Optical element for augmented reality equipment

Abstract

An ophthalmic lens is disclosed that is suitable for wearers whose prescription for the left eye and the right eye differ by at least 0.25 D in cylindrical power, wherein the back surface of the two ophthalmic lenses has substantially the same shape.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an ophthalmic lens adapted to a wearer whose prescription differs between the left and right eyes.

[0002] Furthermore, the present disclosure relates to a method implemented by a computer device for determining an ophthalmic lens adapted to a wearer, and to a device for determining an ophthalmic lens adapted to a wearer, the device comprising processing circuitry. BACKGROUND

[0003] It is known to provide a pair of optical lenses with optical power within an augmented / virtual reality equipment to provide optical correction to the user.

[0004] In some augmented reality equipment, it is required that the optical lenses have a reference back surface that does not vary with the prescription. Also, the back surface can have to be located at a precise distance from the eye. Therefore, it is required to control the position of the vertex of this reference back surface with respect to the corneal center or the eye rotation center. Furthermore, it can be required to fix the distance between the vertex of the reference back surface and the corneal center, independently of the wearer's prescription.

[0005] With the known solutions, adapting the back surface of the optical lenses according to the user's prescription will also affect the position of the back surface of the lenses.

[0006] For example, if the optical lenses are held by the front surface, the distance of the eye cornea from the back surface of the optical lenses or the distance of the eye rotation center from the back surface of the optical lenses depends on the lens power, the front surface curvature and the lens thickness.

[0007] If the lenses are held at the back surface, the eye-lens distance is generally larger for negative lenses and closer for positive lenses.

[0008] Therefore, depending on the wearer's refractive error, the user's field of view can vary. The field of view depends on the lens diameter and the lens proximity. Therefore, there is an interest in how to provide suitable optical lenses for augmented reality equipment.

[0009] Another problem arises with negative power lenses. Standard negative power lenses have a convex front surface with a low curvature and a concave back surface that provides most of the refractive power. If this lens is held at the front surface, the edges of the back surface of the negative lens can have a non-negligible thickness and can interfere with the wearer's eyelashes. This hinders the proposition of placing the refractive lenses very close to the wearer's eye, thus limiting the wearer's field of view.

[0010] The present invention aims to solve the above problems by providing an ophthalmic lens that can correct the wearer's refractive power, has good optical quality, minimal optical aberrations and at the same time provides a large field of view over a large range of wearer's refractive power. SUMMARY

[0011] To this end, the disclosure proposes a pair of ophthalmic lenses suitable for a wearer whose prescription for the left eye and for the right eye differs by at least 0.25 D in cylinder, wherein the back surface of the two ophthalmic lenses has substantially the same shape.

[0012] Advantageously, the pair of ophthalmic lenses is arranged in a way that facilitates the easy fixation of the pair of ophthalmic lenses in an augmented / virtual reality equipment, while taking into account the required eye-lens distance. The eye-lens distance can be defined as the distance between the vertex of the back surface of the ophthalmic lens and the center of the cornea or the center of rotation of the eye.

[0013] Another advantage is to provide a different correction for each lens of the pair of ophthalmic lenses while having substantially the same back surface and low level of aberrations to improve the correction to the wearer.

[0014] In the case of augmented reality equipment, the ophthalmic lenses are embedded in the augmented reality equipment. The fact that the front and / or back surface of the ophthalmic lenses is customized to provide the desired refractive function does not change the perception of the lens design by the people around the augmented reality equipment. The refractive function corresponds to the optical lens power (mean power, astigmatism, etc.) as a function of the gaze direction.

[0015] Providing similar back surfaces for the two lenses forming the pair of ophthalmic lenses makes it possible to maintain a given distance between the vertex of the back surface of the ophthalmic lenses and the center of the cornea or the center of rotation of the eye. The positioning of the back surface of the ophthalmic lenses relative to the cornea and / or the fixation point limits the risk of interfering with the eyelashes, eyebrows or cheeks when the equipment is close to the eye. In this way, it is possible to make the augmented reality equipment even more compact.

[0016] In addition, by determining an appropriate ophthalmic lens back surface geometry, it is possible to minimize the bounding box occupied by the ophthalmic lenses for a range of prescriptions.

[0017] According to further embodiments, which can be considered individually or in combination:

[0018] - the back surface of each ophthalmic lens has substantially the same shape within a wide range of prescriptions; and / or

[0019] - the absolute difference in surface mean sphere and the absolute difference in surface cylinder of the back surface of the two ophthalmic lenses at a given reference point is less than or equal to 0.1 D; and / or

[0020] - the absolute difference in surface mean sphere and the absolute difference in surface cylinder of the back surface of the two ophthalmic lenses at an arbitrary point on a given reference zone is less than or equal to 0.1 D, preferably less than or equal to 0.05 D; and / or

[0021] - each of the pair of ophthalmic lenses can have a flat, convex or concave back surface; and / or

[0022] - both ophthalmic lenses have flat back surfaces, wherein the absolute value of the surface mean sphere and the absolute value of the surface cylinder at any point are less than or equal to 0.25 D; or

[0023] - both ophthalmic lenses have convex back surfaces, wherein the surface mean sphere at any point is greater than or equal to +0.25 D; or

[0024] - both ophthalmic lenses have concave back surfaces, wherein the surface mean sphere at any point is less than or equal to -0.25 D; and / or

[0025] - the pair of ophthalmic lenses is adapted to be mounted in a head-mounted display device to provide vision correction to a wearer; and / or

[0026] - the specific wearing conditions are determined by the arrangement of the head-mounted display device in which the pair of ophthalmic lenses is adapted to be mounted; and / or

[0027] - each ophthalmic lens meets optical performance indicators related to the vision decrease, and / or the focusing power error and / or the residual astigmatism error on the gaze direction domain or the lens area; and / or

[0028] - each ophthalmic lens is a single-vision ophthalmic lens; and / or

[0029] - for gaze directions within 30 degrees from the main gaze direction, the absolute value of the focusing power error and of the residual astigmatism error of each single-vision ophthalmic lens is less than or equal to 0.5 D, preferably less than or equal to 0.25 D; and / or

[0030] - each ophthalmic lens has a specific front surface, for example a front surface that is not spherical, for example an aspherical front surface.

