Contact lenses and methods thereof

Abstract

A contact lens (100) is provided. The contact lens (100) comprises at least one sensor (101) and processing circuitry (102), the sensor being operable to capture sensor data indicative of a transition of the contact lens between an eye-on state and an eye-off state. The processing circuitry (102) is operable to store information relating to a user of the contact lens (100), detect a transition of the contact lens (100) from an eye-worn state to an off-eye state based on sensor data captured by the at least one sensor (101), and in response to detecting the transition from the eye-worn state to the off-eye state, protect the stored information from unauthorized access. Thereby, if the contact lens (100) is lost or replaced, potential private and / or sensitive information, such as health-related information, is prevented from being unintentionally spread.

Description

Technical Field

[0001] The invention relates to a contact lens, a method performed by a contact lens, a corresponding computer program, a corresponding computer-readable data carrier, and a corresponding data carrier signal. Background Art

[0002] A contact lens (or contact lens for short) is a thin lens that is placed directly on the surface of the eye. A contact lens is an ocular prosthetic device that may be worn to correct vision or for cosmetic or therapeutic reasons.

[0003] Contact lenses can also be equipped with sensors and electronics for health monitoring, for example, for measuring blood oxygen levels and / or pulse rate (see, e.g., US8909311B2). Recently, Mojo Vision and InWith Corporation have developed contact lenses with the ability to visually transmit real-time information to the eyes of a person wearing the contact lenses using a built-in display (see, e.g., https: / / www.mojo.vision / mojo-lens captured on August 19, 2022, https: / / www.cnet.com / science / inwith-promises-worlds-first-smart-contact-lens / captured on August 19, 2022). Such contact lenses are generally referred to as smart contact lenses.

[0004] A problem that arises with different types of advanced contact lenses, including contact lenses for health monitoring, contact lenses incorporating displays, and contact lenses for adaptive vision correction, is that they may store sensitive information, such as measured blood oxygen levels or pulse rates, prescription information, etc. If a user of such contact lenses replaces or loses his / her contact lenses, the sensitive information may become accessible to adversaries who may access the information stored on the lost or replaced contact lenses. Summary of the invention

[0005] It is an object of the present invention to provide an improved alternative to the above-mentioned techniques and prior art.

[0006] More specifically, the object of the present invention is to provide improved solutions for protecting information stored on contact lenses, in particular potentially private or sensitive information stored on contact lenses used for health monitoring, contact lenses including displays, and contact lenses used for adaptive vision correction.

[0007] These and other objects of the invention are achieved by different aspects of the invention as defined in the independent claims. Embodiments of the invention are characterized by the dependent claims.

[0008] According to a first aspect of the present invention, a contact lens is provided. The contact lens comprises at least one sensor and a processing circuit. The at least one sensor is operable to capture sensor data indicating a transition of the contact lens between an on-eye state and an off-eye state. The processing circuit is operable to store information related to a user of the contact lens. The processing circuit is further operable to detect a transition of the contact lens from the on-eye state to the off-eye state. The transition is detected based on the sensor data captured by the at least one sensor. The processing circuit is further operable to protect the stored information from unauthorized access in response to detecting the transition from the on-eye state to the off-eye state.

[0009] According to a second aspect of the present invention, a method is provided. The method is performed by a contact lens. The method includes storing information related to a user of the contact lens. The method further includes detecting a transition of the contact lens from an on-eye state to an off-eye state. The transition is detected based on sensor data captured by at least one sensor included in the contact lens. The at least one sensor is operable to capture sensor data indicating a transition of the contact lens between an on-eye state and an off-eye state. The method further includes protecting the stored information from unauthorized access in response to detecting a transition from the on-eye state to the off-eye state.

[0010] According to a third aspect of the present invention, there is provided a computer program. The computer program comprises instructions, which, when executed by a processor included in a contact lens, causes the contact lens to perform a method according to the second aspect of the present invention, the contact lens comprising at least one sensor operable to capture sensor data indicating a transition of the contact lens between an on-eye state and an off-eye state.

[0011] According to a fourth aspect of the present invention, there is provided a computer readable storage medium having stored thereon a computer program according to the third aspect of the present invention.

[0012] According to a fifth aspect of the present invention there is provided a data carrier signal carrying a computer program according to the third aspect of the present invention.

[0013] The present invention exploits the understanding that potentially private and / or sensitive information stored on a contact lens may be at risk of being disseminated if the contact lens is lost or replaced by its user.To prevent an adversary from gaining access to the stored information, the stored information is protected from unauthorized access.

[0014] Although advantages of the invention have in some cases been described with reference to embodiments of the first aspect of the invention, corresponding reasoning applies to embodiments of the other aspects of the invention.

