Instrumented contact lens and associated device for measuring refractive error and / or accommodation.

Abstract

Instrumented contact lens and associated device for measuring refractive error and / or accommodation.The invention relates to a contact lens (1) intended to be worn by an eye of the individual, for measuring refractive error and / or accommodation of the eye, comprising: - a membrane (10) adapted to transparently cover the pupil and to cover the iris of the eye and preferably at least partially the sclera; - at least one illumination source (11, 12) encapsulated in the membrane, the illumination source(s) being adapted to emit two cones or light beams (F1, F2) whose divergence is controlled relative to the axis of the lens, one of the two beams being intended to be directed towards the inside of the membrane towards the crystalline lens and / or the retina of the eye so as to create a source point on the latter, while the other of the two beams is intended to be directed towards the outside of the membrane in a direction away from the eye. Figure for abstract: Fig. 1.

Description

Title of the invention: Instrumented contact lens and associated device for measuring refractive error and / or accommodation. Technical field

[0001] The present invention relates to an instrumented contact lens and also to an associated autorefractometer.

[0002] The lens according to the invention can be a completely autonomous system and installed on at least one eye of an individual.

[0003] The invention aims in particular to automatically measure the refractive error of an individual. Prior art

[0004] An autorefractometer is a device that allows a patient to be measured non-invasively and objectively in terms of their vision correction, also known as refractive error. This measurement is generally used as a starting point for prescribing glasses or contact lenses.

[0005] Existing ones can be classified into two main categories: conventional auto-refractometers and aberrometers.

[0006] The first ones only allow the measurement of lower order aberrations (sphere, cylinder and axis) while the aberrometers measure the so-called low order and high order (spherical aberration, coma, trefoil, etc.).

[0007] A second difference is that conventional autorefractometers measure the power of the eye generally on a region of the pupil, which is small and central, compared to that measured by aberrometers.

[0008] Autorefractometers typically use an infrared source directed at the retina. The measurement of refractive error is based on one or more measurements of the light reflected by the retina. For example, if the source emits a cone of light, the autorefractometer can determine when a patient's eye is correctly focusing the light based on the size and shape of the ring on the retina. The instrument changes the vergence until the image is sharp. The process is repeated in at least three meridians of the eye and the autorefractometer calculates the refraction of the eye, the sphere, the cylinder and the axis. The measurement can also be based on contrast optimization, or the so-called Scheiner principle, beam deflection, etc.

[0009] In the case of an aberrometer, a source point is formed on the retina, and the reflected wavefront is analyzed by an analyzer, most often of the Shack-Hartman type (English acronym SHWFS for “Shack-Hartmann Wave Front Sensor”).

[0010] The instruments formed by conventional auto-refractometers integrate, most of the time, a chin rest and always a fixation target.

[0011] In a number of cases, it would be desirable for this measurement to be done automatically without it being carried out by a visual health professional, such as an ophthalmologist. For example, wearing glasses can hinder the use of many modern devices (rifle scopes, microscopes, augmented reality glasses, virtual reality headsets, etc.). An automatic measurement of the refractive error would make it possible to correct it automatically without being constrained by modern devices, for example when the user wears a rifle scope to his eyes, uses a microscope objective, etc. This would also make it possible to consider the measurement of the refractive error as an outpatient test.

[0012] Thus, if one of these devices incorporated an auto-refractometer, its optics could be automatically adjusted to the eyesight of each individual, thus allowing them to have a perfect image without the said individual being obliged to wear corrective glasses.

[0013] A difficulty with this integration is that the quality of the measurement depends on good control of the alignment of the individual's visual axis with the auto-refractometer limiting its mobility.

[0014] There is therefore a need to further improve existing auto-refractometers, in particular to enable their integration with modern equipment (scope, microscope, augmented reality glasses, virtual reality headset, etc.), while ensuring good control of the alignment of the visual axis with an individual wearing the equipment and without this hindering the mobility of the latter, and preferably in possibly ambulatory use.

[0015] The aim of the invention is to at least partially meet this need. Statement of the invention

[0016] To do this, the invention relates to a contact lens intended to be worn by an individual's eye, for measuring refractive error and / or accommodation of the eye, comprising:

[0017] - a membrane adapted to transparently cover the pupil and to cover the iris of the eye and preferably at least partially the sclera;

[0018] - at least one illumination source encapsulated in the membrane, the source(s) illumination being adapted to emit two cones or light beams whose divergence is controlled relative to the axis of the lens, one of the two beams being intended to be directed towards the inside of the membrane in the direction of the lens and / or the retina of the eye so as to create a source point on the latter, while the other of the two beams is intended to be directed towards the outside of the membrane in a direction away from the eye.