[0031] The disclosure further relates to a method for determining a pair of ophthalmic lenses adapted to a wearer implemented by a computer device, the method comprising:

[0032] - providing prescription data representative of a prescription of the wearer;

[0033] - providing wearing conditions data representative of given wearing conditions;

[0034] - providing back surface data representative of a shape of a back surface;

[0035] - determining a pair of ophthalmic lenses having a back surface according to the back surface data, and a front surface adapted to provide, in the given wearing conditions, a refractive function adapted to the provided prescription.

[0036] According to an embodiment, the method implemented by the computer device is configured for determining a pair of ophthalmic lenses adapted to a wearer, wherein the pair of ophthalmic lenses is adapted to ophthalmic lenses of a wearer whose prescription for the left eye and the right eye differ by at least 0.25 D in cylinder and wherein the back surface of the two ophthalmic lenses have substantially the same shape.

[0037] Advantageously, the pair of ophthalmic lenses is determined in a way so as to be easily fixed in an augmented / virtual reality equipment, while taking into account the required eye to lens distance.

[0038] Another advantage is to provide a different correction in each of the pair of ophthalmic lenses to improve the correction to the wearer when having low level of aberrations. Providing a similar back surface to a pair of ophthalmic lenses makes it possible to maintain a given distance between the apex of the back surface of the ophthalmic lenses and the corneal center or the center of rotation of the eye. The positioning of the back surface of the ophthalmic lenses relative to the cornea and / or the fixation point limits the risk of interfering with the eyelashes, eyebrows or cheeks when the equipment is close to the eye. In this way, the augmented reality equipment can be made even more compact.

[0039] The disclosure further relates to a device for determining a pair of ophthalmic lenses adapted to a wearer, the device comprising processing circuitry configured for:

[0040] - receiving prescription data representative of a prescription of a wearer;

[0041] - receiving wearing conditions data representative of given wearing conditions;

[0042] - receiving back surface data representative of a shape of a back surface;

[0043] - determining a pair of ophthalmic lenses having a back surface according to the back surface data and a front surface adapted to provide, under the given wearing conditions, a dioptric function adapted to the provided prescription.

[0044] According to an embodiment, the device is configured for determining a pair of ophthalmic lenses adapted to a wearer, wherein the pair of ophthalmic lenses is adapted to ophthalmic lenses of a wearer whose prescription for the left eye and the right eye differ by at least 0.25 D in cylinder and wherein the back surface of the two ophthalmic lenses have substantially the same shape.

[0045] Advantageously, the pair of ophthalmic lenses is manufactured in a way so as to be easily fixed in an augmented / virtual reality equipment.

[0046] Advantageously, the pair of ophthalmic lenses consists of a lens configured to be placed in front of the left eye and a lens configured to be placed in front of the right eye.

[0047] According to further embodiments, the disclosure relates to a pair of ophthalmic lenses adapted to a wearer, each ophthalmic lens having a different dioptric power from one another in a given wearing condition, wherein the back surface of the two ophthalmic lenses have substantially the same shape.

[0048] Advantageously, the pair of ophthalmic lenses is manufactured in a way such that at least one dioptric power of the left lens and of the right lens of the pair of ophthalmic lenses is different and the back surface of the two ophthalmic lenses have substantially the same shape. The front surface of the ophthalmic lenses is calculated according to optical performance objectives by an optimization process and machined by a surface generator.

[0049] According to further embodiments, which can be considered alone or in combination:

[0050] - each ophthalmic lens has the same refractive index; and / or

[0051] - the dioptric power of the two ophthalmic lenses has a difference in power greater than or equal to 0.25 D and / or a difference in astigmatism power greater than or equal to 0.25 D at a given reference point; and / or

[0052] - the back surface of the two ophthalmic lenses has a difference in absolute value of surface mean sphere and a difference in absolute value of surface cylinder less than or equal to 0.1 D at a given reference point; and / or

[0053] - the back surface of the two ophthalmic lenses has a difference in absolute value of mean sphere less than or equal to 0.1 D over a given reference zone; and / or

[0054] - the two ophthalmic lenses both have a flat back surface, wherein the absolute value of the surface mean sphere and the absolute value of the surface cylinder at any point are less than or equal to 0.25 D; or

[0055] - the two ophthalmic lenses both have a convex back surface, wherein the surface mean sphere at any point is greater than or equal to +0.25 D; or

[0056] - the two ophthalmic lenses both have a concave back surface, wherein the surface mean sphere at any point is less than or equal to -0.25 D; and / or

[0057] - wherein said pair of ophthalmic lenses is adapted to be mounted in a head-mounted display device to provide vision correction to the wearer; and / or

[0058] - the specific wearing conditions are determined by the arrangement of the head-mounted display device in which the pair of ophthalmic lenses is adapted; and / or

[0059] - each ophthalmic lens meets optical performance indicators related to a decrease in visual acuity, and / or a focal error and / or a residual astigmatism error over a domain of gaze directions or lens area; and / or

[0060] - Each ophthalmic lens is a single-vision ophthalmic lens; and / or

[0061] - For a gaze direction within 30 degrees of the primary gaze direction, the focal power error and residual astigmatism error of each single-vision ophthalmic lens are less than or equal to 0.5D, preferably less than or equal to 0.25D; and / or

[0062] - Each ophthalmic lens has a specific front surface, such as a non-spherical front surface, or an aspherical front surface.

[0063] This disclosure also relates to a method for determining a suitable pair of ophthalmic lenses for a wearer, implemented by a computer device, the method comprising:

[0064] - Provides prescription data indicating the wearer's prescription;

[0065] - Provides wearing condition data representing a given wearing condition;

[0066] - Provides back surface data representing its shape;

[0067] - Determine an ophthalmic lens having a posterior surface based on the posterior surface data and an anterior surface adapted to provide refractive function suitable for the given prescription under a given wearing condition.