[0015] Further objectives, features and advantages of the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims.Those skilled in the art realize that different features of the present invention can be combined to create embodiments other than those described in the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and additional objects, features and advantages of the present invention will be better understood through the following illustrative and non-limiting detailed description of embodiments of the present invention with reference to the accompanying drawings, in which:

[0017] Figure 1 A contact lens according to an embodiment of the present invention is schematically illustrated.

[0018] Figure 2 An embodiment of a processing circuit included in a contact lens is schematically illustrated.

[0019] Figure 3 Illustration of a contact lens stored in a trusted environment (left) and a contact lens communicating with a trusted communication device (right).

[0020] Figure 4 A method performed by a contact lens according to an embodiment of the present invention is shown.

[0021] All the figures are schematic, not necessarily to scale, and generally show only parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested. DETAILED DESCRIPTION

[0022] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the present invention are shown. However, the present invention may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided as examples so that this disclosure will be thorough and complete and will fully convey the scope of the present invention to those skilled in the art.

[0023] Figure 1 A contact lens 100 according to an embodiment of the present invention is illustrated. The contact lens 100 may be a soft or rigid (commonly referred to as a hard) contact lens. The contact lens 100 includes at least one sensor 101, which is operable to capture sensor data. The captured sensor data indicates a transition of the contact lens 100 between an eye-wearing state and an eye-off state. In the eye-wearing state, the contact lens 100 is attached to a human eye, specifically, the eye of a user or wearer of the contact lens 100, that is, the contact lens 100 is placed on the surface of the human eye. Correspondingly, in the eye-off state, the contact lens 100 is not attached to the human eye.

[0024] The contact lens 100 further includes processing circuitry 102 . Figure 2 The processing circuit 102 schematically illustrated in FIG. 1 may include: one or more processors 211, such as a central processing unit (CPU), a microprocessor, an application processor, a special purpose processor, a graphics processing unit (GPU), and a digital signal processor (DSP) including an image processor, or a combination thereof; and a memory 212 containing a computer program 213, the computer program 213 containing instructions. When executed by the (one or more) processors 211, these instructions cause the contact lens 100 to become operable according to the embodiments of the present invention described herein. The memory 212 may be, for example, a random access memory (RAM), a read-only memory (ROM), a flash memory, etc. The computer program 213 may be downloaded to the memory 212 as a data carrier signal carrying the computer program 213 through the wireless interface circuit 103. The wireless interface circuit 103 may include one or more of a Bluetooth modem, a near field communication (NFC) circuit, a ZigBee circuit, an optical interface, etc., for receiving and / or transmitting data between the contact lens 100 and one or more communication devices (e.g., a smart phone 320 of a user of the contact lens 100). Processing circuitry 102 may alternatively or additionally include one or more application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or the like, operable to render contact lens 100 operable in accordance with embodiments of the invention described herein.

[0025] The processing circuit 102 may further include one or more interface circuits 201 ( Figure 2 “I / O” in the figure) for communicating with at least one sensor 101, a wireless interface circuit 103, and other circuits optionally included in the contact lens 100.

[0026] More specifically, the processing circuit 102 causes the contact lens 100 to become operable to store information related to a user of the contact lens. Throughout this disclosure, a user of the contact lens 100 is understood to be a person wearing the contact lens 100 in his / her eye. The stored information is typically user-specific information or data. In particular, the stored information may be private and / or sensitive information, such as medical information (related to the user's vision, blood oxygen level, pulse rate, or other health-related information), biometric information (e.g., a pattern or image for iris recognition), user credentials, authentication information, images or information for display on a built-in display, configuration information, etc.

[0027] The contact lens 100 is further operable to detect a transition of the contact lens 100 from an on-eye state to an off-eye state. In other words, the contact lens 100 is no longer attached to the eye, but has become detached. This may be the case if a user of the contact lens 100 has (intentionally) removed the contact lens 100 from his / her eye, or the contact lens 100 has inadvertently become detached from the user's eye, i.e., it has been lost. The transition of the contact lens 100 from the on-eye state to the off-eye state is detected based on sensor data captured by the at least one sensor 101, as described in further detail below.

[0028] The contact lens 100 is further operable to protect the stored information from unauthorized access. More specifically, in response to detecting a transition of the contact lens 100 from the on-eye state to the off-eye state, the stored information is protected from unauthorized access. Thus, the risk of disseminating the information stored on the contact lens 100 is mitigated or at least reduced.

[0029] Optionally, the contact lens 100 is further operable to start a timer in response to detecting a transition from the wearing state to the off-eye state, and after the timer expires, the stored information is protected from unauthorized access. Thus, the user of the contact lens 100 is given the opportunity to put the contact lens 100 back into his / her eyes before protecting the information from unauthorized access. The timer can be configured with a sufficiently long duration to allow a user who has lost his / her contact lens 100 to find the contact lens 100 and put it back into his / her eyes. It will be appreciated that the duration of the timer should not be too long to reduce the risk of an adversary finding the lost contact lens 100 and obtaining access to the information stored on the contact lens 100. For example, the duration of the timer can be set to a duration between 30 seconds and several minutes. It is also conceivable that the duration of the timer can be set to a duration that depends on one or more of the time of day, place or location, whether the contact lens 100 is located indoors or outdoors, etc.