[0019] According to an advantageous embodiment, the contact lens comprises at least two separate illumination sources, one of which emits the beam intended to be directed towards the inside of the membrane in the direction of the lens and / or the retina of the eye and the other emits the beam intended to be directed towards the outside of the membrane in a direction away from the eye.

[0020] According to another advantageous embodiment, the contact lens comprises at least one optical diffraction element, encapsulated in the membrane and configured to receive the light beam emitted by the illumination source(s) directed towards the inside of the membrane and to diffract said beam towards the lens and / or the retina of the eye and create at least two distinct source points on the retina so as to produce interference between the beams reflected by the retina.

[0021] According to another advantageous embodiment, the contact lens comprises at least one other optical diffraction element, encapsulated in the membrane and configured to receive the light beam emitted by the illumination source(s) directed towards the outside of the membrane and to collimate said beam or project a target or a sight, such as a grid so as to allow the calculation of the orientation of the gaze, such as cyclo-torsions, or the addressing of one or more detectors arranged on the periphery of the eye.

[0022] Preferably, the illumination sources emit in the infrared.

[0023] According to an advantageous variant, the illumination source(s) is(are) one or more light-emitting diodes (LEDs) or one or more vertical cavity surface-emitting lasers (VCSELs) or one or more edge-emitting laser diodes. According to this variant, the LED or VCSEL diode(s) is(are) advantageously provided with an optic for shaping its(their) beam.

[0024] According to an advantageous embodiment, the contact lens comprises:

[0025] - at least one interface for collecting and supplying electrical energy to the illumination sources, from outside the lens;

[0026] - at least one electronic circuit adapted to activate the sources from the interface.

[0027] According to this mode and an advantageous variant embodiment, the contact lens comprises a battery encapsulated in the membrane and connected to the interface, the battery being adapted to be recharged from the interface and to electrically power the illumination sources and / or the optoelectronic functions associated with the illumination sources, the electronic circuit being adapted to activate the sources from the battery.

[0028] According to an advantageous embodiment variant, the interface comprises an antenna adapted for the transfer of energy by electromagnetic induction, and a rectifier connected to the antenna to transfer all or part of the energy received by the antenna to the sources, and where appropriate to the battery and / or other optoelectronic functions encapsulated in the membrane. Remote energy transfer by induction, particularly for the purpose of recharging the battery, is advantageous because it can be done easily and quickly without an external connection, by means of an antenna integrated into the support (glasses frame, augmented reality headset) that will be used for the detection of beams from the illumination sources.

[0029] Preferably, the rectifier is adapted to transfer all or part of the energy received by induction directly to the illumination sources.

[0030] According to an advantageous variant, the antenna can be adapted for wireless data transmission, in particular by radio frequencies (RF).

[0031] Advantageously, at least one of the two illumination sources is implemented as part of a communication system.

[0032] Advantageously, the battery is a deformable accumulator, encapsulated in the membrane. It may be an accumulator described and claimed in patent application WO2018 / 167393 A1. Such an accumulator has the advantage of being of very small dimensions, typically with a surface area of ​​the order of 0.75cm2. This flexible battery also has the advantageous characteristics of being stretchable and self-repairing so as to be best integrated into the contact lens and to be able to ensure sufficient autonomy for the operation of the illumination sources.

[0033] The contact lens is preferably a rigid or hybrid (semi-rigid) scleral lens. A scleral lens has the advantage of being more stable on the eye than a conventional contact lens, which is advantageous for such an eye-mounted device. A scleral lens offers a larger useful surface area.

[0034] The invention also relates to an auto-refractometer comprising:

[0035] - at least one contact lens as described above;

[0036] - a support, intended to be positioned in a fixed manner relative to the face of the individual;

[0037] - at least one detector, secured to the support, the detector(s) being adapted for detect the position of the outwardly directed illumination beam of the contact lens so as to extract the angle of deviation from the normal gaze

[0038] - at least one sensor, preferably a quadratic sensor, secured to the support, forming part of a refractometer adapted to locate the wavefront of the beam reflected by the retina and / or the lens and refracted by the eye so as to measure the refractive error of the eye taking into account the angle of deviation measured by the detector.

