Accessory device for testing eye of subject under near or mid-vision conditions

Abstract

The invention relates to an attachment device (2) for testing an eye (E1, E2) of a subject under near or mid-vision conditions, designed to be used with an optometry device (1) for measuring a subjective refractive value of the eye (E1, E2), the optometry device (1) comprising:-a refractive test unit (10) having optical components (11A, 12A), the invention relates to a dioptric test system (1) comprising:-a dioptric test unit (10) comprising optical means for providing different refractive powers to a subject's eye (E1, E2) during a subjective dioptric test, and-a display unit (20) adapted to generate a visual target (T1, T2) for the subject's eye (E1, E2), an image of said visual target (T1, T2) being visible by said dioptric test unit (10) along a reference viewing direction (OBS1), the accessory device (2) comprises an optical portion (40) configured to be mounted on a refractive test unit (10) of an optometry device (1), the optical portion comprising an optical system (41, 42) configured to deflect an image of a visual target (T1, T2) from said reference viewing direction (OBS1) towards an oblique viewing direction (OBS2, OBS3), the visual target (T1, T2) being positioned in the oblique viewing direction (OBS2, OBS3), and the visual target (T1, T2) being positioned in the oblique viewing direction (OBS2, OBS3). The invention relates to an optometry device (1) comprising a reference observation direction (OBS1) along which an image of a refractive test unit (10, T2) is visible through the refractive test unit (10) and an optical portion (40) of an attachment device (2), said inclined observation direction (OBS2, OBS3) defining a non-zero angle (A1, A2) with said reference observation direction (OBS1) when the optical portion (40) is mounted on said refractive test unit (10) of the optometry device (1). A2) and corresponds to a downward gaze direction of the subject and / or a convergent gaze direction of the subject.

Description

Technical Field

[0001] The present invention relates to an accessory device for testing the eyes of a subject. The present invention also relates to an optometry system including such an accessory device used in association with a conventional optometry device and an associated method. Background Art

[0002] Known devices and methods for testing the eyes of a subject are generally specifically designed to test the eyes under far vision conditions. Under far vision conditions, the visual targets presented to the subject to test their binocular far vision are typically placed more than 5 meters away from the subject's eyes, preferably between 3 meters and 5 meters.

[0003] However, under near vision and / or intermediate vision conditions, the refractive characteristics of the eyes may be different from those under far vision. Among other reasons, this may be due to the fact that under near vision and / or intermediate vision conditions, the accommodation and convergence of the eyes are different. It is known that the required visual correction is not the same under near vision with horizontal gaze and downward gaze.

[0004] It is also known that accommodation is not the same in binocular and monocular vision and that accommodation varies according to the gaze orientation and the vision used (monocular or binocular).

[0005] Furthermore, accurate values of the refractive characteristics of the eyes or the required visual correction diopters are typically obtained by subjective measurement methods using an optometry device suitable for performing such a subjective determination of the refractive characteristics of the eyes.

[0006] Known methods for testing the eyes of a subject under near vision and / or intermediate vision conditions are implemented with the subject wearing a trial frame equipped with trial lenses. This method does not allow accurate control of the refractive conditions (gaze inclination, posture, object and eye-lens distance, etc.) and does not allow the trial lenses to be maintained centered in front of the subject's eyes. Unwanted aberrations (oblique astigmatism caused by non-vertical incidence angles of the gaze on the lenses) may be caused, resulting in deviations that are not conducive to determining the visual correction required by the subject.

[0007] Alternative known methods for testing the eyes of a subject under near vision and / or intermediate vision conditions use an optometry device (also known as a phoropter), which will help ensure centering of the optics on the visual axis, eye-lens distance, posture control, and object (visual target) distance, thus avoiding unwanted aberrations.

[0008] Such a phoropter includes a refractive testing unit and a support element designed to receive the head of an individual and hold it in a predetermined position relative to the refractive testing unit.

[0009] This refractive testing unit houses one or more trial lenses providing different visual corrections, which can be successively placed in front of the subject's eyes until the appropriate visual correction is found.

[0010] In practice, multiple trial lenses can be located on two disks, which are mounted for free rotation. Thus, the trial lenses on these disks can be successively positioned in front of the corresponding subject's eyes. Alternatively, a single lens with variable focal power can be placed in front of the subject's eyes, optionally in association with other lenses.

[0011] A phoropter typically only allows measurements to be made along the subject's straight-ahead gaze direction, resulting in unnatural postures for near and / or intermediate vision.

[0012] Some phoropters can be used along the subject's downward or convergent gaze directions. However, all existing phoropters do not allow the subjective value of eye refraction to be determined during downward gaze without any complex and demanding positioning steps. In fact, such determination requires the rotation of the refractive unit of the phoropter to place it in front of the eyes of a subject looking downward. The refractive unit of known phoropters rotates about an axis far above the eyes, causing large variations in the inclination at the height of the phoropter, thus requiring a complete repositioning of the subject. Moreover, the ergonomics of the phoropter do not allow for downward gaze while maintaining proper alignment of the eyes and the phoropter optics under comfortable conditions: the shape of the phoropter tends to pinch the nose or rest against the subject's cheekbones. In addition, the conditions for near and / or intermediate vision testing are uncomfortable for the patient and not easy to control for eye care practitioners. Summary of the Invention

[0013] Accordingly, an object of the present invention is to provide an accessory device that can be used with an optometry device for testing a subject's eyes under near or intermediate vision conditions, in comfortable and near-natural near or intermediate vision conditions, without cumbersome adjustments.