[0030] Preferably, the contact lens 100 is further operable to stop the timer in response to detecting any of the following: a transition of the contact lens 100 from an off-eye state to an on-eye state, proximity of a trusted environment, and communication between the contact lens 100 and a trusted communication device. Stopping the timer before the timer has expired means that the stored information is not protected from unauthorized access.

[0031] In practice, the transition of the contact lens 100 from the off-eye state to the on-eye state means that the contact lens 100 is attached to the human eye again. Optionally, the timer is stopped only when the contact lens 100 has identified the eye as the eye of its user or the eye to which the contact lens 100 was attached before it became off-eye. For example, this can be achieved by providing the contact lens 100 with an iris scanning capability for biometric identification of the eye, as disclosed in, for example, US8798332B2.

[0032] The trusted environment may be, for example, a lens case 310 in which the contact lens 100 is stored when not in use, such as Figure 3 . A lens case is typically used to store contact lenses when they are not in use (e.g., during the night). Detecting the proximity of a trusted environment such as a lens case 310 may be based, for example, on the contact lens (using its wireless interface circuit 103) detecting a radio signal transmitted or broadcast by the lens case 310 (e.g., via NFC). Alternatively, the lens case 310 may be equipped with a QR code or other preferably unique visual pattern that can be captured by a camera included in the contact lens 100. As a further alternative, the contact lens 100 may detect visible or infrared coded light emitted inside the lens case 310 by either an optical sensor (which may be part of the wireless interface circuit 103) or a camera equipped with the contact lens 100. In this context, when the contact lens 100 is not attached to the user's eye, the proximity of the contact lens 100 to a trusted environment (such as a lens case 310) is considered an indication that the contact lens 100 is under the control of its user and no longer requires protection of stored information from unauthorized access.

[0033] The trusted communication device may be, for example, a smartphone 320 or any other computing or communication device of the user. By placing the contact lens 100 in proximity to the trusted communication device (such as the smartphone 320), wireless communication may be initiated between the contact lens 100 (via its wireless interface circuit 103) and the corresponding wireless interface of the smartphone 320. In practice, this may be used to update the configuration and / or software of the contact lens 100, to provide information to the contact lens 100 for display to the user on a built-in display of the contact lens 100, or to retrieve and / or transmit medical or health-related information from and / or to the contact lens 100, such as measured blood oxygen levels or pulse rates, or eye prescription data. The established wireless communication may also be used to recover information that has been erased (as part of protecting stored information from unauthorized access), to recover tokens or credentials required to access a memory storing the information, and so forth, as described in further detail below. The trusted communication device may also be implemented as a lens box 320 , for example, if the user's smartphone is not equipped with a compatible wireless interface to communicate with the wireless interface circuit 103 of the contact lens 100 , the lens box 320 may act as a gateway or intermediate node for establishing wireless communication with the contact lens 100 .

[0034] In the following, different alternatives for protecting stored information from unauthorized access are described in more detail. In the present context, stored information is understood as potentially private and / or sensitive information stored in a data storage device included in the contact lens 100, such as the memory 212 or any separate memory.

[0035] For example, the contact lens 100 may be operable to protect the stored information from unauthorized access by erasing the stored information. As an example, if the information is stored in a volatile memory, the memory or portion thereof storing the information may be powered off for a short period of time sufficient to erase the memory. Alternatively, particularly if the memory is of a non-volatile type, those portions of the memory storing the information may be overwritten.

[0036] As another example, the contact lens 100 may be operable to protect stored information from unauthorized access by encrypting the stored information. When attached to the eye of its user, i.e., when in the eye-wearing state, there is no need to constantly encrypt and decrypt the information when accessing the stored information (for either reading or writing), as this consumes power and processing resources that are typically scarce in a (smart) contact lens. Instead, the stored information is encrypted only when the contact lens 100 leaves its eye-wearing state.

[0037] As yet another example, the contact lens 100 may be operable to protect stored information from unauthorized access by resetting a memory storing the information (such as the memory 212 or any separate memory) to a default state. In practice, this may correspond to a factory reset, i.e., the configuration of the contact lens 100 is restored to its factory state before it is configured for a particular user and / or user-specific information or data (such as eye prescription information) has been stored on the contact lens 100. Resetting the memory to its default state may include erasing the information stored in the memory 212, as well as resetting the configuration information to the default state.