[0039] The contact lens is therefore coupled to at least one detector, preferably a Position Sensitive Detector (PSD) positioned in front of the eye, which allows the extraction of the angle of deviation from the normal gaze and at least one other detector which is part of a refractometer. Instead of a PSD, a camera can very well be used. The implementation of a PSD has the advantage of being simpler, less expensive and more precise.

[0040] According to a first advantageous embodiment, the refractometer is adapted to operate as an interferometer adapted to measure interference between at least one beam reflected by the retina and refracted by the eye and another illumination beam reflected by the retina.

[0041] According to this first mode, several advantageous variants can be envisaged, in particular:

[0042] - the lens comprises a VCSEL laser as an illumination source, the interferometer being adapted to measure laser back-injection interferometry between the beam inside the VCSEL cavity and a beam reflected by the retina and refracted by the eye;

[0043] - the lens comprising a VCSEL laser as an illumination source and a optical diffraction element, the interferometer being adapted to measure the interference between at least two beams diffracted by the optical diffraction element from the same beam emitted by the VCSEL laser, reflected by the retina and refracted by the eye;

[0044] - the lens comprising a VCSEL laser as an illumination source and a optical diffraction element, the interferometer being adapted to measure the interference between at least two beams, diffracted by the optical diffraction element from the same beam emitted by the VCSEL laser, one being reflected by the retina and refracted by the eye and the other being reflected by the lens and refracted by the eye.

[0045] According to a second embodiment, the auto-refractometer comprises, as part of the refractometer, a plurality of detectors, integral with the support and arranged to be distributed around the eye, the lens comprising a plurality of VCSEL lasers as an illumination source and a plurality of optical diffraction elements each associated with one of the VCSEL lasers, or a single VCSEL laser combined with at least one optical component generating several light beams directed towards said detectors, the refractometer being adapted to measure the deviation of the beams emitted sequentially by each of the VSCEL lasers, diffracted by each of the optical diffraction elements, reflected by the retina and refracted by the eye.

[0046] According to a third embodiment, the auto-refractometer comprises, as part of the refractometer, a camera secured to the support, the lens comprising a VCSEL laser as an illumination source and an optical diffraction element in the form of a hologram, the camera being adapted to analyze the deformation of the hologram pattern, reflected by the lens. This mode is suitable for measuring the accommodation of an eye.

[0047] The support of the PSD may be a frame, intended to be worn on the face of the individual, such as an eyeglass frame or an augmented reality headset or a head-up display (HUD) screen.

[0048] According to a first variant, the system comprises a single PSD detector, intended to be arranged opposite the eye, the PSD detector being transparent in the visible and sensitive in the near infrared (NIR), the illumination sources of the contact lens emitting in the near infrared.

[0049] According to a second variant, the system comprises two PSD detectors, intended to be arranged at the periphery of the eye, substantially in a plane facing the eye, so as to cover the range of angular variation of position of the eye, the PSD detectors being arranged so as not to obstruct the vision of the individual.

[0050] Thus, the invention essentially consists of a contact lens whose membrane integrates / encapsulates at least one illumination source, preferably a VCSEL laser, which sends at least one beam towards the outside of the eye to determine the direction of gaze and at least one beam for internal illumination of the eye, i.e. the lens and / or the retina. The light beam reflected by the retina is recovered by a detector and analyzed by a suitable device.

[0051] The fact that the lens according to the invention makes it possible to know the direction of gaze by the beam oriented towards the outside of the eye makes it possible to do without a fixation target as in auto-refractometers or aberrometers according to the state of the art, which leaves complete freedom of movement to the individual whose refractive error is being measured. The refractive measurement with a lens according to the invention can be carried out without the voluntary participation of the individual.

[0052] In other words, the invention is a lens, the combination of light beams of which both towards the outside of the eye and towards the inside in the direction of the crystalline lens and / or the retina, makes it possible to locate the wavefront reflected by the crystalline lens and / or by the retina and refracted by the human visual system, so as to recalibrate / align the latter and the refractometer.