[0068] This disclosure also relates to a device for determining a pair of ophthalmic lenses suitable for a wearer, the device including processing circuitry configured to:

[0069] - Receive prescription data representing the wearer's prescription;

[0070] - Receive wearing condition data representing the given wearing conditions;

[0071] - Receives back surface data representing its shape;

[0072] - Determine an ophthalmic lens having a posterior surface based on the posterior surface data and an anterior surface adapted to provide refractive function suitable for the given prescription under a given wearing condition.

[0073] The present invention further relates to a computer program product comprising one or more stored sequences of instructions that are accessible by a processor and, when executed by the processor, cause the processor to perform the steps of the method according to the present invention.

[0074] The present invention also relates to a computer-readable storage medium having a program recorded thereon; wherein the program causes a computer to perform the method of the present invention.

[0075] Unless otherwise specifically stated, it will be apparent from the following discussion that throughout the specification, the use of terms such as “calculation” or “operation” refers to the actions and / or processes of a computer or computing system or similar electronic computing device that manipulate and / or convert data represented as physical (e.g., electronic) quantities in the registers and / or memory of the computing system into other data similarly represented as physical quantities in the memory, registers, or other such information storage, transmission, or display devices of the computing system.

[0076] Embodiments of the present invention may include apparatus for performing the operations described herein. This apparatus may be specifically constructed for the desired purpose, or may include a general-purpose computer or a digital signal processor (“DSP”) selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer-readable storage medium, such as, but not limited to, any type of disk, including floppy disks, optical disks, CD-ROMs, magneto-optical disks, read-only memory (ROM), random access memory (RAM), electronically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic cards or optical cards, or any other type of medium suitable for storing electronic instructions and capable of being coupled to a computer system bus.

[0077] The processes presented herein are not inherently related to any particular computer or other device. Various general-purpose systems can be used with the programs taught herein, or it may prove convenient to build more specialized devices to perform the desired methods. The desired architectures of these various systems will become clear from the following description. Furthermore, embodiments of the invention are described without reference to any specific programming language. It will be appreciated that the teachings of the invention described herein can be implemented using various programming languages. Attached Figure Description

[0078] Embodiments of this disclosure will now be described by way of example only and with reference to the following accompanying drawings, in which:

[0079] - Figure 1a and Figure 1b A cross-sectional view of an ophthalmic lens according to the prior art is shown;

[0080] - Figure 2a and Figure 2b A cross-sectional view of an ophthalmic lens according to the present invention is shown;

[0081] - Figures 3a to 6d The diagrams show the refractive power and astigmatism of different embodiments of an ophthalmic lens according to this disclosure before and after optimization;

[0082] - Figures 7a to 12c The diagrams show the refractive power, astigmatism, and vertical cross-sections of different embodiments of the ophthalmic lens according to the present disclosure before and after optimization. Detailed Implementation

[0083] The elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be enlarged relative to other elements to aid in understanding the embodiments of the invention.

[0084] In the remainder of the description, terms such as “up,” “down,” “front,” “back,” or other words indicating relative position may be used. These terms should be understood when wearing the equipment that includes this pair of ophthalmic lenses.

[0085] Figure 1a and Figure 1b A cross-sectional view of an ophthalmic lens 100 and a wearer's eye 200 is shown. The ophthalmic lens 100 includes a front surface 102 and a rear surface 104. The ophthalmic lens 100 of the augmented reality device is manufactured in a manner similar to that of ophthalmic lenses for eyeglasses, wherein the rear surface 104 is machined to provide refractive function to the wearer. The front surface 102 and the rear surface are linked to each other by an edge 110.

[0086] Due to the fixing device 106, the ophthalmic lens 100 can be mounted within and held within the augmented reality device (not shown). The front surface 102 of the ophthalmic lens has an upper end 102a and a lower end 102b configured to receive the fixing device 106.

[0087] The eye 200 shown includes an eye rotation center 202 and a corneal center 204.

[0088] according to Figure 1a The ophthalmic lens 100 shown provides negative refractive power to the wearer. The ophthalmic lens 100 includes a generally slightly convex anterior surface 102 and a generally concave posterior surface 104.

[0089] according to Figure 1b The ophthalmic lens 100 shown provides positive refractive power to the wearer. The ophthalmic lens 100 includes a generally convex anterior surface 102 and a slightly concave posterior surface 104.

[0090] The eye rotation center 202 or corneal center 204 of the wearer's eye 200 needs to be located at a given eye-to-lens distance 108 from the posterior surface of the eye 104 in order to properly use the ophthalmic lens.

[0091] However, the distance between the eye and the lens depends on the refractive power of the ophthalmic lens, the curvature of the anterior surface 102, and the thickness of the ophthalmic lens 100. Compared to ophthalmic lenses 100 that provide positive refractive power, ophthalmic lenses that provide negative refractive power have a larger distance 108 between the eye and the lens.

[0092] The wearer's field of vision 112 depends on the size of the ophthalmic lens or the aperture, prescription, and distance between the eye and the lens in the augmented reality device. Then, depending on the wearer's refractive error, the field of vision 112 can vary from wearer to wearer.

[0093] In addition, such as Figure 1a The ophthalmic lens 100 shown has a generally concave rear surface 104. If the optical lens 100 is held by a fixation device 106 on the front surface 102, the edge 110 may have a non-negligible thickness and may interfere with the wearer's eyelashes, eyebrows, or cheeks.

[0094] Augmented reality equipment including ophthalmic lenses with a machined rear surface 104 (which provides most of the refractive power and is held in place by a fixation device 106 disposed in the front surface 102) prevents the ophthalmic lens 100 from getting too close to the wearer's eye 200 and thus restricts the wearer's field of vision 112.