[0014] According to the present invention, this is achieved by providing an accessory device for testing a subject's eyes under near or intermediate vision conditions, which is designed to be used in conjunction with an optometry device for measuring the subjective refractive value of an eye, said optometry device comprising:

[0015] - a refractive testing unit having optical components for providing different refractive powers to the subject's eyes during subjective refractive testing, and

[0016] - A display unit adapted to generate a visual target for the eyes of the subject, an image of the visual target being visible through the refractive test unit along a reference viewing direction.

[0017] The accessory device includes an optical portion configured to be mounted on the refractive test unit of the optometry device. The optical portion includes an optical system configured to deflect an image of the visual target from the reference viewing direction towards an inclined viewing direction, the image of the visual target being visible through the refractive test unit and the optical portion of the accessory device along the inclined viewing direction. When the optical portion is mounted on the refractive test unit of the optometry device, the inclined viewing direction defines a non-zero angle with the reference viewing direction and corresponds to the downward gaze direction of the subject and / or the convergent gaze direction of the subject.

[0018] This accessory device is designed to be used with a conventional optometry device.

[0019] Thanks to the accessory of the present invention, it is thus possible to use a conventional optometry device to easily perform subjective visual tests on the eyes of a subject under near vision and / or intermediate vision conditions, even if the conventional optometry device itself only allows distance vision measurements.

[0020] By mounting the accessory device of the present invention on the optometry device, it is indeed possible to modify the optical path along which light is guided from the visual target to the eyes of the subject. Inside the optometry device, in the absence of the accessory device, light is guided along a reference optical path corresponding to the horizontal straight-ahead viewing direction of the subject under distance vision conditions. The accessory device changes the optical path along which light is guided to a final optical path. In the final optical path, light is deflected from the reference optical path towards a direction that differs from the reference optical path by a non-zero angle and corresponds to the downward gaze direction and / or the convergent gaze direction of the subject under near vision or intermediate vision conditions.

[0021] The downward gaze direction forms a non-zero angle with the horizontal straight-ahead reference viewing direction in a vertical plane passing through the reference viewing direction. The convergent gaze direction forms a non-zero angle with the horizontal straight-ahead reference viewing direction in a horizontal plane passing through the reference viewing direction.

[0022] In other words, incident light rays entering the accessory device along a horizontal straight-ahead incident direction are deflected by the optical system and leave the accessory device along an inclined exit direction that forms a non-zero angle with the horizontal straight-ahead incident direction in at least one of the horizontal plane and the vertical plane, each plane passing through the reference viewing direction.

[0023] Due to the present invention, an optometry device initially configured to determine the vision correction power along the direct gaze direction of a subject can be used to subjectively refract the eyes of the subject along a downward gaze and / or a convergent gaze.

[0024] Further non-limiting features of the device according to the present invention:

[0025] - The optical system includes a reflective or semi-reflective surface and / or an optical lens;

[0026] - The optical system includes two optical elements, wherein a first optical element of the two optical elements is configured to be placed at an effective position in front of the exit aperture of the optometry device to deflect the image of the visual target and transmit it to a second optical element of the two optical elements, and the second optical element is configured to deflect the image of the visual target along the inclined viewing direction;

[0027] - The first optical element is movable between the effective position and a second position, at the effective position, the first optical element is placed in front of the optical component in the reference viewing direction of the optometry device, and at the second position, the first optical element is placed outside the reference viewing direction;

[0028] - The accessory device includes a determination tool configured to determine the vision correction power of the subject's eyes in consideration of the final value of a parameter representing the relative position of the eyes and the optical component of the optometry device in the presence of the accessory device;

[0029] - The determination tool is configured to determine the vision correction power in consideration of the refractive power provided by the refractive test unit of the optometry device during the subjective refraction test;

[0030] - The determination tool is configured to determine the vision correction power according to the value of a parameter representing the relative position of the image of the visual target seen through the accessory device and the subject's eyes;

[0031] - The determination tool is configured to determine the vision correction power according to a reference value of a parameter representing the relative position of the eyes and the optical component of the optometry device in the absence of the accessory device; for example, a reference value of the optical vertex distance between the eyes and the optical component of the optometry device;

[0032] - The determination tool includes a software part programmed to calculate the vision correction power;

[0033] - The optometry device includes a control device, which is programmed to determine a reference visual acuity correction power of the subject's eye by taking into account the refractive power provided by the refractive test unit to the subject's eye and a reference value of a parameter representing the relative position of the eye and the optical component in the absence of the accessory device, and the software part is configured to be implemented by the control device of the optometry device;

[0034] - The accessory device includes an adjustment tool, which is configured to adjust the position and / or orientation of each visual target displayed by the display unit based on the inclination of the inclined viewing direction, and / or adjust the refractive power of the optical component of the optometry device based on the value of a parameter representing the relative position of the image of the visual target and the subject's eye;