[0038] As yet another example, the contact lens 100 may be operable to protect stored information from unauthorized access by limiting access to a memory (such as the memory 212 or any separate memory or portion thereof) in which the information is stored. For example, if the information is stored in the memory 212, a memory controller (which may be part of the memory 212 or separate) may require a token or credential in order to grant access to the memory 212 or a portion thereof (e.g., a protected area of ​​the memory 212) in which the information is stored. In practice, the stored information may be protected by erasing the token or credential.

[0039] As another example, the contact lens 100 may be operable to protect the stored information from unauthorized access in response to detecting that the remaining energy of the power supply 104 included in the contact lens is less than a threshold value. The power supply 104 may be, for example, a battery or a capacitor, and may alternatively or additionally be based on obtaining energy from motion, light, or radio frequency radiation. Alternatively, the power supply 104 may also be an aqueous battery based on tears (see, for example, J. Yun et al., "Tear-Based Aqueous Batteries for Smart Contact Lenses Enabled by Prussian Blue Analogue Nanocomposites", NanoLett., Vol. 21, pp. 1659-1665, American Chemical Society, 2021, https: / / doi.org / 10.1021 / acs.nanolett.0c04362). The threshold value may be equal to or greater than the amount of energy required to protect the stored information from unauthorized access. That is, the threshold value is configured so that the remaining energy is sufficient to perform one or more of the measures described above for protecting the stored information from unauthorized access. Thus, even in the event that the built-in power source 104 is depleted to a residual energy level insufficient to protect the stored information when the contact lens 100 is lost (ie, becomes disengaged from the eye), the stored information is protected from unauthorized access.

[0040] The contact lens 100 may further include a visual indicator 105, and the contact lens 100 may further be operable to activate the visual indicator 105 in response to detecting a transition from the on-eye state to the off-eye state. The visual indicator 105 may be, for example, a light emitting diode (LED) or a display, which may be activated in response to detecting a transition from the on-eye state to the off-eye state. Thus, the user may be informed that stored information is about to be protected, possibly erasing information stored on the contact lens 100. For example, if the contact lens 100 has fallen to the floor, the visual indicator 105 (such as a flashing light) may also facilitate the user to find the contact lens 100. Optionally, the contact lens 100 may be operable to deactivate, disable or turn off the visual indicator 105 in response to detecting any of the following: a transition from the off-eye state to the on-eye state, proximity of a trusted environment (such as a lens case 310), and communication between the contact lens and a trusted communication device (such as a user's smart phone 320), similar to what has been described above. Preferably, the contact lens 100 may be operable to deactivate the visual indicator 105 only after it has identified the eye as the eye of its user or the contact lens 100 becomes the eye to which it was attached before being detached from the eye. This may be achieved, for example, by providing the contact lens 100 with an iris scanning capability for biometric identification of the eye, as disclosed in US8798332B2. If the contact lens is attached to a different eye, particularly the eye of an authorized user or the eye of a person other than the user, the visual indicator may be activated or maintained in an active state to indicate to the person wearing the contact lens 100 that he / she is not the legitimate user of the contact lens 100, and / or that the information stored on the contact lens 100 is still protected from unauthorized access.

[0041] The contact lens 100 may further be operable to restore the protected information in response to detecting any of the following: a transition of the contact lens from an off-eye state to an on-eye state, proximity of a trusted environment (such as a lens case 310), and communication between the contact lens and a trusted communication device (such as a user's smartphone 320). For example, if the stored information has been erased or reset to a default state, the contact lens 100 may be restored by receiving a message from a trusted communication device (such as a user's smartphone 320). Figure 3Alternatively, if the stored information has been encrypted, the information may be restored by decrypting the encrypted information. This may be accomplished, for example, by retrieving an encryption key required to decrypt the information from a trusted communication device (e.g., smart phone 320). As a further alternative, if the stored information is protected by locking the information, such as by requiring a token or credential to access the stored information that is erased in response to detecting a transition from the on-eye state to the off-eye state, the information may be restored by recovering the token or credential. For example, the token or credential may be received from a trusted communication device such as smart phone 320.

[0042] In the following, different alternatives for detecting the transition of the contact lens 100 from the on-eye state to the off-eye state are described.

[0043] For example, at least one sensor 101 may include a shape sensor, and the contact lens 100 may be operable to detect a transition from the on-eye state to the off-eye state by detecting a change in the shape of the contact lens 100 indicating that the contact lens 100 is detached from the eye. The shape sensor 101 may be a stress or strain sensor, or any other sensor capable of detecting a change in the shape of the contact lens 100. This is based on the understanding that the shape of the contact lens 100 when attached to the eye (i.e., when in its on-eye state) adapts to the shape of the eyeball. The shape of the contact lens 100 in its on-eye state is different from its shape in its off-eye state (i.e., when it is not attached to the eye). If the captured sensor data indicates that the shape change exceeds a threshold, the contact lens 100 determines that a transition of the contact lens 100 from the on-eye state to the off-eye state has occurred.