[0095] Figure 2a and Figure 2b A cross-sectional view of an ophthalmic lens 300 and a wearer's eye 200, which are capable of solving problems related to prior art ophthalmic lenses according to the present invention, is shown.

[0096] According to the present invention, the ophthalmic lens 300 includes a first lens and a second lens, the first lens being referred to as the "left lens" (which is configured to be positioned in front of the wearer's left eye), and the second lens being referred to as the "right lens" (which is configured to be positioned in front of the wearer's right eye). The left and right lenses are adapted to the wearer, the left lens being calculated for a prescription regarding the left eye, and the right lens being calculated for a prescription regarding the right eye.

[0097] Each ophthalmic lens 300 in this pair of ophthalmic lenses has a posterior surface 304 of substantially the same shape. The prescription between the two ophthalmic lenses 300 forming a pair of ophthalmic lenses differs by at least 0.25D in cylinder power.

[0098] Each ophthalmic lens 300 in this pair of ophthalmic lenses further includes a front surface 302 that is determined to provide a prescription to the wearer.

[0099] A wearer's prescription must be understood as a set of optical characteristics (including optical power, astigmatism, and associated additional refractive power) determined by an ophthalmologist to correct their visual impairment, for example, by placing a lens in front of the individual's eye. Generally, a progressive multifocal lens prescription includes the optical power and astigmatism values ​​at the far point of vision, as well as the additional refractive power.

[0100] Here, the term "substantially identical shape" means that the shapes of the posterior surfaces 304 of the two ophthalmic lenses 300 that form a pair of ophthalmic lenses are identical in the main portion of the posterior surfaces 304. When a pair of ophthalmic lenses 300 is provided for the left and right eyes 200, there are some symmetrical geometric features.

[0101] The posterior surfaces of the lenses facing the wearer's left eye and the wearer's right eye each include a meridian, which defines a nasal portion on one side of the meridian and a temporal portion on the other side of the meridian.

[0102] The term "substantially identical shape" is further defined as symmetrical about the lens meridians with respect to the wearer's left and right eyes.

[0103] The nose portion of the lens facing the wearer's left eye and the nose portion of the lens facing the wearer's right eye are symmetrical about the meridional plane of the lens facing the wearer's left eye, at least 50%, preferably at least 80%, of the nose portion of the lens facing the wearer's right eye.

[0104] The temporal portion of the lens facing the wearer's left eye and the temporal portion of the lens facing the wearer's right eye are symmetrical about the meridional plane of the lens facing the wearer's left eye, at least 50%, preferably at least 80%, of the temporal portion of the lens facing the wearer's right eye.

[0105] The nose portion of the lens facing the wearer's right eye and the nose portion of the lens facing the wearer's left eye are symmetrical about the meridional plane of the lens facing the wearer's right eye, at least 50%, preferably at least 80%, of the nose portion of the lens facing the wearer's left eye.

[0106] The temporal portion of the lens facing the wearer's right eye and the temporal portion of the lens facing the wearer's left eye are symmetrical about the meridional plane of the lens facing the wearer's right eye and about at least 50%, preferably at least 80%, of the temporal portion of the lens facing the wearer's left eye.

[0107] The main portion of the posterior surface 304 of this ophthalmic lens 300 corresponds to 40%, preferably greater than 50%, preferably greater than 60%, and even more preferably greater than 70% of the posterior surface of the ophthalmic lens.

[0108] The front surface 302 of the ophthalmic lens 300 is machined so that the wearer’s refractive power can be corrected with sufficient optical quality (e.g., minimal optical aberration) in a manner similar to that of the known ophthalmic lens 100 (in which the rear surface 104 is machined to have the same effect).

[0109] Providing similar posterior surfaces for the two lenses forming this ophthalmic lens allows for maintaining a given distance between the apex of the posterior surface of the ophthalmic lens and the center of corneal rotation or the center of eye rotation. The positioning of the posterior surface of the ophthalmic lens relative to the cornea and / or anchor points limits the risk of interfering with eyelashes, eyebrows, or cheeks when the device is close to the eye. In this way, augmented reality devices can be made even more compact.

[0110] In a wide-range prescription, the posterior surface 304 is defined as independent of refractive power. Wide range can be defined as a prescription range encompassing -5D to 5D.

[0111] In a specific embodiment, the posterior surface 304 of each lens 300 of the ophthalmic lens 300 has the same, substantially identical posterior surface 304 for at least the refractive power range between -3D and +3D.

[0112] Because the rear surface 304 is geometrically constrained, the front surface 302 of each lens 300 of this ophthalmic lens is determined to ensure that the wearer has corrected vision, while also making the ophthalmic lens 300 clearly perceptible as aligned in the same plane when held in a head-mounted display.

[0113] In a specific embodiment, the ophthalmic lens 300 has a rear surface 304, the absolute difference between the surface mean spherical power and the absolute difference between the surface cylindrical power at a given reference point being less than or equal to 0.1D.

[0114] As is well known, the minimum and maximum radii of curvature R1 and R2 at any point on a surface can be calculated. Radius of curvature R1 and R2 can be positive or negative. R1 or R2 is positive if the center of a sphere tangent to a point on the surface with radius R1 or R2 lies in the direction of the eye relative to the surface. R1 or R2 is negative if the center of a sphere tangent to a point on the surface with radius R1 or R2 lies in the direction of the eye opposite to the surface.

[0115] It can be noted that when the surface is a local sphere, the local minimum radius of curvature R1 and the local maximum radius of curvature R2 are the same. When the surface is not aspherical, the local minimum radius of curvature R1 and the local maximum radius of curvature R2 are different.

[0116] Based on the local radii of curvature R1 and R2 of points on the surface, the local surface spherical power labeled SPH1 and SPH2 can be derived.

[0117] When the surface under consideration is the side surface of an object (also known as the front surface), these expressions are as follows:

[0118]

[0119] Where n is the refractive index of the lens's constituent materials, R1 and R2 are expressed in meters, and SPH1 and SPH2 are expressed in diopters.