[0053] Thanks to the contact lens according to the invention, a major drawback of the instruments (auto-refractometers, aberrometers) of the prior art is overcome, which forces an individual to remain motionless in front of a fixation target provided for this purpose, in order to have control over the alignment of his visual axis. Indeed, the various techniques known for objectively measuring refractive error (contrast optimization, Scheiner principle, beam deflection, aberrometry, etc.) are based for the most part on recording the reflection of light from an infrared source on the retina and require precise alignment between the infrared source, the eye, and the detector. Accommodation can be calculated from variations around the refractive error or by following similar methods but using light reflected by the lens.

[0054] With a contact lens according to the invention, the illumination source of an auto-refractometer is automatically aligned with the eye because the direction of gaze by the beam emitted from the lens is known at the time of measurement of the refractive error.

[0055] Other advantages and characteristics of the invention will become more apparent upon reading the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures. Brief description of the drawings

[0056] [Fig-1] [Fig.l] is a schematic sectional view of a contact lens according to the invention according to a first embodiment for measuring the refractive error of an individual's eye.

[0057] [Fig.2] [Fig.2] is a schematic view of a contact lens according to the invention in section according to a variant of [Fig.l].

[0058] [Fig.3] [Fig.3] a schematic view of a contact lens according to another variant of [Fig.l].

[0059] [Fig.4], [Fig.4A] Figures 4 and 4A are sectional and front views respectively of a contact lens according to the invention according to a second embodiment with the associated detectors on a support around the eye.

[0060] [Fig.5] [Fig.5] is a schematic sectional view of a contact lens according to the invention according to a third embodiment for measuring the accommodation of an individual's eye.

[0061] [Fig.6] [Fig.6] is a synoptic view showing the operation of a device electromagnetic induction recharging system for recharging the deformable battery encapsulated in a contact lens according to the invention.

[0062] [Fig.7A], [Fig.7B] Figures 7A and 7B are views showing steps of rea successive lization of a contact lens according to the invention. Detailed description

[0063] It is specified that the various elements according to the invention are represented solely for the sake of clarity and that they are not necessarily to scale.

[0064] [Fig.l] shows a contact lens 1 according to the invention for measuring the refractive error and / or the accommodation of an individual's eye.

[0065] The contact lens 1 is configured to be applied to an eye O of an individual having an optical axis X.

[0066] The eye O firstly comprises a cornea C in the form of a spherical cap at the interface with the ambient air. The eye O comprises an iris I pierced in its center by a circular opening called the pupil P through which light is transmitted. The iris I dilates or contracts depending on the light intensity. The eye O also comprises a crystalline lens CR formed by a fibrous, transparent and flexible disc to focus the incident light received through the pupil P. Behind the crystalline lens CR, on the other side of an ocular cavity OC, the eye O comprises a retina R formed of sensory cells comprising cones for daytime vision and rods for night vision. As visible in [Fig.l], the cornea C, the pupil P and the crystalline lens CR are substantially centered on the optical axis X.

[0067] The contact lens 1, preferably a rigid or hybrid scleral lens, supports by encapsulation in its membrane 10, two illumination sources 11, 12. The membrane 10 is intended to be worn by the eye O of an individual, whose anatomy has just been described.

[0068] These sources may be light-emitting diodes (LEDs) or vertical-cavity surface-emitting lasers (VCSELs) or even edge-emitting laser diodes. The light emitted in the infrared by these sources 11, 12 may be coherent (VCSELs) or weakly coherent (LEDs). Preferably, the sources 11, 12 are VCSELs.

[0069] A shape of the sources 11, 12, such as for example elliptical diodes or the installation of a shaping optic on each of the sources can be envisaged so that each light beam is in the form of a thin optical pencil in the detection zone as described below.

[0070] The contact lens may integrate within its membrane 10 a rechargeable autonomous battery which powers the sources. This battery is advantageously a deformable accumulator as described and claimed in patent application WO 2018 / 167393A1.

[0071] The membrane 10 has a disc shape domed around a central axis with a concave rear face and a convex front face. The rear face has a shape complementary to the cornea C in order to be pressed against it or at least to cover the latter in a preferred position of the contact lens 1 illustrated in [Fig.l]. In the case where the lens is a scleral lens, in the preferred position, there is no direct contact strictly speaking between the lens and the cornea C. The lens rests on the sclera and there is a reservoir of lacrimal fluid between the lens and the cornea C. In this preferred position, the contact lens 1 is centered on the optical axis X, so that the central axis of the membrane 10 is substantially coincident with the optical axis X.

