye and has a concave rear surface (not visible in this view). First lens portion 102 is constructed out of silicone elastomer. In the centre of contact lens 100 is a central chamber 108. Central chamber 108 is filled with liquid. In the first state, as shown in Figure la, the central chamber 108 is filled exclusively with a first fluid 106a. The first fluid 106a is stored in first fluid reservoir 106. First fluid reservoir 106 includes a pumping mechanism (not shown). The skilled person would appreciate that the pumping mechanism may be any suitable mechanism for fine control of the volume of fluid in the reservoir. In embodiments of the present disclosure, the pumping mechanism is an osmotic pump. Osmotic pumps do not require high voltages or power to operate, and also allow for precise volume control.

The first fluid reservoir 106 is in fluid communication with central chamber 108. The fluid communication may be achieved by channels (which may be equipped with valves), or a porous membrane. Second fluid reservoir 110 is filled with second fluid 110a. Second fluid reservoir 110 is also in fluid communication with central chamber 108, and may be in fluid communication with central chamber 108 in the same or a similar manner as first fluid reservoir 106.

Contact lens 100 also comprises a ballast region 104. Ballast region 104 is positioned at the bottom of contact lens 100, and is integrally formed with first lens portion 102. Ballast region 104 is composed of the same material that makes up first lens portion 102. Ballast region 104 is wedge-shaped (in a side, cross-sectional view), such that it tapers, and it thinnest at its top and thickest at its bottom. As such, the thinnest portion of ballast region 104 is located closest to a notional horizontal line that passes through the centre of contact lens 100. The thickest portion of ballast region 104 is located furthest from the notional horizontal line that passes through the centre of contact lens 100. This shape of ballast region 104 is beneficial in maintaining contact lens 100 in a consistent orientation. When the upper eyelid moves down over contact lens 100, if contact lens 100 has rotated slightly, the force of the upper eyelid on ballast region 104 corrects the rotation and restores contact lens 100 to its correct orientation.

The skilled person will understand that there are alternative methods known in the art, compared to the use of ballast regions, for maintaining a contact lens in a particular orientation on the eye. The skilled person will also understand that there are alternative configurations for ballast regions known in the art, which are not wedge-shaped. Optionally, the ballast region is not wedge-shaped. Figure lb shows a front view of the tuneable contact lens 100 of Figure la in a second state according to the embodiment of Figure la. To achieve the second state as shown in Figure lb, the second fluid 110a has been pumped into the central chamber 108 and the first fluid 106a has been completely replaced by the second fluid 110a in the central chamber 108 . Instructions are sent to contact lens 100, to instruct contact lens 100 to switch between the first state and the second state. The instruction may comprise the volume of fluid to be added/removed from the central chamber.

The instruction may comprise switching a pump “on” or “off’. In embodiments of the present disclosure, the instruction specifies a voltage to be applied to the pump.

Second fluid 110a has a second refractive index, wherein the second refractive index is different to the first refractive index of first fluid 106a. Therefore, in the second state, contact lens 100, and more specifically central chamber 108, has a different optical strength/power compared to when in the first state. The central optical zone in the second state therefore also has a different power compared to when in the first state.

Figure lc shows a front, cross-sectional view of a tuneable contact lens 100 in a third state according to an embodiment of the present disclosure. In the third state, both the first and second fluids have been pumped into liquid filled region 108a of central chamber 108. In the embodiment of Figure lc, there is a concentration gradient of fluids from first fluid 106a to second fluid 110a. This is because the two fluids are only partially immiscible. The partial immiscibility may mean that a micro emulsion forms at the boundary between the first fluid 106a and second fluid 110a. The difference in densities of the two fluids assists in maintaining separation and preventing the incorrect fluid from entering the wrong reservoir. The ratio of volumes of first fluid 106a and second fluid 110a in liquid filled region 108a of central chamber 108 controls the optical power of central chamber 108 and contact lens 100. When adjusting the relative volumes of first fluid 106a and second fluid 110a in liquid filled region 108a of central chamber 108, the overall volume of liquid filled region 108a does not change. Therefore, the only changes that are made that induce a change in optical power/strength of contact lens 100 is the relative volumes of fluids 106a, 110a, which have different refractive indices. The shape of central chamber 108 is unchanged.