[0120] If the surface under consideration is the lateral surface of the eyeball (also known as the posterior surface), then the expression is as follows:

[0121]

[0122] Where n is the refractive index of the lens's constituent materials, R1 and R2 are expressed in meters, and SPH1 and SPH2 are expressed in diopters.

[0123] As is well known, the average spherical power SPH at any point on an aspherical surface mean It can be defined by the following formula:

[0124] S mean = 1 / 2 * (SPH1 + SPH2). The surface cylindrical power CYL is also defined by the formula CYL = |SPH1 - SPH2|.

[0125] The characteristics of any aspherical surface of this lens can be expressed by the local average spherical power and cylindrical power.

[0126] If the lens is marked, the reference point can be the distance point, near point, prescription cross, or prism reference point; or if the lens is not marked, the reference point can be the optical center or prism reference point.

[0127] In a specific embodiment, the ophthalmic lens 300 has an absolute difference of surface mean spherical power and an absolute difference of surface cylindrical power of less than or equal to 0.1D, preferably less than or equal to 0.05D, at any point on the rear surface 304 of each lens in a given reference area (e.g., an area of ​​the ophthalmic lens 300 that can be defined by the frame shape of a head-mounted display device, such as an augmented / virtual reality device designed to receive the ophthalmic lens).

[0128] The reference area can be defined as a disc with a diameter greater than 5 mm and less than 10 mm centered on the reference point. The reference point can be a prism reference point, a lens fitting cross, a near or far vision point (if micro-etched on the lens), or the optical center of a non-etched monofocal lens.

[0129] In a specific embodiment, the two ophthalmic lenses 300 may have a flat rear surface, wherein the absolute values ​​of the surface mean spherical power and the absolute values ​​of the surface cylindrical power at any point are less than or equal to 0.25D.

[0130] According to an embodiment, the two ophthalmic lenses 300 may have a non-planar rear surface 304, wherein the average spherical power at any point is greater than or equal to +0.25D.

[0131] In a specific embodiment, the two ophthalmic lenses 300 may have a convex rear surface 304, wherein the average spherical power at any point is greater than or equal to +0.25D.

[0132] In another specific embodiment, the two ophthalmic lenses 300 may have a concave rear surface 304, wherein the average spherical power at any point is less than or equal to -0.25D.

[0133] Regarding this embodiment, it is assumed that the posterior surface 304 of the ophthalmic lens 300 remains identical for a range of prescriptions. In this way, a set of ophthalmic lenses can be obtained, wherein the set includes at least two different ophthalmic lenses. Considering that one ophthalmic lens is used for the left eye and one ophthalmic lens is used for the right eye, a pair of ophthalmic lenses 300 can be defined using any combination of lenses from this set.

[0134] In a specific embodiment, the ophthalmic lens 300 is adapted to be installed in a head-mounted display device to provide vision correction to the wearer.

[0135] In a specific embodiment, the specific wearing conditions are determined by the arrangement of the head-mounted display device adapted to this pair of ophthalmic lenses.

[0136] Wearing conditions may include wide-angle, wrap-around, and the distance 308 between the apex of the posterior surface 304 of the ophthalmic lens 300 and the center of the cornea 204.

[0137] Wide angle is the angle in the vertical plane between the optical axis of the ophthalmic lens (30°) and the visual axis of the eye in the first eye position (which is usually considered horizontal when the wearer is looking straight ahead).

[0138] The wrap angle is the angle in the horizontal plane between the optical axis of the ophthalmic lens (30°) and the visual axis of the eye in the first position (which is usually considered to be horizontal).

[0139] The eye-to-lens distance 308 is the distance between the vertex 310 of the posterior surface 304 of the ophthalmic lens 300 and the vertex of the cornea, typically measured along the visual axis of the eye in the first eye position and generally considered horizontal. Therefore, the eye-to-lens distance 308 can take into account the vertex of the cornea, i.e., the center of the cornea 204 or the center of rotation of the eye 202.

[0140] The ophthalmic lens 300 may have a non-zero curvature on the rear surface of each lens, so that the two ophthalmic lenses 300 can provide the same eye-to-lens distance 308 for different corrections without causing aberrations.

[0141] The rear surface 304 has an upper end 304a and a lower end 304b configured to receive a fixing device 306. The fixing device 306 allows an ophthalmic lens to be mounted in a head-mounted display device.

[0142] Head-mounted display devices can be augmented reality equipment.

[0143] The fixing device 306 holds the posterior surface 304 of the ophthalmic lens 300 such that the apex 310 of the posterior surface 304 of the ophthalmic lens should be precisely positioned at the eye-lens distance 308 from the eye rotation center 202 or the corneal center 204.

[0144] More generally, it may be desirable that, for a range of gaze directions, the eye-lens distance between the posterior surface 304 of the ophthalmic lens and the eye rotation center 202 or corneal center 204 corresponds to a specific distance that defines the area of ​​the posterior surface 304 at a precise location from the wearer's eye 200.

[0145] The distance 308 between the eye and the lens can constrain the positioning of the rear surface 304 and the geometry of each ophthalmic lens 300 in this ophthalmic lens.

[0146] The rear surface 304 includes a plurality of fixing points 312 located at the upper end 304a and the lower end 304b of the rear surface 304 of the ophthalmic lens 300, each fixing point 312 being configured to receive the fixing device 306.

[0147] Preferably, the posterior surface 304 includes at least three anchor points 312 to ensure that the ophthalmic lens 300 is uniquely positioned within the frame of the device and / or to maintain a precise distance between the eye 200 and the posterior surface 304 of the ophthalmic lens for a range of fixation.

[0148] When the posterior surface 304 of the lens is forced, the anterior surface 302 needs to be optimized to ensure the wearer's corrected visual acuity. The optimization process is similar to the usual process, except that the surface to be optimized is the anterior surface instead of the posterior surface.