[0035] - The determination tool includes a database, which includes data related to the visual acuity correction power of the subject's eye, and the data is associated with the value of the parameter representing the relative position of the subject's eye and the optical component of the optometry device in the presence of the accessory device;

[0036] - The optical part includes a housing, the optical system is accommodated in the housing, and the housing is configured to be attached to the refractive test unit of the optometry device;

[0037] - The refractive test unit of the optometry device has two optical components for providing different refractive powers to the two eyes of the subject. The optical part of the accessory device includes two optical systems, each optical system is configured to be placed in front of one of the two optical components of the optometry device, so as to allow testing of the subject's eyes under binocular vision. Each optical system includes the first optical element and the second optical element. The two first optical elements extend in the same first plane, and the two second optical elements extend in the same second plane. The relative position and / or orientation of the two first optical elements and the relative position and / or orientation of the two second optical elements are fixed; and,

[0038] - The refractive test unit of the optometry device has two optical components for providing different refractive powers to the two eyes of the subject. The optical part of the accessory device includes two optical systems, each optical system being configured to be placed in front of one of the two optical components of the optometry device, thereby allowing the eyes of the subject to be tested under binocular vision. Each optical system includes the first optical element and the second optical element. The position and / or orientation of each first optical element of the optical system is independently adjustable from each other, and the position and / or orientation of each second optical element of the optical system is independently adjustable from each other;

[0039] - The refractive test unit of the optometry device has two optical components for providing different refractive powers to the two eyes of the subject. The optical part of the accessory device includes two optical systems configured to be placed in front of the two optical components of the optometry device, thereby allowing the eyes of the subject to be tested under binocular vision. Each optical system includes the first optical element and the second optical element. The position and / or orientation of each first optical element in the group is independently adjustable from each other, and the relative position and / or orientation of the second optical elements in the group is fixed;

[0040] - The software part is configured to determine the vision correction power based on a reference vision correction power, a reference value of the distance between the subject's eyes and the optical component of the optometry device, and a final value of the distance between the subject's eyes and the optical component;

[0041] - The software part is configured to determine the vision correction power taking into account the distance between the image of the visual target seen through the optometry device and the accessory device and the subject's eyes;

[0042] - The vision correction power corresponds to the equivalent power when the distance between the eye and the optical component of the optometry device is a predetermined standard distance;

[0043] - The vision correction power is calculated using a predetermined formula or a ray tracing algorithm;

[0044] - The software part is configured to adjust the position and / or orientation of each visual target displayed by the display unit based on the inclination of the tilted viewing direction.

[0045] The present invention also relates to an optometry system, the optometry system including the accessory device as described above and an optometry device for measuring the subjective refractive value of the eye, the optometry device including:

[0046] - A refractive testing unit having an optical component for providing different refractive powers to the eyes of the subject, and

[0047] - A display unit adapted to generate a visual target for the eyes of the subject, the image of which is visible through the refractive testing unit of the optometry device along a reference viewing direction,

[0048] wherein the optical portion of the accessory device is mounted on the refractive testing unit.

[0049] The optical system is configured to deflect the image of the visual target from the reference viewing direction towards an inclined viewing direction, the inclined viewing direction defining a non-zero angle with the reference viewing direction.

[0050] Advantageously, the optical system is configured to be positioned at a predetermined fixed position relative to the eyes of the subject, wherein the center of rotation of the eyes lies on the reference viewing direction and the inclined viewing direction.

[0051] The present invention also provides a method for testing the eyes of a subject under far vision and near vision or intermediate vision conditions using an optometry system as described above, the method comprising:

[0052] - Performing a visual test under far vision conditions when the subject observes the image of one or more visual targets displayed by the display unit of the optometry device along the reference viewing direction, the image not being deflected by the accessory device,

[0053] - Using the accessory device to deflect the image of the visual target towards the inclined viewing direction,

[0054] - Performing a visual test under near vision or intermediate vision conditions when the subject observes the image of the visual target displayed by the display unit of the optometry device along the inclined viewing direction, the image being deflected by the accessory device, and without moving the refractive testing unit between performing the visual test under far vision conditions and performing the visual test under near vision or intermediate vision conditions.

[0055] Advantageously, according to the method of the present invention, the visual test can also be performed under near vision or intermediate vision conditions without moving the head of the subject. Detailed Description

[0056] The following description with reference to the accompanying drawings will make clear what is included in the present invention and how the present invention can be implemented. The present invention is not limited to the embodiments shown in the drawings. Accordingly, where a feature mentioned in the claims is followed by a reference sign, the inclusion of such reference sign is for the sole purpose of enhancing the intelligibility of the claim and in no way limits the scope of the claim.