[0044] As an alternative, at least one sensor 101 may include a motion sensor, and the contact lens 100 may be operable to detect a transition from the on-eye state to the off-eye state by detecting a characteristic motion of the contact lens 100. The motion sensor 101 may, for example, include an accelerometer, a geomagnetic field sensor, etc. When attached to the eye, the movement of the contact lens 100 follows the characteristic motion of the eye. Typically, these are angular motions within a limited angular range (excluding any translational motion of the head). In contrast, when the contact lens 100 is detached from the eye, for example, when it falls to the ground, its motion is characterized by a translational motion with an acceleration substantially equal to the acceleration of gravity. Alternatively, this may be detected based on a motion pattern indicating that the detached lens is in free fall. In practice, a transition from the on-eye state to the off-eye state may be detected using either a set of thresholds and rules or a machine learning model, which is trained to classify sensor data from the motion sensor 101 into motions specific to the on-eye state and motions specific to the transition from the on-eye state to the off-eye state, and / or motions specific to the lens in free fall.

[0045] As a further alternative, at least one sensor 101 may include a thermometer arranged to measure the temperature at the concave surface of the contact lens 100. The thermometer 101 may, for example, be disposed on or near the concave surface of the contact lens 100 adjacent to the eye (also referred to as the rear lens area). The contact lens 100 is operable to detect a transition from the on-eye state to the off-eye state by detecting a change in temperature at the concave surface of the contact lens 100. When attached to the eye, the temperature measured at the concave surface of the contact lens 100 is substantially constant and is determined by the temperature of the eye to which the contact lens 100 is attached. When detached from the eye, the temperature fluctuates to a greater extent than in the on-eye state and reflects the (air) temperature of the environment. Detecting the transition from the on-eye state to the off-eye state may be based on the measured temperature change exceeding a threshold value. The contact lens 100 may optionally include a second thermometer arranged to measure the temperature at the convex surface of the lens, which is the face that does not face the eye when the contact lens is attached to the eye (also referred to as the front lens area). When the contact lens 100 is in its on-eye state, the temperatures measured by the two thermometers are usually different, and the temperature measured by the concave thermometer (adjacent to the eye) is usually more stable. On the other hand, in the off-eye state, the temperature readings from the two thermometers are substantially equal because they both measure the same (air) temperature.

[0046] As a further alternative, at least one sensor 101 may include a conductivity sensor arranged to measure the conductivity at the concave surface of the contact lens 100. The conductivity sensor 101 may, for example, be disposed on or near the concave surface of the contact lens 100 adjacent to the eye (the region behind the lens). The contact lens 100 may be operable to detect a transition from an on-eye state to an off-eye state by detecting a change in conductivity at the concave surface of the contact lens 100. Because the saline fluid wets the outer surface of the eye (also known as the tear film), the presence of the eye to which the contact lens 100 is attached affects the conductivity measured at the concave surface of the contact lens 100. Therefore, when the contact lens 100 is separated from the eye, the conductivity is expected to change. The detection of the transition from the on-eye state to the off-eye state may, for example, be based on a change in conductivity exceeding a threshold value.

[0047] As a further alternative, at least one sensor 101 may include a humidity sensor arranged to measure the humidity at the concave surface of the contact lens 100. The humidity sensor 101 may, for example, be disposed on or near the concave surface of the contact lens 100 adjacent to the eye (the region behind the lens). The contact lens 100 may be operable to detect a transition from the on-eye state to the off-eye state by detecting a change in humidity at the concave surface of the contact lens 100. Similar to embodiments of the contact lens 100 that rely on a change in conductivity to detect a transition from the on-eye state to the off-eye state, the presence of fluid (tear film) that wets the eye to which the contact lens 100 is attached affects the humidity at the concave surface of the contact lens 100 (adjacent to the eye). Therefore, when the contact lens 100 is separated from the eye, it is expected that the humidity will change. The detection of the transition from the on-eye state to the off-eye state may, for example, be based on a change in humidity exceeding a threshold.

[0048] As a further alternative, at least one sensor 101 may include a pulse sensor, and the contact lens 100 may be operable to detect a transition from the on-eye state to the off-eye state in response to the pulse sensor 101 ceasing to detect a pulse during a threshold duration. The pulse sensor 101 may be, for example, a pulse oximeter as disclosed in US8909311B2. When the contact lens 100 becomes detached from the eye, the pulse sensor 101 stops detecting the pulse, which indicates a transition of the contact lens 100 from the on-eye state to the off-eye state. Since a normal heart rate of a person at rest is between 60 and 100 beats per minute, the threshold may be set between two seconds and several seconds.