[0149] The ophthalmic lens 300 according to the invention corrects the wearer’s refractive power with sufficient optical quality (e.g., minimal optical aberrations) and provides a wide field of view regardless of the wearer’s refractive power (shown in FIG. 3), thanks to the arrangement of the fixation device 306 on the posterior surface 304 of the ophthalmic lens 300.

[0150] In a specific embodiment, each ophthalmic lens 300 in this pair meets certain optical performance indicators related to decreased visual acuity and / or optical power error and / or residual astigmatism error in the gaze direction domain or lens area.

[0151] Residual astigmatism is defined as the difference between the astigmatism prescribed to the wearer and the astigmatism produced by the lens.

[0152] The gaze direction domain is defined herein as a plurality of gaze directions, which can be represented by a cone with its vertex at the center of eye rotation or any other form. All gaze directions intersect with the posterior surface 304 of the ophthalmic lens 300.

[0153] In a specific embodiment, each ophthalmic lens 300 is a single-vision ophthalmic lens.

[0154] In a more specific embodiment, for a gaze direction within 30 degrees of the primary gaze direction, the absolute values ​​of the focal power error and residual astigmatism error of each single-vision lens in this eyeglass lens are less than or equal to 0.5D, preferably less than or equal to 0.25D.

[0155] The low focal length error and residual astigmatism in the gaze direction domain, which forms a 30-degree cone with the main gaze direction, enable sufficient optical quality, such as minimal optical aberrations, to be achieved in the main domain of the wearer's gaze direction.

[0156] In another specific embodiment, the ophthalmic lens may be a bifocal, trifocal, or progressive multifocal lens.

[0157] In a specific embodiment, each ophthalmic lens 300 has a specific front surface, such as a non-spherical front surface, for example, an aspherical front surface 302.

[0158] The front surface 302 of the ophthalmic lens 300 is machined so that it can correct the wearer's refractive power with sufficient optical quality in a manner similar to that of the known ophthalmic lens 100 (in which the rear surface 104 is machined to have the same effect).

[0159] Since the front surface 302 is machined to provide the optical function and most of the refractive power of the ophthalmic lens 300, the front surface 302 of the ophthalmic lens 300 can take on different forms and therefore can be an aspherical or non-spherical surface.

[0160] This disclosure further relates to a method for determining a pair of ophthalmic lenses suitable for a wearer, implemented by a computer device, the method comprising:

[0161] - Provides prescription data indicating the wearer's prescription;

[0162] - Provides wearing condition data representing a given wearing condition;

[0163] - Provides back surface data representing the shape;

[0164] - Determine an ophthalmic lens having a posterior surface based on the posterior surface data and an anterior surface adapted to provide refractive function suitable for the given prescription under a given wearing condition.

[0165] Providing prescriptions and given wearing conditions related to the wearer makes it possible to take into account wearer-related constraints in designing this ophthalmic lens 300.

[0166] The rear surface 304 of each of the ophthalmic lenses 300 is also constrained, so that once the ophthalmic lens 300 is held in the augmented reality device by the fixing device 306, the rear apex 310 of the ophthalmic lens is located at a distance 308 from the wearer's eye rotation center 202 or corneal center specific eye-to-lens distance, regardless of the wearer's prescription.

[0167] Because the posterior surface 304 of each ophthalmic lens 300 in this pair of ophthalmic lenses is constrained, the anterior surface 302 of each ophthalmic lens 300 forming this pair is machined to provide the wearer with vision correction suitable for the provided prescription and wearing conditions.

[0168] The present invention further relates to an apparatus comprising processing circuitry adapted to store one or more sequences of instructions and to perform at least one step of the method according to the invention. The apparatus is configured to determine a suitable ophthalmic lens for a wearer by performing the following steps:

[0169] - Receive prescription data representing the wearer's prescription;

[0170] - Receive wearing condition data representing the given wearing conditions;

[0171] - Receives back surface data representing its shape;

[0172] - Determine an ophthalmic lens having a posterior surface based on the posterior surface data and an anterior surface adapted to provide refractive function suitable for the given prescription under a given wearing condition.

[0173] This method is implemented by a device that includes processing circuitry, such as a computer or microcontroller.

[0174] The present invention further relates to a computer program product comprising one or more stored sequences of instructions accessible to a processor and, when executed by the processor, causing the processor to perform the steps of the following method:

[0175] - Provides prescription data indicating the wearer's prescription;

[0176] - Provides wearing condition data representing a given wearing condition;

[0177] - Provides back surface data representing the shape;

[0178] - Determine an ophthalmic lens having a posterior surface based on the posterior surface data and an anterior surface adapted to provide refractive function suitable for the given prescription under a given wearing condition.

[0179] The present invention also relates to a computer-readable storage medium having a program recorded thereon; wherein the program causes a computer to perform the method of the present invention.

[0180] The acquisition of an ophthalmic lens 300 according to the present invention and its placement in an augmented reality device are then described in detail.

[0181] Instead of optimizing the posterior surface 304 of each ophthalmic lens when the anterior surface 302 of each lens is known, the anterior surface 302 is optimized when the posterior surface 304 is known, such that the optical performance matches, for example, an optical performance target that corresponds to the wearer's prescription and optionally takes into account the wearing conditions. The final ophthalmic lens 300 can be obtained from lens targets such as Best Form lenses or Tscherning lenses.

[0182] Further consideration will be given to the fact that an ophthalmic lens according to this disclosure includes a first ophthalmic lens and a second ophthalmic lens. When this ophthalmic lens is installed in an augmented / virtual reality device, and when the device is worn, the first ophthalmic lens and the corresponding second ophthalmic lens are configured to face the wearer's left eye and corresponding right eye, respectively.