[0057] In the drawings:

[0058] - Figure 1 is a schematic view of the optical arrangement of a refractometry device according to the prior art for measuring the refraction of a subject's eye under far vision conditions,

[0059] - Figure 2 is a schematic view of the optical arrangement of a refractometry system according to the present invention, the refractometry system including an accessory device coupled to Figure 1 the refractometry device, the accessory device being configured to measure the refraction of a subject's eye under near vision or intermediate vision conditions while looking downward,

[0060] - Figure 3 is Figure 2 a schematic view of a refractometry system configured to measure the refraction of a subject's eye under far vision conditions along a straight-ahead horizontal gaze direction,

[0061] - Figure 4 is a schematic view of Figure 2 a refractometry system seen from above, the refractometry system being configured to measure the refraction of a subject's eye under near vision or intermediate vision conditions along a convergent gaze,

[0062] - Figure 5 is Figure 2 a schematic view of a refractometry system showing a first embodiment of the accessory device of the present invention mounted on the refractometry device,

[0063] - Figure 6 is an enlarged front view of the Figure 5 accessory device mounted on the refractometry device,

[0064] - Figure 7 is a schematic contour view of a subject looking through the Figure 5 accessory device, wherein the accessory device is configured to measure the refraction of the subject's eye under far vision conditions,

[0065] - Figure 8 is a schematic contour view of a subject looking through the Figure 5 accessory device, wherein the accessory device is configured to measure the refraction of the subject's eye under near vision or intermediate vision conditions along a convergent gaze,

[0066] - Figure 9Schematic front view of the second embodiment of the accessory device of the present invention,

[0067] - Figure 10 Schematic view of an optometry system of the present invention having a first variant of an accessory device, wherein the accessory device includes two optical systems adapted to be placed in front of one eye of a subject, each optical system having a fixed global position and orientation relative to the optometry device, and each optical system including first and second optical elements, the first optical elements of the two optical systems being made of a single piece, and the second optical elements of the two optical systems being made of a single piece,

[0068] - Figure 11 Schematic view of an optometry system of the present invention having a second variant of an accessory device, wherein the accessory device includes two optical systems, each of the two optical systems being placed in front of one eye of a subject, the optical elements of the two optical systems being separated from each other but remaining in fixed positions and orientations relative to the optometry device, not necessarily aligned with the optical axis of the optical components of the optometry device,

[0069] - Figure 12 Schematic view of an optometry system of the present invention having a third variant of an accessory device, wherein the accessory device includes two optical systems, each of the two optical systems being placed in front of one eye of a subject, the two optical systems being separated from each other and independently associated with a part of the optometry device, wherein the optical elements of each optical system are aligned with the optical axis of the optical components of the optometry device,

[0070] - Figure 13 Example of a visual target displayed by an optometry device,

[0071] - Figure 14 Presents when the accessory device is in the Figure 12 configuration shown in and paired with the optometry device, the Figure 13 images of the visual target seen by each eye of the subject,

[0072] - Figure 15 Is Figure 14 superposition of two images of the visual target,

[0073] - Figure 16 Is an example of a visual target corrected by the software part of the accessory device when the accessory device is coupled to the optometry device in the Figure 12 configuration shown in,

[0074] - Figure 17 Is the Figure 16 superposition of two images of the visual target seen by the subject's eye through the accessory device,

[0075] and

[0076] - Figure 18 is an optical scheme of an optometry system for calculating the refractive correction power and the optical arrangement of a subject's eye.

[0077] In the following description, the same or corresponding elements of the embodiments and variations of the present invention will be marked with the same reference numerals.

[0078] The direction of light propagation is indicated by arrows.

[0079] The present invention relates to an accessory device 2 for testing a subject's eye under near or intermediate vision conditions when used in conjunction with an optometry device 1.

[0080] The present invention also relates to an optometry system 3 comprising an optometry device 1 and an accessory device 2 mounted thereon.

[0081] The optometry device 1 is configured to measure the subjective value of the eye's refraction by determining the reference refractive correction power required for the subject's eye to achieve a target visual performance, as explained in more detail below. Figure 1 A schematic diagram of an optometry device according to the prior art without the accessory device 2 is shown. Figures 2 to 4 and Figures 6 to 12 A schematic diagram of the optometry system 3 of the present invention is shown, which comprises an optometry device 1 similar to Figure 1 and the accessory device 2 of the present invention.

[0082] Typically, the subjective test comprises a number of steps, during each of which the subject is required to compare two different optical situations taking into account the test values of the optical characteristics of the optical components of the optometry device (such as spherical power and / or cylindrical power and / or axis). Thus, the subjective test corresponds to a series of steps. Depending on the subject's feedback to this comparison (the subject's answer), the eye care professional increments the test value, and in the next step of the subjective test, two new different optical situations are presented to the subject based on the incremented test value. This process is repeated until the subject gives a specific answer or combination of answers. An example of such an optometry device 1 is presented in Figures 1 to 12 on.

[0083] The optometry device 1 is commonly referred to as a "phoropter". It is a conventional optometry device and can be of any type known to those skilled in the art. It can be manual or automatic. It can include a virtual reality headset which includes a light field display.

[0084] Such an optometry device 1 and its use in subjective refraction testing are known, and only its main features will be described below.

[0085] As shown schematically in Figures 1 to 3 the optometry device 1 includes a refractive test unit 10 and a display unit 20. The optometry device 1 is generally used to preferably test the eyes of a subject under far vision conditions.

[0086] Known subjective refractive tests can be performed under binocular or monocular vision conditions. The subjective test for determining the refractive correction power can preferably be performed under binocular vision conditions. The full refractive subjective test or the subjective test for determining the add power can be performed along the reference observation direction OBS1 under near vision conditions.

[0087] The refractive test unit 10 of the optometry device 1 at least includes optical refractive elements 11, 12 for providing different refractive powers to the eyes of the subject.