[0049] As a further alternative, at least one sensor 101 may comprise a pressure sensor arranged to measure the pressure at the concave surface of the contact lens 100. The pressure sensor 101 may be disposed, for example, on or near the concave surface of the contact lens 100 adjacent to the eye (the region behind the lens). The contact lens 100 may be operable to detect the transition from the on-eye state to the off-eye state by detecting a pressure change at the concave surface of the contact lens 100, which pressure change is comparable to the surface tension to which the contact lens 100 is subjected when in the on-eye state. The detection of the transition from the on-eye state to the off-eye state may be based, for example, on the surface tension change exceeding a threshold value. In practice, when the contact lens 100 becomes detached from the eye, the measured pressure value is expected to drop to substantially zero.

[0050] As a further alternative, at least one sensor 101 may include a blink sensor, and the contact lens 100 may be operable to detect a transition from the on-eye state to the off-eye state in response to the blink sensor 101 ceasing to detect blinks during a threshold duration. On average, humans blink 15 to 20 times per minute. This means that if a blink has not been detected for a duration of, for example, 10 seconds, this is an indication that the contact lens is no longer attached to the eye. In this context, blinking is understood as the closing of the eyelid from an open state to a substantially closed state for a short period of time, after which the eyelid returns to an open state for a relatively longer period of time than the closed state. The blink sensor 101 may, for example, be based on an optical sensor that detects changes in light intensity when blocked by a closed eyelid.

[0051] In the following, reference Figure 4 An embodiment of a method 400 performed by a contact lens 100 is described. The method 400 includes storing 401 information related to a user of the contact lens 100. The method 400 further includes detecting 402 a transition of the contact lens 100 from an on-eye state to an off-eye state. The transition is detected based on sensor data captured by at least one sensor 101 included in the contact lens 100. The at least one sensor 101 is operable to capture sensor data indicating a transition of the contact lens 100 between the on-eye state and the off-eye state. The method 400 further includes protecting 406 the stored information from unauthorized access. In response to detecting the transition from the on-eye state to the off-eye state, the stored information is protected.

[0052] The method 400 may further include starting 404 a timer in response to detecting a transition from the on-eye state to the off-eye state, and after the timer expires, protecting 406 the stored information from unauthorized access. Optionally, the method 400 may further include stopping 405 the timer in response to detecting any of the following: a transition of the contact lens 100 from the off-eye state to the on-eye state, proximity of a trusted environment (such as a lens case 310), and communication between the contact lens and a trusted communication device (such as a smart phone 320).

[0053] The stored information can be protected from unauthorized access by erasing the stored information.

[0054] Alternatively, the stored information may be protected from unauthorized access by encrypting the stored information.

[0055] Alternatively, the stored information may be protected from unauthorized access by resetting the memory 212 storing the information to a default state.

[0056] Alternatively, the stored information may be protected from unauthorized access by limiting access to the memory 212 where the information is stored.

[0057] The method 400 may further include protecting 406 the stored information from unauthorized access in response to detecting that the remaining energy of the power source 104 included in the contact lens 100 is less than a threshold value.

[0058] The method 400 may further include activating 403 a visual indicator 105 included in the contact lens 100 in response to detecting the transition from the on-eye state to the off-eye state.

[0059] The method 400 may further include restoring 407 the protected information in response to detecting any of the following: a transition of the contact lens 100 from an off-eye state to an on-eye state, proximity of a trusted environment (such as a lens case 310), and communication between the contact lens and a trusted communication device (such as a smart phone 320).

[0060] The at least one sensor 101 may include a shape sensor, and detect a transition from the on-eye state to the off-eye state by detecting a change in the shape of the contact lens 100 indicating that the contact lens 100 is detached from the eye.

[0061] The at least one sensor 101 may include a motion sensor, and detects the transition from the on-eye state to the off-eye state by detecting a characteristic motion of the contact lens 100 .

[0062] The at least one sensor 101 may include a thermometer arranged to measure the temperature at the concave surface of the contact lens 100 , and detect the transition from the on-eye state to the off-eye state by detecting the temperature change at the concave surface of the contact lens 100 .

[0063] At least one sensor 101 may include a conductivity sensor arranged to measure conductivity at a concave surface of the contact lens 100 , and detect a transition from an on-eye state to an off-eye state by detecting a conductivity change at the concave surface of the contact lens 100 .

[0064] At least one sensor 100 may include a humidity sensor arranged to measure humidity at a concave surface of the contact lens 100 , and detect a transition from an on-eye state to an off-eye state by detecting a change in humidity at the concave surface of the contact lens 100 .

[0065] The at least one sensor 101 may include a pulse sensor, and detect the transition from the on-eyes state to the off-eyes state in response to the pulse sensor ceasing to detect a pulse during a threshold duration.