[0183] After the first and second ophthalmic lenses of this pair of ophthalmic lenses are positioned relative to the frame of the augmented / virtual reality device, the first and second ophthalmic lenses can be defined by knowing several parameters, such as:

[0184] - The posterior surface of the first and corresponding second ophthalmic lenses, and the positioning of the first and corresponding second ophthalmic lenses (which may depend on the wearing conditions) in the first ophthalmic reference frame and the corresponding second ophthalmic reference frame;

[0185] - The refractive indices of the first and second ophthalmic lenses;

[0186] -Prescriptions for wearers related to the left and right eyes, ultimately including under-illuminated light;

[0187] - The outline or shape of the first and second ophthalmic lenses; and

[0188] -Constraints, such as minimum center, and / or the edge thickness of the first and second ophthalmic lenses, and prism thinning of progressive multifocal lenses.

[0189] Based on these inputs, the anterior surface of a spherical or toric lens can be calculated such that the curvature of the anterior surface provides the desired prescription at the reference point. If each of these ophthalmic lenses has a marking, the reference point can be the distance or near point. Otherwise, the reference point can be the optical center.

[0190] These curvatures can be estimated using the Gullstrand formula.

[0191] The first and the front surfaces of the ophthalmic lens can be modified independently through an optimization process to minimize the difference between the target optical performance and the optical performance of this ophthalmic lens.

[0192] Optimization can be achieved through an iterative process, where the merit function represents the difference in one or more optical parameters (e.g., wearer power and / or astigmatism) over a gaze direction domain defined by a cone with a given angle.

[0193] This optimization process can take into account the mounting parameters of the positioning of the posterior surfaces of the first and second ophthalmic lenses relative to the augmented / virtual reality equipment.

[0194] The anterior surfaces of the first and second ophthalmic lenses of this pair of lenses can be modeled using Zernike polynomials, B-splines, or NURBS.

[0195] The merit function can be the sum of squared residuals between the optical performance of the target ophthalmic lens and ophthalmic lens 300. Optical performance should be understood as the wearer's optical power and / or astigmatism and / or visual impairment.

[0196] The merit function is preferably calculated over the surface area defined by the contours of the first and second ophthalmic lenses.

[0197] In some embodiments, the translation and rotation of the anterior surfaces and / or from the anterior surface to the posterior surface of the first and second ophthalmic lenses are adjusted such that the optical power of the first and second lenses at the far point of vision corresponds to the prescription for the wearer's left and right eyes, and all constraints regarding the prescription and geometry of the posterior surfaces of the first and second ophthalmic lenses are satisfied.

[0198] Figures 3a to 9b Different embodiments of ophthalmic lenses according to this disclosure are disclosed. In these different embodiments of this disclosure, the material of one lens is Mr8. This ophthalmic lens is installed in an augmented / virtual reality device according to the following installation parameters:

[0199] --6° wide angle;

[0200] -0° wrap angle; and

[0201] -12mm is the distance between the cornea of ​​the eye and the back surface of the ophthalmic lens.

[0202] In Figures 3a to 6d In a corresponding embodiment, the rear surface of the ophthalmic lens is flat. Figures 3a to 3d The first embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of +4D, which is configured to be placed in front of the wearer's left eye. Figures 4a to 4d The second embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of +5D, a cylindrical power of -2D, and a cylindrical axis of 0 degrees, and the lens is configured to be placed in front of the wearer's right eye. Figure 3a and Figure 4a The image shows the optical power map before optimization, where the front surface of the ophthalmic lens is spherical or tortuous. Figure 3b and Figure 4b The optical density map after the front surface has been optimized is shown. Figure 3c and Figure 4c The image shows the astigmatism pattern before optimization, while... Figure 3d and Figure 4d The optimized astigmatism diagram is shown. It's important to note that once optimized, the difference between the minimum and maximum values ​​of optical power and astigmatism becomes less significant, thus making the lenses more comfortable for the wearer.

[0203] Figures 5a to 5d A third embodiment is shown, in which the ophthalmic lens is a single-vision lens with a spherical power of -4D, and the lens is configured to be placed in front of the wearer's left eye. Figures 6a to 6d The fourth embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of -3D, a cylindrical power of -2D, and a cylindrical axis of 0 degrees, and the lens is configured to be placed in front of the wearer's right eye. Figure 5a and Figure 6a The image shows the optical power map before optimization, where the front surface of the ophthalmic lens is spherical or tortuous. Figure 5b and Figure 6b The optimized optical focal length map is shown. Figure 5c and Figure 6c The image shows the astigmatism pattern before the anterior surface of the ophthalmic lens was optimized, and Figure 5d and Figure 6d The optimized astigmatism diagram is shown. It's important to note that once optimized, the difference between the minimum and maximum values ​​of optical power and astigmatism becomes less significant, thus making the lenses more comfortable for the wearer.

[0204] Regarding the embodiments listed below, the posterior surface of the ophthalmic lens is flat, convex, or concave, and in a wide range of prescriptions, the posterior surfaces of one of the left and right ophthalmic lenses have the same, substantially identical posterior surfaces.

[0205] Figures 7a to 7cA fifth embodiment is shown, in which the ophthalmic lens is a single-vision lens with a spherical power of +5D, and the rear surface is flat. Figures 8a to 8c The sixth embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of -7D and the rear surface is flat. Figure 7a and Figure 8a The image shows the optical power after the front surface of the ophthalmic lens has been optimized. Figure 7b and Figure 8a The optimized astigmatism map is shown. Figure 7c and Figure 8c A vertical cross-section of an ophthalmic lens according to this embodiment is shown.

[0206] The fifth and sixth embodiments disclose good optical performance for a wide range of spherical powers from -7D to +5D, wherein the optical lenses configured to be positioned in front of the wearer's left and right eyes have substantially the same flat rear surface.

[0207] Figures 9a to 9c A seventh embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of +5D, and the rear surface is a concave spherical surface with a surface spherical power of -4.54D. Figures 10a to 10c The eighth embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of -7D, and the rear surface is a concave spherical surface with a surface spherical power of -4.54D. Figure 9a and Figure 10a The image shows the optical power of the front surface of the ophthalmic lens after optimization. Figure 9b and Figure 10b The optimized astigmatism map is shown. Figure 9c and Figure 10c A vertical cross-section of an ophthalmic lens according to this embodiment is shown.