[0088] The optometry device 1 is preferably used for binocular measurements, so as to binocularly determine at least one refractive characteristic of the first eye E1 and / or the second eye E2 of the subject.

[0089] However, it can also be used for monocular measurements. A phoropter with one optical refractive element and one displayed image can be considered for monocular measurements.

[0090] The binocular determination of the refractive characteristics of the eyes is based on binocular measurements performed with the subject's two eyes E1, E2 open and unobstructed.

[0091] The refractive test unit 10 of the optometry device 1 thus has two optical refractive elements 11, 12 for providing different refractive powers to the two eyes E1, E2 of the subject, as Figure 4 shown.

[0092] The refractive test unit 10 includes a first optical refractive element 11 adapted to provide different refractive correction powers along a first optical axis OA1 and a second optical refractive element 12 adapted to provide different refractive correction powers along a second optical axis OA2( Figure 4 and Figures 10 to 12 ).

[0093] The first optical refractive element 11 is configured to provide a first correction power to the first eye E1 of the subject, while the second optical refractive element 12 is configured to provide a second correction power to the second eye E2 of the subject.

[0094] In the optometry device 1 shown in the drawings and described below, each of the first and second optical refractive elements 11, 12 at least includes optical components 11A, 12A, such as lenses or mirrors or prisms, or a group of such optical components, and this group has adjustable refractive power characteristics or allows the adjustment of the refractive power by the rotation or translation of these optical components or by an electrical command.

[0095] In practice, the optical components 11A, 12A include, for example, lenses with variable dioptric power. Here it includes deformable liquid lenses with adjustable shape. Thus, the aforementioned optical axes OA1, OA2 correspond to the optical axes of the corresponding lenses.

[0096] Each of the optical components 11A, 12A may include a lens with variable spherical power and a lens with variable cylindrical power and variable cylindrical axis position. It may also include a prism or any other component adapted to provide prism power to the eyes of the subject. The resulting optical components are schematically represented in the figure by the lenses 11A, 12A( Figures 1 to 4 , Figures 10 to 12 ).

[0097] Alternatively or additionally, the optical component may include a set of non-deformable lenses with different optical powers, and a mechanical system capable of selecting some of these lenses and grouping them to form a set of lenses through which the subject can view. In the last case, in order to adjust the refractive power of the set of lenses, one or more lenses in the set are replaced with other lenses stored in the refractive test unit. Thus, the aforementioned optical axes correspond to the optical axes of the lenses placed in front of the eyes of the subject.

[0098] Each optical refractive element 11, 12 is intended to be placed in front of one of the eyes E1, E2 of the subject, close to this eye.

[0099] The relative position between the eyes E1, E2 of the subject and the corresponding optical components 11A, 12A of the refractive test unit 10 is quantified by the value of a parameter representing this relative position.

[0100] The value of the parameter representing the relative position between the eyes E1, E2 of the subject and the optical components 11A, 12A of the refractive test unit 10 can be measured, calculated, estimated or predetermined.

[0101] This parameter may be the distance measured between the optical components 11A, 12A of the optical refractive elements 11, 12 turned towards the eyes and the eyes E1, E2 placed in front of them, for example, the distance measured between the curvature vertices of the outer surfaces of the optical components 11A, 12A and the curvature vertices of the corneas of the eyes.

[0102] More precisely, the parameter may be the optical vertex distance, which is defined as the optical distance between the rear surface of the lens of the optical components 11A, 12A and the vertex of the cornea of the eye.

[0103] The measured distance can be a physical distance or an optical distance. The physical distance between two points corresponds to the distance measured along the straight line between these two points. The optical distance is measured along the optical path of light between these two points. The optical distance may or may not take into account the refractive index of the material in which the optical path lies. Thus, the optical distance between two points can correspond to the physical distance measured between these two points while following the optical path of light from one point to the other.

[0104] For example, it is equal to the sum of the physical distances measured between consecutive intersection points between the optical path and the surface of the optical component. When taking into account the refractive index of the material, the optical distance is equal to the physical distance multiplied by the refractive index. In practice, when light passes through air and / or different materials, the optical distance is equal to the sum of the physical distances traveled in air multiplied by the refractive index of air, and / or the physical distances traveled in the different materials, each physical distance multiplied by the sum of the refractive indices of the corresponding materials.

[0105] This parameter can also be defined, for example, as the optical distance between the center of eye rotation and the optical component, without taking into account the refractive index of the material through which the light travels.

[0106] This parameter can also be an angle.

[0107] The value of the parameter can be measured manually, for example, determined based on images of the subject's head and the optometry device, or predefined to be equal to an average value. The accessory device 2 can include a measuring device, as described in more detail below.

[0108] The optometry device 1 allows determination of the reference visual acuity correction power of the subject's eyes E1, E2 taking into account the refractive power provided by the refractive test unit 10 to the subject's eyes and the reference value of the parameter representing the relative position of the eyes and the optical component in the absence of the accessory device 2, as detailed below. The reference visual acuity correction power corresponds to the reference value of the visual acuity correction power required for the subject's eyes to achieve a target visual performance, which is determined using the reference value of the parameter representing the relative position of the subject's eyes E1, E2 and the optical components 11A, 12A of the refractive test unit 10.