[0066] At least one sensor 101 may include a pressure sensor, which is arranged to measure the pressure at the concave surface of the contact lens 100, and detect the transition from the on-eye state to the off-eye state by detecting the pressure change at the concave surface of the contact lens 100, which is equivalent to the surface tension to which the contact lens 100 is subjected in the on-eye state.

[0067] The at least one sensor 101 may include a blink sensor, and detect a transition from the on-eyes state to the off-eyes state in response to the blink sensor ceasing to detect blinks during a threshold duration.

[0068] It will be appreciated that the method 400 may include additional, alternative or modified steps in accordance with what is described throughout this disclosure. An embodiment of the method 400 may be implemented as a computer program 213 including instructions that, when executed by a processor 211 included in a contact lens 100, cause the contact lens 100 to perform the method 400 and become operable in accordance with embodiments of the invention described herein, the contact lens 100 including at least one sensor 101 operable to capture sensor data indicative of a transition of the contact lens 100 between an on-eye state and an off-eye state. The computer program 213 may be stored in a computer-readable data carrier such as the memory 212. Alternatively, the computer program 213 may be carried by a data carrier signal, for example, downloaded to the memory 212 via the wireless interface circuit 103.

[0069] Those skilled in the art realize that the present invention is by no means limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Claims

1. A contact lens (100), comprising: at least one sensor (101) operable to capture sensor data indicative of a transition of the contact lens (100) between an on-eye state and an off-eye state; as well as A processing circuit (102) operable to: storing information related to a user of the contact lens (100), detecting a transition of the contact lens (100) from the on-eye state to the off-eye state based on sensor data captured by the at least one sensor (101), and In response to detecting the transition from the on-eyes state to the off-eyes state, the stored information is protected from unauthorized access.

2. The contact lens (100) of claim 1, wherein the processing circuit (102) is further operable to: In response to detecting the transition from the on-eyes state to the off-eyes state, a timer is started, and after expiration of the timer, the stored information is protected from unauthorized access.

3. The contact lens (100) according to claim 2, the processing circuit (102) is further operable to stop the timer in response to detecting any of the following: a transition of the contact lens (100) from the off-eye state to the on-eye state, an approach of a trusted environment (310), and communication between the contact lens (100) and a trusted communication device (320).

4. The contact lens (100) of any one of claims 1 to 3, the processing circuit (102) being operable to protect the stored information from unauthorized access by erasing the stored information.

5. The contact lens (100) of any one of claims 1 to 3, the processing circuit (102) being operable to protect the stored information from unauthorized access by encrypting the stored information.

6. The contact lens (100) of any one of claims 1 to 3, the processing circuit (102) being operable to protect the stored information from unauthorized access by resetting the memory (212) storing the information to a default state.

7. The contact lens (100) of any one of claims 1 to 3, the processing circuit (102) being operable to protect the stored information from unauthorized access by limiting access to a memory (212) storing the information.

8. According to any one of claims 1 to 7, the processing circuit (102) is further operable to protect the stored information from unauthorized access in response to detecting that the remaining energy of a power supply (104) included in the contact lens (100) is less than a threshold.

9. The contact lens (100) according to any one of claims 1 to 8, further comprising a visual indicator (105), and the processing circuit (102) is further operable to activate the visual indicator (105) in response to detecting the transition from the on-eye state to the off-eye state.

10. The contact lens (100) according to any one of claims 1 to 9, wherein the processing circuit (102) is further operable to restore protected information in response to detecting any one of the following: a transition of the contact lens (100) from the off-eye state to the on-eye state, an approach of a trusted environment (310), and communication between the contact lens (100) and a trusted communication device (320).

11. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) includes a shape sensor, and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state by detecting a change in shape of the contact lens (100) indicating that the contact lens (100) is detached from the eye.

12. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) comprises a motion sensor, and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state by detecting a characteristic movement of the contact lens (100).

13. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) comprises a thermometer, which is arranged to measure the temperature at the concave surface of the contact lens (100), and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state by detecting the temperature change at the concave surface of the contact lens (100).

14. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) comprises a conductivity sensor, which is arranged to measure the conductivity at the concave surface of the contact lens (100), and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state by detecting a change in the conductivity at the concave surface of the contact lens (100).

15. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) includes a humidity sensor, which is arranged to measure the humidity at the concave surface of the contact lens (100), and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state by detecting the change in humidity at the concave surface of the contact lens (100).

16. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) includes a pulse sensor, and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state in response to the pulse sensor (101) ceasing to detect a pulse during a threshold duration.

17. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) comprises a pressure sensor, which is arranged to measure the pressure at the concave surface of the contact lens (100), and the processing circuit (102) is operable to detect the transition from the on-eye state to the off-eye state by detecting a pressure change at the concave surface of the contact lens (100), wherein the pressure change is equivalent to the surface tension to which the contact lens (100) is subjected in the on-eye state.