[0072] The transparent membrane in contact with the cornea C is preferably made of biocompatible material, for example based on silicone hydrogel or HEMA (an English acronym for “Hydroxy Ethyl Methacrylate”). It may be any other suitable biocompatible material, as described for example in publication [1].

[0073] When the contact lens 1 is worn by an eye (O) of the individual, each illumination source 11, 12 can emit a cone or illumination beam Fl, F2.

[0074] According to the invention, the beam F1 illuminates the lens and / or the retina R of the eye, while simultaneously the beam F2 illuminates outwards in order to carry out optical pointing which makes it possible to know the direction of gaze. It is advantageous to implement the production of the beam F2 and its detection as described in patent application WO2020 / 212394.

[0075] The light beam which is reflected by the lens and / or the retina and analyzed by a refractometer, part of which is formed by a beam detector which can be, depending on the configurations, embedded in the lens and / or in a fixed support relative to the individual's eye. Knowledge of the direction of gaze makes it possible to compensate for the variable alignment of the eye with the detector sensitive to the PSD position.

[0076] Generally speaking, no illumination source 11, 12 carried by the lens 1 nor any of the detectors carried by the lens and / or a support and which allow either knowledge of the direction of gaze or for detection of the beam reflected by the lens and / or the retina, blocks the individual's view.

[0077] The detector(s) for detecting the beams F1, F2 are advantageously placed around the eye, preferably on a support carried by the individual such as glasses, as shown schematically in [Fig.4A].

[0078] Several embodiments of a contact lens 1 according to the invention can be envisaged depending on the measurement method implemented for the refractometer.

[0079] [Fig. 1] shows an embodiment for a measurement by interferometry using a single illumination source 11 which is a VCSEL laser. This laser emits the beam Fl towards the retina R creating a source point PL

[0080] This beam Fl is back-injected into the VCSEL laser 11.

[0081] This VCSEL 11 laser includes a photodiode integrated into the laser cavity.

[0082] The measurement of refractive error is based on back-injection interferometry laser.

[0083] Thus a portion of the reflected beam is injected into the cavity. The laser field inside the cavity and the back-injected laser field are in phase or out of phase, thus modulating the optical output power by self-mixing interference. A fraction of the modulated output power is measured by the photodiode, and the phase difference between the beams and therefore the length of the eye can be calculated. From the knowledge of the alignment of the eye by the beam Fl and this calculated eye length, the refractive error of the eye is determined.

[0084] [Fig.2] illustrates a variant of the measurement by interferometry. Here, the VCSEL laser 11 is associated with an optical diffraction element 13, which diffracts the beam of the laser 11 into two distinct beams F1, F3 which create two distinct source points, P1, P2 on the retina R. The light reflected by these two points P1, P2 creates an interference pattern which can be detected by one or more sensors around the eye, preferably quadratic sensors 2.1..as shown in [Fig.4A]. From the knowledge of the alignment of the eye by the beam F1 and this measurement of interference between the two beams coming from the distinct source points P1, P2, the refractive error of the eye is determined.

[0085] [Fig.3] illustrates a variant of the measurement by interferometry according to which two distinct source points PI, P2 are always created but unlike [Fig.2], one of the source points is created on the crystalline lens CR of the eye, the other of the source points being always created on the retina R of the eye. The interference pattern is therefore between the light reflected on the one hand by the source point on the crystalline lens and on the other hand on the retina R.

[0086] Figures 4 and 4A illustrate a second mode where the measurement of the refractive error is carried out not by interferometry but from the recording of a multitude of beams sent and reflected sequentially by the retina R. Thus, a plurality of VCSEL laser sources each associated with an optical diffraction element 13.1, 13.2..; is arranged in the membrane 10 of the lens while being distributed around the eye. A set of beams Fl is sent sequentially towards the retina R from the VCSEL lasers and each diffracted by one of the optical diffraction elements. Each of the beams creates a source point of its own on the retina R. The deviation of the sequential beams is recorded with a set of PSD position detectors 2.1, 2.2... placed around the eye. From the knowledge of the alignment of the eye by the beam Fl and this measurement of beam deviation, the refractive error of the eye is determined.