[0208] The seventh and eighth embodiments disclose good optical performance over a wide range of spherical powers from -7D to +5D, wherein the optical lenses configured to be positioned in front of the wearer's left and right eyes have substantially the same concave rear surface.

[0209] Figures 11a to 11c A ninth embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of +5D, and the rear surface is a convex spherical surface with a surface spherical power of +4.54D. Figures 12a to 12c The tenth embodiment is shown, wherein the ophthalmic lens is a single-vision lens with a spherical power of -7D, and the rear surface is a convex spherical surface with a surface spherical power of +4.54D. Figure 11a and Figure 12a The image shows the optical power of the front surface of the ophthalmic lens after optimization. Figure 11b and Figure 12b The optimized astigmatism map is shown. Figure 11c andFigure 12c A vertical cross-section of an ophthalmic lens according to this embodiment is shown.

[0210] The ninth and tenth embodiments disclose good optical performance over a wide range of spherical powers from -7D to +5D, wherein the optical lenses configured to be positioned in front of the wearer's left and right eyes have substantially the same convex rear surface.

[0211] The present disclosure has been described above by way of embodiments without limiting the general inventive concept.

[0212] Many further improvements and variations can be proposed by those skilled in the art based on the above exemplary embodiments. These exemplary embodiments are given by way of example only and are not intended to limit the scope of this disclosure, which is determined solely by the appended claims.

[0213] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a (a) or (an)" does not exclude a plural. The mere fact that different features are described in mutually different dependent claims does not imply that combinations of these features cannot be used advantageously. Any reference numerals in the claims should not be construed as limiting the scope of this disclosure.

Claims

1. An ophthalmic lens prescription suitable for a wearer whose left and right eyes differ in cylinder power by at least 0.25D. in, The two posterior surfaces of the two ophthalmic lenses in a pair of ophthalmic lenses have substantially the same shape, that is, the shapes of the posterior surfaces of the two ophthalmic lenses are the same for at least 50% of the posterior surface area of ​​the two lenses, and are symmetrical over at least 80% of the area between the nasal and temporal portions. Within a wide range of prescriptions including -5D to 5D, the posterior surface of each ophthalmic lens has substantially the same shape, wherein the posterior surface is defined independently of the refractive power within the range, making it possible to obtain a set of ophthalmic lenses, each of which has the same substantially identical posterior surface applicable to different prescriptions within the range.

2. The ophthalmic lens according to claim 1, wherein, The absolute difference between the average spherical power and the absolute difference between the cylindrical power of the two ophthalmic lenses at a given reference point is less than or equal to 0.1D.

3. A pair of ophthalmic lenses according to claim 1 or 2, wherein, The pair of ophthalmic lenses is suitable for mounting in a head-mounted display device, wherein the absolute difference between the surface mean spherical power and the absolute difference between the surface cylindrical power of the rear surfaces of the two ophthalmic lenses at any point on a given reference area is less than or equal to 0.1D, and the reference area is defined by the shape of the frame of the head-mounted display device.

4. A pair of ophthalmic lenses according to claim 1 or 2, wherein, Both ophthalmic lenses have a flat posterior surface, wherein the absolute values ​​of the average spherical power and the absolute values ​​of the cylindrical power at any point are less than or equal to 0.25D.

5. A pair of ophthalmic lenses according to claim 1 or 2, wherein, Both ophthalmic lenses have a non-planar posterior surface, wherein the average spherical power of the surface at any point is greater than or equal to +0.25D.

6. A pair of ophthalmic lenses according to claim 1 or 2, wherein, Both ophthalmic lenses have a convex rear surface, wherein the average spherical power of the surface at any point is greater than or equal to +0.25D.

7. An ophthalmic lens according to claim 1 or 2, wherein, Both ophthalmic lenses have a concave rear surface, wherein the average spherical power of the surface at any point is less than or equal to -0.25D.

8. A pair of ophthalmic lenses according to claim 1 or 2, wherein, The ophthalmic lens is adapted to be installed in a head-mounted display device to provide vision correction to the wearer.

9. A pair of ophthalmic lenses according to claim 1 or 2, wherein, The specific wearing conditions are determined by the arrangement of the head-mounted display device adapted to the aforementioned pair of ophthalmic lenses.

10. An ophthalmic lens according to claim 1 or 2, wherein, Each of the ophthalmic lenses is a single-vision ophthalmic lens.

11. The ophthalmic lens according to claim 10, wherein, For a gaze direction within 30 degrees of the primary gaze direction, the absolute values ​​of the focal power error and residual astigmatism error of each single-vision ophthalmic lens are less than or equal to 0.5D.

12. An ophthalmic lens according to claim 1 or 2, wherein, Each of the ophthalmic lenses has a specific front surface.

13. The ophthalmic lens according to claim 12, wherein, Each of the ophthalmic lenses has a non-spherical front surface.

14. An ophthalmic lens according to claim 12, wherein, Each of the ophthalmic lenses has an aspherical front surface.

15. A method implemented by a computer device for determining a pair of ophthalmic lenses according to any one of claims 1-14, the method comprising: - Provide prescription data representing the wearer's prescription; - Provides wearing condition data representing a given wearing condition; - Provides back surface data representing the shape; - Determine an ophthalmic lens having a posterior surface shaped according to the posterior surface data and an anterior surface adapted to provide refractive function suitable for the given prescription under the given wearing conditions.

16. An apparatus for determining a pair of ophthalmic lenses according to any one of claims 1-14, comprising processing circuitry configured to: - Receive prescription data representing the wearer's prescription; - Receive wearing condition data representing a given wearing condition; - Receives back surface data representing the shape; - Determine an ophthalmic lens having a posterior surface based on the posterior surface data and an anterior surface adapted to provide refractive function suitable for the provided prescription under the given wearing conditions.

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