Figure Id shows a front, cross-sectional view of a tuneable contact lens 100 in a fourth state according to an embodiment of the present disclosure. In the fourth state, both the first and second fluids 106a, 110a have been pumped into liquid filled region 108a of central chamber 108. In the embodiment of Figure Id, there is no concentration gradient, and fluids 106a, 110a are completely immiscible. This creates a clear and definite boundary between the two fluids in liquid filled region 108a of central chamber 108. The difference in densities of the two fluids assists in maintaining separation and preventing the incorrect fluid from entering the wrong reservoir. The ratio of volumes of first fluid 106a and second fluid 110a in liquid filled region 108a of central chamber 108 controls the optical power of central chamber 108 and contact lens 100. When adjusting the relative volumes of first fluid 106a and second fluid 110a in liquid filled region 108a of central chamber 108, the overall volume of liquid filled region 108a does not change. Therefore, the only changes that are made that induce a change in optical power/strength of contact lens 100 is the relative volumes of fluids 106a, 110a, which have different refractive indices. The shape of central chamber 108 is unchanged.

The tuneable contact lens may receive an instruction in response to an input of a wearer of the contact lens. The input may comprise specifying distance vision for example. The input may comprise specifying near vision, for example. In embodiments of the present disclosure, the instruction comprises a ratio of the volumes of the first and second fluid to be present in the central optical zone. In embodiments of the present disclosure, the instruction specifies a voltage to be applied to the osmotic pump. A separate processor external to the contact lens may have converted a required optical power of the lens to a required volume ratio of fluids within the central chamber, and then converted this ratio of volumes to a required voltage across each osmotic pump that is comprised within each fluid reservoir 106, 110.

The following is an exemplary method of manufacture of a tuneable contact lens, according to an embodiment of the present disclosure. Figure 2 shows a flowchart of a method of manufacturing an ophthalmic lens according to an embodiment of the present disclosure.

The method comprises the step of forming a first lens portion. The first lens portion is formed of silicone hydrogel or silicone elastomer. The first lens portion is formed in a lens portion molding assembly, which comprises a first mold part and a second mold part assembled together. The first and second mold parts are formed in mold part forming step 202. Mold part forming uses meal dies. A surface of each of a pair of metal dies corresponds to a surface of a mold part to be formed. Considering that only one surface of the mold part to be formed is used in the formation of any of the contact lens components, the die used to form the other surface does not need to form a particular shape. One of the dies may be flat, for example. The other die may have a concave cavity. This forms a mold part with a convex anterior surface and a flat rear surface. Mold part forming 202 includes holding the dies together and injection molding a first mold part. A similar second pair of dies are used to form a second mold part, also by injection molding. The second pair of dies may include a die with a convex protrusion, while the second die of the second pair may be flat. The mold part formed in this second pair of dies would therefore have a concave surface and a flat (rear) surface.

Mold part forming step 202 also includes the formation of a pair of injection molded molds that are used to form a second lens portion. The steps for forming the pair of molds for forming the second lens portion are substantially the same as the steps for forming the pair of molds for forming the first lens portion. The injection molded molds for forming the second lens portion may be a different shape to the mold for forming the first lens portion.

In this example, the die forming the concave surface includes recesses that lead to the formation of recesses in the second lens portion, the recesses corresponding to the central chamber, the fluid reservoirs, and channels therebetween.

A dry first lens portion is then formed in first lens portion forming step 204a.

A dry second lens portion is also then formed in step 204b. The steps for the formation of both of these lens portions is substantially the same and is as follows. In the case of hydrogel members or silicone hydrogel members, the first lens portion (or second lens portion) can be made by polymerizing a hydrogel or silicone hydrogel lens formulation that includes a polymerization initiator in a first lens portion shaped cavity formed between the first mold part and the second mold part. For silicone elastomer members, the first lens portion can be made by curing, vulcanizing, or catalyzing, such as by hydrosylation, a liquid silicone elastomer material in a first lens portion shaped cavity formed between the first mold part and the second mold part. The surface of each mold part that forms the lens member shaped cavity may be convex, concave, planar or a combination of thereof. After formation of the first lens portion, the two mold parts are separated such that the first lens portion remains attached to the surface of one of the mold parts. As a result, a first lens portion is provided on a surface of the first or second mold part. In embodiments of the present disclosure, it is desirable to place the first lens portion on a surface of a mold part that was not used to produce the first lens portion, but that may require additional steps to achieve the desired alignment of the member to the mold part.

Washing steps 206a and 206b involve washing of the first lens portion and the second lens portion respectively. Any residue from the formation of the first lens portion and the second lens portion in the mold parts is washed off. Also in this step, the washing causes the dry lens portions to swell as water is retained within the membrane of the lens portions.