18. The contact lens (100) according to any one of claims 1 to 10, wherein: The at least one sensor (101) includes a blink sensor, and the processing circuit (102) is operable to detect the transition from the on-eyes state to the off-eyes state in response to the blink sensor (101) ceasing to detect blinks during a threshold duration.

19. A method (400) performed by a contact lens (100), the method comprising: storing (401) information related to a user of the contact lens (100), detecting (402) a transition of the contact lens (100) from an on-eye state to an off-eye state based on sensor data captured by at least one sensor (101) included in the contact lens (100), the at least one sensor (101) being operable to capture sensor data indicative of the transition of the contact lens (100) between the on-eye state and the off-eye state, and In response to detecting (402) the transition from the on-eyes state to the off-eyes state, the stored information is protected (406) from unauthorized access.

20. The method (400) of claim 19, further comprising: In response to detecting (402) the transition from the on-eyes state to the off-eyes state, a timer is started, and after expiration of the timer, the stored information is protected (406) from unauthorized access.

21. The method (400) of claim 20, further comprising stopping (405) the timer in response to detecting any of the following: a transition of the contact lens from the off-eye state to the on-eye state, proximity of a trusted environment, and communication between the contact lens and a trusted communication device.

22. The method (400) according to any one of claims 19 to 21, wherein: The stored information is protected from unauthorized access by erasing the stored information.

23. The method (400) according to any one of claims 19 to 21, wherein: The stored information is protected from unauthorized access by encrypting the stored information.

24. The method (400) according to any one of claims 19 to 21, wherein: The stored information is protected from unauthorized access by resetting the memory (212) storing the information to a default state.

25. The method (400) according to any one of claims 19 to 21, wherein: The stored information is protected from unauthorized access by limiting access to a memory (212) storing the information.

26. The method (400) according to any one of claims 19 to 25, further comprising: In response to detecting that the remaining energy of a power source (104) included in the contact lens (100) is less than a threshold, protecting (406) the stored information from unauthorized access.

27. The method (400) according to any one of claims 19 to 26, further comprising: In response to detecting (402) the transition from the on-eye state to the off-eye state, a visual indicator (105) included in the contact lens (100) is activated (403).

28. The method (400) according to any one of claims 19 to 27, further comprising restoring (407) protected information in response to detecting any one of the following: a transition of the contact lens (100) from the off-eye state to the on-eye state, proximity of a trusted environment (310), and communication between the contact lens and a trusted communication device (320).

29. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) comprises a shape sensor, and detects the transition from the on-eye state to the off-eye state by detecting a change in the shape of the contact lens (100) indicating that the contact lens (100) is detached from the eye.

30. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) comprises a motion sensor and detects the transition from the on-eye state to the off-eye state by detecting a characteristic movement of the contact lens (100).

31. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) comprises a thermometer, which is arranged to measure the temperature at the concave surface of the contact lens (100), and detects the transition from the on-eye state to the off-eye state by detecting the temperature change at the concave surface of the contact lens (100).

32. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) comprises a conductivity sensor, which is arranged to measure the conductivity at the concave surface of the contact lens (100), and detect the transition from the on-eye state to the off-eye state by detecting a change in the conductivity at the concave surface of the contact lens (100).

33. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) comprises a humidity sensor, which is arranged to measure the humidity at the concave surface of the contact lens (100), and detect the transition from the on-eye state to the off-eye state by detecting the humidity change at the concave surface of the contact lens (100).

34. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) includes a pulse sensor, and the transition from the on-eyes state to the off-eyes state is detected in response to the pulse sensor (101) ceasing to detect a pulse during a threshold duration.

35. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) comprises a pressure sensor, which is arranged to measure the pressure at the concave surface of the contact lens (100), and detects the transition from the on-eye state to the off-eye state by detecting the pressure change at the concave surface of the contact lens (100), wherein the pressure change is equivalent to the surface tension to which the contact lens (100) is subjected in the on-eye state.

36. The method (400) according to any one of claims 19 to 28, wherein: The at least one sensor (101) includes a blink sensor, and the transition from the on-eyes state to the off-eyes state is detected in response to the blink sensor (101) ceasing to detect blinks during a threshold duration.

37. A computer program (213) comprising instructions, when the computer program (213) is executed by a processor (211) included in a contact lens (100), the computer program causes the contact lens (100) to implement the method (400) according to any one of claims 19 to 36, the contact lens (100) comprising at least one sensor (101), the at least one sensor (101) being operable to capture sensor data indicating a transition of the contact lens (100) between an on-eye state and an off-eye state.

38. A computer-readable data carrier (212) having stored thereon a computer program (213) according to claim 37.

39. A data carrier signal, the data carrier signal carrying A computer program (213) as claimed in claim 37.

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