[0109] The relative position of the subject's eyes and the optical components 11A, 12a of the optometry device 1 is controlled, for example, by using one or more position adjustment elements adapted to receive the subject's head.

[0110] The one or more position adjustment elements can belong to the refractive test unit 10. They can be designed to hold the subject's head in a given position relative to the refractive test unit 10.

[0111] The refractive test unit 10 includes, for example, a position adjustment element 15 adapted to receive the subject's forehead (seeFigure 5 ) Alternatively or additionally, the refractive test unit may include an element adapted to receive the chin of the subject.

[0112] Then, the position adjustment element can be used to obtain a predetermined value of the parameter representing the relative position of the eye with respect to the optical components 11A, 12A.

[0113] The position adjustment element is configured, for example, to ensure that the optical vertex distance between the eye of the subject and the optical components 11A, 12A of the optometry device 1 in the absence of the accessory device 2 is predetermined and equal to the target value of the optical vertex distance, which is equal to 12 mm.

[0114] The optometry device 2 will be described hereinafter in the case where each of the optical components 11A, 12A includes a lens with variable spherical power and a lens with variable cylindrical power and variable cylindrical axis position and optionally includes a prism, which is represented in the figure by the lenses with reference numerals 11A, 12A.

[0115] The optical components 11A, 12A have an overall spherical power S corresponding to the spherical refractive power, expressed in diopters. The optical components 11A, 12A have a cylindrical power C expressed in diopters and an orientation represented by an angle A. Each of the first and second refractive powers provided by the corresponding optical refractive elements 11, 12 can be characterized by the values of these three refractive power parameters S, C, and A.

[0116] The optical refractive elements 11, 12 are mounted on a common support 13 ( Figure 5 ) which extends between and above the optical refractive elements 11, 12 along a horizontal longitudinal axis H ( Figure 5 ).

[0117] This support 13 is connected to a global support structure 14 located on a table or the ground (partially presented in Figure 5 ).

[0118] Each of the optical refractive elements 11, 12 is mounted on the support 13 so as to be rotatable about a rotation axis V1, V2 perpendicular to the longitudinal axis H ( Figure 5 ). The mean plane MP of the first and second optical refractive elements 11, 12 passes through these axes V1, V2 ( Figure 5 ). This mobility of the optical refractive elements allows adjustment of the orientation of the optical axes OA1, OA2 of the optical components 11A, 12A. In particular, the optical components 11A, 12A can then be oriented taking into account the convergence of the eyes of the subject.

[0119] The optometry device 1 further includes a display unit 20 for providing one or more visual targets T1, T2. The display unit 20 is adapted to generate visual targets for the eyes of the subject, and the images I1, I2, I1', I2' of the displayed visual targets T1, T2 are visible through the refractive test unit 10 along the reference viewing direction OBS1. This reference viewing direction OBS1 extends along the optical axes OA1, OA2 ( Figure 1 ) of the optical components 11A, 12A of the refractive test elements 11, 12. The reference viewing direction OBS1 corresponds to the straight-ahead horizontal viewing direction. The images of the visual targets are visible through the exit apertures of the optical refractive elements 11, 12 of the optometry device 1.

[0120] The image of the visual target can be the visual target itself when the subject views it directly. It can also be a real or virtual image of the visual target through the optical setup of the optometry device 1 (and optionally, when the accessory device 2 is mounted on the optometry device 1, through the optical setup of the accessory device).

[0121] It preferably provides first and second visual targets T1, T2 for binocular testing. The images I1, I1' of the first visual target are transmitted along a first optical path to the first optical refractive element 11, and the images I2, I2' of the second visual target are transmitted along a second optical path to the second optical refractive element 12.

[0122] The image display unit 20 is thus configured to provide the image of the first visual target to the first eye E1 of the subject and, at the same time, to provide the image of the second visual target to the second eye E2 of the subject. The first visual target and the second visual target can be the same or can be different from each other.

[0123] The first eye E1 of the subject sees the image of the first visual target through the first optical refractive element 11, while the second eye E2 of the subject sees the image of the second visual target through the second optical refractive element 12.

[0124] The images I1', I2' of the visual targets T1, T2 provided to the two eyes E1, E2 are preferably configured such that fusion of the two visual targets by the subject's brain can occur ( Figure 17 ). Preferably, the two visual targets are stereoscopic images that provide at least a partially three-dimensional representation for the subject.

[0125] To achieve this, each visual target is configured to be accurately optically aligned with the corresponding eye of the subject.

[0126] Preferably, the first and second optical paths allow testing of the subject's eyes under distance vision conditions. The optical distances corresponding to the optical paths preferably exceed 1.5 meters, and even more preferably are between 3 meters and 5 meters.

[0127] The display unit 20 may include printed visual targets. In another embodiment, it may include one or more electronic devices, each electronic device including a screen and / or elements adapted to display visual targets. The screen is, for example, one of the following: an LED or OLED 20 screen, a silk screen with backlight, a display light projection screen with a micro video projector, an LCD screen or a TFT screen. Then, the display unit 20 includes an active screen that generates a light beam.

[0128] In another embodiment, the display unit includes a projector and projection elements adapted to project one or more visual targets. By projection is meant that each visual target is formed by a projection element (such as a lens).