[0087] [Fig. 5] illustrates a third mode where the measurement of the refractive error is carried out not by interferometry, nor from a multitude of beams sent and reflected sequentially by the retina R, but by holographic analysis. Thus, the optical diffraction element 13 associated with the VCSEL laser 11 is a hologram, so as to project a holographic pattern onto the crystalline lens R. The image analysis of the deformation of the pattern by a camera 20 makes it possible to estimate the curvature of the crystalline lens R. It is advantageous to implement the production of the holographic pattern and the analysis of its deformation as described in the patent application FR3106419A1. From the knowledge of the alignment of the eye by the beam Fl and this estimation of curvature of the lens, the accommodation of the eye is determined.

[0088] In the case where the contact lens according to the invention incorporates a flexible battery for powering all of the electronic / optoelectronic components, a magnetic induction recharging system for this battery is advantageously provided. Thus, preferably an antenna in the form of an induction coil 14, connected to a rectifier, is encapsulated in a contact lens 1.

[0089] An advantageous example of a recharging system is shown in [Fig.6]: an induction antenna 30 is integrated into an eyeglass frame 3, preferably one that supports the PSD detectors. The antenna 30 transfers energy by magnetic coupling to the antenna 14 of the contact lens 1 that may be in place on the eye O of an individual during magnetic induction recharging. Reference may be made to publication [2] for further details.

[0090] Figures 7A and 7B illustrate certain steps of a method for producing a contact lens according to the invention, of the scleral type.

[0091] The membrane 10 here consists of two films 15, 16 made of transparent polymer, for example a hydrogel.

[0092] Each of the two films 15, 16 is first shaped as usual.

[0093] Then, all the electronics, with the possible exception of the induction energy collection antenna, are placed on the inner face of the outer film 15.

[0094] Thus, the electronics including the illumination sources 11, 12 and where appropriate the optical diffraction elements 13, are perfectly positioned within the film 16.

[0095] Once this positioning has been carried out, the two films 15, 16 made of transparent polymer are sealed together, for example using UV glue.

[0096] Thus, all the electronic or optoelectronic components are perfectly positioned and encapsulated between the two films 15, 16.

[0097] Other variations and improvements may be made without departing from the scope of the invention.

[0098] In the embodiment where the measurement of the refractive error is carried out from an interference created from source points on the retina, it is possible to envisage having one ([Fig.l]), two ([Fig.2]) or a multitude of source points.

[0099] As regards the light beam directed towards the outside, it can be single or multiple due to the addition of an optical diffraction element with which the beam is associated. List of cited references

[0100] [1] C. Stephen, A. Musgrave and F. Fang in the article entitled “Contact Lens Materials: A Materials Science Perspective. Materials Review, Vol. 14, 261, January 2019.

[0101] [2] Y.-J.Kim et al., « Eyeglasses-powered, contact lens-like platform with high power transfer efficiency, » Biomédical Microdevices, vol. 17, no. 4, July 2015.

Claims

Claims

1. Contact lens (1) intended to be worn by an eye of the individual, for measuring refractive error and / or accommodation of the eye, comprising: - a membrane (10) adapted to transparently cover the pupil and to cover the iris of the eye and preferably at least partially the sclera; - at least one illumination source (11, 12) encapsulated in the membrane, the illumination source(s) being adapted to emit two cones or light beams (F1, F2) whose divergence is controlled relative to the axis of the lens, one of the two beams being intended to be directed towards the inside of the membrane in the direction of the crystalline lens and / or the retina of the eye so as to create a source point on the latter, while the other of the two beams is intended to be directed towards the outside of the membrane in a direction away from the eye.

2. Contact lens (1) according to claim 1, comprising at least two separate illumination sources, one for emitting the beam intended to be directed towards the inside of the membrane in the direction of the lens and / or the retina of the eye and the other for emitting the beam intended to be directed towards the outside of the membrane in a direction away from the eye.

3. Contact lens (1) according to claim 1 or 2, comprising at least one optical diffraction element, encapsulated in the membrane and configured to receive the light beam emitted by the illumination source(s) directed towards the inside of the membrane and to diffract said beam towards the lens and / or the retina of the eye and create at least two distinct source points on the retina so as to produce interference between the beams reflected by the retina.

4. Contact lens (1) according to one of claims 1 to 3, comprising at least one other optical diffraction element, encapsulated in the membrane and configured to receive the light beam emitted by the illumination source(s) directed towards the outside of the membrane and to collimate said beam or project a target or a sight, such as a grid so as to allow the calculation of the orientation of the gaze, such as cyclo-torsions, or the addressing of one or more detectors arranged on the periphery of the eye.