In a recess enhancing step 208, the second lens portion is held in a receptacle. A recess enhancing surface of a predetermined diameter is then pressed into the concave surface of the second lens portion to plastically deform the recess in the second lens portion that will go on to form the central chamber. The second lens portion is plastically deformed in the region of the central chamber so that the portion of the upper layer that forms the walls of the central chamber are not under stress when the central chamber is filled with fluid, when in use. It has been found that without plastically deforming the walls of the central chamber, when the central chamber is filled with fluid, the stress in the walls of the central chamber caused by the elasticity of the walls of the central chamber exert excessive pressure on the fluid contained within the central chamber. This pressure exerted by the walls of the central chamber on the fluid contained therein can cause fluid to either leak out of the central chamber, and/or back into a fluid reservoir, which is undesirable. A second recess forming arm of a different shape to the first is then pressed incident on the concave side of the second lens portion to further plastically deform a second portion of the second lens portion outwards. The second recess forming arm may comprise at least two smaller recess forming protrusions. The second set of deformations made to the second lens portion forms the first and second fluid reservoirs. Therefore, the second set of recesses is arranged such that they are formed near the first recess (which forms the central chamber). At least one fluid reservoir includes a pumping mechanism. The pumping mechanism is a pump. The first and second fluid reservoirs and the central chamber may be formed in one formation step, as opposed to two separate formation steps followed by a connections step.

The method further comprises bonding step 212. Bonding step 212 is the step of bonding the second lens portion to the first lens portion, to form a tuneable contact lens. As mentioned earlier in the description, the term “second lens portion” refers to the second lens portion including the central chamber and the first and second fluid reservoirs.

The first lens portion or second lens portion is provided on a compliant stage. The compliant stage may have a greater flexibility than the first and/or second mold parts. The provision of the first lens portion or the second lens portion on the compliant stage can be done manually, or it can be done using an automated machine, such as a robotic device. Optionally, each of the first lens portion and/or second lens portion is provided on a compliant stage.

The compliant stage provided as a support for the first lens portion and/or second lens portion may be of a material that is more pliable than the material of the first mold part and/or second mold part. Using a deformable material to form the compliant stage facilitates ensuring proper alignment and sufficient coupling of the second lens portion to the first lens portion. For example, the contact between the second lens portion and the first lens portion is more complete than when the first lens portion is provided on a rigid convex surface.

The second lens portion is provided on a concave surface. Fluid is then poured into the concave side of the second lens portion such that it sits within the recesses formed in recess forming step 208. Fluid is poured into the first deformed portion such that it is filled. This is the central chamber. The fluid may be a first fluid or a second fluid. A first fluid is also poured into the first fluid reservoir, and a second fluid is poured into the second fluid reservoir. The first fluid and the second fluid are immiscible. This is to ensure that when the contact lens is eventually formed, there are no gas bubbles in either of the fluid reservoirs or the central chamber. In embodiments of the present disclosure, first fluid and second fluid may be poured simultaneously into the first and second fluid reservoirs respectively. Because the fluids are immiscible, as the reservoirs fill and the fluid flows into the central chamber, there will be a boundary formed between the two fluids. This also ensures that there is a similar total amount of each fluid in the contact lens, while ensuring that the central chamber will always be full of fluid.

The first lens portion located on the compliant stage is placed in contact with the second lens portion. The placement of the first lens portion on the second lens portion is such that the second lens portion is aligned with the first lens portion, and the compliant stage/stages provides compression to the second lens portion and/or first lens portion.

Once the second lens portion and the first lens portion are in contact, the methods of the present disclosure then include a step of bonding the second lens portion and the first lens portion to form the tuneable contact lens. The bonding can be achieved using an adhesive, or curing the components together, and the like. This bonding step of the method may include one or more of the following steps:

• Modifying a surface of the first lens portion and or second lens portion, for example prior to bringing the first lens portion and second lens portion into contact;

• Bonding the second lens portion to the first lens portion, for example by heating the second lens portion and the first lens portion while they are in contact;

• Clamping the second lens portion and the first lens portion while they are in contact, for example before bonding;

According to embodiments of the present disclosure, the methods include a step of modifying a surface, e.g. a concave surface, of the second lens portion and/or modifying a surface, e.g. a convex surface, of the first lens portion by exposing the second lens portion and/or the first lens portion respectively to a plasma treatment process. In other words, the surfaces of the second lens portion and first lens portion can be activated by exposing them to plasma.