[0129] Each visual target may be projected onto a passive screen or directly onto the retina of the subject's eye.

[0130] Each visual target T1, T2 includes, for example, one or more optotypes ( Figure 13 ). Each visual target may include any type of visual target suitable for testing the visual acuity of a subject known to those skilled in the art.

[0131] Preferably, the optometry device 1 further includes a control device 30. The control device 30 may include a processor and an interface, such as a screen. The control device is programmed to determine the reference visual acuity correction diopter of the subject's eyes based on a subjective test performed with the optometry device 1.

[0132] The control device 30 is programmed to determine the reference visual acuity correction diopter of the subject's eyes E1, E2 taking into account the refractive diopter provided by the refractive test unit 1 to the subject's eyes E1, E2. The control device may also take into account the reference value of the parameter representing the relative position of the eyes E1, E2 with respect to the optical components 11A, 12A in the absence of the accessory device 2.

[0133] Such a control device 30 is well known and will not be described in more detail here.

[0134] As described above, the optometry device 1 is configured to place the optical components 11A, 12A relative to the subject's eyes in a reference position. This reference position of the optical components relative to the subject's eyes corresponds to the reference value of the parameter representing the relative position of the eyes with respect to the optical components of the optometry device in the absence of the accessory device.

[0135] The subjective test is performed at the reference value of the parameter representing the relative position of the eyes with respect to the optical components of the optometry device to determine the reference visual acuity correction diopter.

[0136] The reference value d0 of the optical vertex distance without an accessory device corresponds to the optical distance between the vertex of the cornea of the subject's eye and the vertex of the rear surface of the optical elements 11A, 12A measured along the reference viewing direction OBS1( Figure 1 ). Here, it is equal to the physical horizontal distance measured when the eye is in the primary eye position (i.e., in the straight-ahead horizontal viewing direction).

[0137] The reference value d0 of the optical vertex distance used in the optometry device 1 without the accessory device 1 is typically equal to 12 mm.

[0138] The reference value d0 of the optical vertex distance can alternatively be between, for example, 11 mm and 15 mm.

[0139] In practice, the reference visual correction diopter is typically determined based on the test values of the refractive characteristics of the optical components used during the subjective test, corresponding to the optimal value for visual correction of the visual defect of the subject's eye.

[0140] The so-called visual correction diopter refers to the diopter that allows correction of the refractive error of the subject's eye, such as spherical power, cylindrical power and axis, prism power and axis, etc. Multiple values of visual correction diopter including multiple different diopter values can also be determined.

[0141] Without the accessory device 2, the optometry device 1 is mainly used for measurements performed along the straight-ahead horizontal viewing direction of the subject. Using this conventional optometry device for measurements along a downward viewing and / or convergent viewing direction would require a long positioning process to ensure accurate alignment of the subject's eye with the optical components of the optical refractive element. In addition, the position of the refractive test unit 10 and / or the subject's head would have to be modified.

[0142] To easily test the subject's visual acuity along the downward and / or convergent viewing directions, the accessory device 2 can be mounted on the optometry device 1 to obtain the optometry system 3.

[0143] The viewing direction of one of the subject's eyes corresponds to a straight line passing through at least two of the following points: the center of rotation of the eye, the center of the pupil of the eye, and the center of the visual target.

[0144] In Figure 2 , the accessory device 2 is shown as being coupled to the optometry device 1 as described above. The subject's eye is placed in front of the accessory device 2.

[0145] The accessory device 2 is used to cause the images I1, I2 of each visual target T1, T2 displayed by the display unit 20 of the optometry device 1 to move from the reference viewing direction OBS1 towards the inclined viewing directions OBS2, OBS3( Figure 2 and Figure 4)Deflection. The viewing direction is inclined downward ( Figure 2 ) and / or directed towards the other eye (convergence) ( Figure 4 ) and oriented.

[0146] The typical far vision distance is typically between 1.5 meters and infinity, where the straight-ahead horizontal viewing direction corresponds to a reference angle of 0°. The typical far vision distance can be between 3 meters and 5 meters. The typical mid vision distance is typically between 50 cm and 150 cm, with a downward viewing direction of approximately 15°. The typical near vision distance is typically between 25 cm and 50 cm, with a downward viewing direction of approximately 30°.

[0147] The inclined viewing direction OBS2 is, for example, oriented at a downward angle A1 between 15° and 45°, preferably equal to 30°, with respect to the reference viewing direction OBS1. This downward angle is measured in the vertical plane containing this reference viewing direction OBS1 ( Figure 2 ). The reference viewing direction OBS1 typically corresponds to the straight-ahead horizontal viewing direction. The inclined viewing direction OBS2 thus corresponds to a downward near vision viewing.

[0148] The inclined viewing direction OBS3 can also be oriented at a convergence angle A2 between 2° and 15° with respect to the reference viewing direction OBS1. This convergence angle is measured in the horizontal plane containing the reference viewing direction OBS1 ( Figure 4 ). The inclined viewing direction OBS2 thus corresponds to a convergent vision viewing.

[0149] According to the present invention, the optometry device 1 can be used together with the accessory device 2 to test the eyes of a subject as follows:

[0150] - When the subject observes the images I1, I2 of one or more visual targets T1, T2 displayed by the display unit 20 of the optometry device 1 along the reference viewing direction OBS1, a visual test is performed under far vision conditions, and the images are not deflected by the accessory device 2.