5. Contact lens (1) according to one of the preceding claims, the illumination sources emitting in the infrared.

6. Contact lens (1) according to one of the preceding claims, the illumination source(s) being a light-emitting diode(s) (LED) or a vertical cavity surface-emitting laser(s) (VCSEL) or an edge-emitting laser diode(s).

7. Contact lens (1) according to claim 6, the LED or VCSEL diode(s) being provided with an optic for shaping its beam.

8. Contact lens (1) according to one of the preceding claims, comprising: - at least one interface for collecting and supplying electrical energy to the illumination sources, from outside the lens; - at least one electronic circuit adapted to activate the sources from the interface.

9. Contact lens (1) according to claim 8, comprising a battery encapsulated in the membrane and connected to the interface, the battery being adapted to be recharged from the interface and to electrically power the illumination sources and / or the optoelectronic functions associated with the illumination sources, the electronic circuit being adapted to activate the sources from the battery.

10. Auto-refractometer comprising: - at least one contact lens according to one of the preceding claims; - a support (3), intended to be positioned in a fixed manner relative to the face of the individual; - at least one detector (2), integral with the support, the detector(s) being adapted to detect the position of the illumination beam of the contact lens directed outwards so as to extract therefrom the angle of deviation relative to the normal of the gaze; - at least one sensor, preferably a quadratic sensor, integral with the support, forming a part of a refractometer adapted to locate the wavefront of the beam reflected by the retina and / or the crystalline lens and refracted by the eye so as to measure the refractive error of the eye by taking into account the angle of deviation measured by the detector.

11. An autorefractometer (1) according to claim 10, the detector being a position sensitive detector (PSD) or a camera.

12. An auto-refractometer (1) according to claim 10 or 11, the refractometer being adapted to operate as an interferometer adapted to measure interference between at least one beam reflected by the retina and refracted by the eye and another illuminating beam reflected or by the retina.

13. An autorefractometer (1) according to claim 12, the lens comprising a VCSEL laser as an illumination source, the interferometer being adapted to measure laser back-injection interferometry between the beam inside the cavity of the VCSEL and a beam reflected by the retina and refracted by the eye.

14. Auto-refractometer (1) according to claim 12, the lens comprising a VCSEL laser as an illumination source and an optical diffraction element, the interferometer being adapted to measure the interference between at least two beams diffracted by the optical diffraction element from a same beam emitted by the VCSEL laser, reflected by the retina and refracted by the eye.

15. Auto-refractometer (1) according to claim 12, the lens comprising a VCSEL laser as an illumination source and an optical diffraction element, the interferometer being adapted to measure the interference between at least two beams, diffracted by the optical diffraction element from a same beam emitted by the VCSEL laser, one being reflected by the retina and refracted by the eye and the other being reflected by the lens and refracted by the eye.

16. Auto-refractometer (1) according to claim 10, comprising, as part of the refractometer, a plurality of detectors, integral with the support and arranged to be distributed around the eye, the lens comprising a plurality of VCSEL lasers as an illumination source and a plurality of optical diffraction elements each associated with one of the VCSEL lasers, or a single VCSEL laser associated with at least one optical component generating several light beams directed towards said detectors, the refractometer being adapted to measure the deviation of the beams emitted sequentially by each of the VSCEL lasers, diffracted by each of the optical diffraction elements, reflected by the retina and refracted by the eye.

17. An auto-refractometer (1) according to claim 10, comprising, as part of the refractometer, a camera integral with the support, the lens comprising a VCSEL laser as an illumination source and an optical diffraction element in the form of a hologram, the camera being adapted to analyze the deformation of the hologram pattern, reflected by the lens.

18. Auto-refractometer (1) according to one of claims 10 to 17, the support being a frame (3), intended to be worn on the face of the individual, such as an eyeglass frame or an augmented reality headset or a head-up display (HUD) screen.

19. Auto-refractometer (1) according to one of claims 10 to 18, comprising a single PSD detector (2), intended to be arranged opposite the eye, the PSD detector being transparent in the visible and sensitive in the near infrared (NIR), the illumination source(s) of the contact lens emitting in the near infrared.

20. Auto-refractometer (1) according to one of claims 10 to 18, comprising two PSD detectors (2.1, 2.2), intended to be arranged at the periphery of the eye, substantially in a plane facing the eye, so as to cover the range of angular variation of position of the eye, the PSD detectors being arranged so as not to obstruct the vision of the individual.

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