In the embodiment of Figure 3, the ophthalmic lens is a contact lens. Contact lens 300 is similar in structure to contact lens 100 of Figure la. Central chamber 308 is filled with first fluid 306a, and more specifically, liquid filled region 308a of central chamber 308 is filled with first fluid 306a. Contact lens 300 comprises a pump 358. Pump 358 is located within first fluid reservoir 306.

The pump may be located adjacent the respective fluid reservoir. In such embodiments, the pump may apply external pressure to the fluid reservoir to increase the internal pressure within the fluid reservoir, and therefore force fluid out of the fluid reservoir and into the central chamber. The pump may be located at an outlet of the fluid reservoir. The pumping mechanism may be located at an entrance to the central chamber. The outlet of the fluid reservoir may be in direct fluid communication with the central chamber. The pump may be located within a fluid channel. The fluid channel may be configured to allow fluid communication between the fluid reservoir and the central chamber.

Pump 358 includes a wireless communication module 354. Wireless communication module 354 communicates pump settings 356 to pump 358. There is also provided a control module 350. Control module 350 communicates wirelessly to wireless communication module 354. Control module 350 is configured to receive manual inputs 351 from a wearer of contact lens 300. Control module 350 is external to contact lens 300.

Control module 350 may be comprised in a mobile telephone device. The interface by which a wearer of the ophthalmic lens may provide manual inputs may be a software application on a device. Control module 350 may be comprised in a bespoke device designed to house a control module for tuning an ophthalmic lens.

Control module 350 receives manual inputs 351 from the wearer of contact lens 300, and converts the inputs 351 into an instruction 352. Control module 350 communicates instruction 352 to wireless communication module 354. The instruction comprises an indication of the volume of first fluid 306a to be present in central chamber 308. The indication may be that central chamber 308 is required to be completely filled with first fluid 306a. The indication may be that central chamber 308 is required to contain no volume of first fluid 306a.

The instruction may comprise switching the pump on. The instruction may comprise switching the pump off. The instruction may comprise an “on” instruction, and an “off’ instruction. In embodiments where there is a second pump (not shown) in second fluid reservoir 310, different instructions and settings may be communicated to each pump. For example, first wireless communication module 354 of first pump 358 may receive an instruction comprising an “off’ instruction, and a second wireless communication module of a second pump (provided in second fluid reservoir 310) may receive an instruction comprising an “on” instruction. For example, first wireless communication module 354 of first pump 358 may receive an instruction comprising filling central chamber 308 25% full of first fluid, and a second wireless communication module of a second pump (provided in second fluid reservoir 310) may receive an instruction comprising filling central chamber 308 75% full of second fluid.

Wireless communication module 354 converts instruction 352 to pump setting 356. In the embodiment of Figure 3, pump setting 356 comprises switching pump 358 “on”, such that pump 356 pumps fluid into central chamber 306, and such that central chamber 306 is full of first fluid 306a.

The control module may comprise a plurality of predetermined instructions. The instructions may be pre-calibrated for the prescription of the wearer of the contact lens. The user input may comprise requesting that the contact lens switch between near vision, and distance vision. There may be other distances that the contact lens is configured to switch between. The user input may comprise requesting that the contact lens switch to medium distance vision, or reading vision, for example. The control module may be pre-calibrated to convert these pre-selected user inputs to instructions. The pump may switch between a plurality of pre-calibrated settings.

Each setting may correspond to a distance.

Whilst the present disclosure has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the present disclosure lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

Optionally, the pumping mechanism may be an electro-mechanical actuator. The skilled person would readily appreciate which forms of alternative pumping mechanism would be suitable for the application of the present disclosure.

In example embodiments of the present disclosure, there are more than two fluid reservoirs. In example embodiments, there are two first fluid reservoirs. In example embodiments, there are two second fluid reservoirs. The plurality of fluid reservoirs may be equally spaced around the circumference of the central chamber. The plurality of fluid reservoirs may be positioned such that there is a vertical line of symmetry passing through the centre of the central chamber. There may be two first fluid reservoirs and only one second fluid reservoir for example. In such a situation, the second fluid reservoir may be aligned vertically below the central chamber, and the two first fluid reservoirs may have the same angular deviation from the vertical, relative to a notional vertical line that passes through the centre of the central chamber. The skilled person will readily appreciate that there may be a number of alternatives or variations in the combination or positioning of the fluid reservoirs that are not explicitly described, but fall within the scope of the claims.

Optionally, the central chamber is not circular in plan view, and may be oval, for example.

Optionally, the first and/or second lens portion is not made of silicone elastomer. The first lens portion may be made of any other suitable first lens portion material, such as hydrogel, or rigid gas permeable lenses made from silicone acrylate or variants of such.