[0151] - Use the accessory device 2 to deflect the images I1, I2 of the visual targets T1, T2 towards the inclined viewing directions OBS2, OBS3.

[0152] - When the subject observes the images I1, I2 of the visual targets displayed by the display unit of the optometry device along the inclined viewing directions OBS2, OBS3, a visual test is performed under near or mid vision conditions, and the images are deflected by the accessory device. The refractive test unit 10 is not moved between performing the visual test under far vision conditions and performing the visual test under near or mid vision conditions.

[0153] The visual test is a subjective refractive test as described above. The visual perception of a visual target is evaluated by asking the subject to describe his perception of the visual target, by stating whether the visual target is seen, or by whether the subject can identify a visual symbol (such as a letter). The visual perception can also be evaluated, for example, by determining the latency required for the subject to identify the visual symbol. The evaluation of the visual perception can be accomplished by any method known to those skilled in the art.

[0154] Furthermore, the optical power of the lens in the optometric device and / or the visual target is changed according to the response of the subject during the evaluation step.

[0155] In the method, a distance vision test can be performed before or after the visual test under near vision or intermediate vision conditions. Preferably, the distance vision test is performed beforehand.

[0156] For this purpose, the accessory device 2 includes an optical part 40. The optical part 40 is configured to be mounted on the refractive test unit 10 of the optometric device.

[0157] The optical part 40 includes one or more optical systems 41, 42, which are configured to deflect the image of the visual target generated by the optometric device 1 from the reference viewing direction OBS1 towards the inclined viewing directions OBS2, OBS3.

[0158] When the optical part 40 is mounted on the refractive test unit 10 of the optometric device 1, the inclined viewing directions OBS2, OBS3 define a non-zero angle with the reference viewing direction OBS1. In other words, the one or more optical systems 41, 42 are configured to deflect the light beam leaving the optometric device 1 from the reference viewing direction OBS1 towards the inclined viewing directions OBS2, OBS3.

[0159] Since the optometric device 1 of this example is configured for binocular measurement, the refractive test unit 10 of the optometric device 1 has two optical refractive elements 11, 12 for providing different refractive powers to the two eyes of the subject. Therefore, the optical part 40 of the accessory device 2 includes two optical systems 41, 42 here, and each optical system 41, 42 is configured to be placed in front of one of the two optical refractive elements 11, 12 of the optometric device 1, thereby allowing the eyes of the subject to be tested under binocular vision.

[0160] Each optical system 41, 42 includes one or more optical elements 411, 412, 421, 422.

[0161] In Figures 2 to 12 the example shown, each optical system 41, 42 includes two optical elements 411, 412, 421, 422.

[0162] Each of the optical elements 411, 412, 421, 422 includes, for example, a reflective or semi-reflective surface.

[0163] In the appended Figures 2 to 12 In the example shown, these two reflective surfaces belong to two mirrors. In other embodiments of the present invention, the reflective surface may belong to a prism, a semi-reflective vane, a spherical mirror, an aspherical mirror, or any suitable optical element known to those skilled in the art.

[0164] The first optical elements 411, 412 among the optical elements 411, 412, 421, 422 are configured to be placed at an effective position in front of one of the exit holes of the optometry device 1 to deflect the visual target and transmit it to the second optical elements 421, 422 among the two optical elements 411, 412, 421, 422, and the second optical elements 421, 422 are configured to deflect the image of the visual target along the inclined viewing directions OBS2, OBS3.

[0165] In the example described below, each of the optical systems 41, 42 includes first and second optical elements 411, 412, 421, 422. In a variant, the optical elements may include other optical elements positioned between the first optical element and the second optical element.

[0166] On the one hand Figure 2 And on the other hand Figure 4 Two different internal arrangements of the optical portion 40 of the accessory device 2 are shown.

[0167] Figure 2 The internal arrangement of shows a first relative position of the first and second optical elements 411, 412, 421, 422. In this first relative position, the two planar mirrors corresponding to the two optical elements 411, 412, 421, 422 are placed partially one above the other in the vertical direction and at least partially face each other.

[0168] As Figure 2 shown, the first mirrors 411, 421 of the accessory device 2 are adapted to be inclined relative to the reference viewing direction OBS1. Compared with the vertical plane perpendicular to the reference viewing direction OBS1, the first mirrors 411, 421 can be inclined at an inclination angle around a horizontal axis perpendicular to the reference viewing direction OBS1 towards the second mirrors 412, 422. The second mirrors 412, 422 are placed below the first mirrors. In the case where the first and second optical elements are in the first relative position, the inclined viewing direction OBS2 corresponds to the downward gaze direction of the subject's eyes.

[0169] Figure 4The internal arrangement shows a second relative position of the first and second optical elements 411, 412, 421, 422. In this second relative position, the two mirrors corresponding to the two optical elements 411, 412, 421, 422 are placed side by side along the horizontal direction and partially face each other.

[0170] As Figure 4 shown, the first mirrors 411, 421 of the accessory device 2 are adapted to be tilted relative to the reference viewing direction OBS1. Compared with the vertical plane perpendicular to the reference viewing direction OBS1, the first mirrors 411, 421 can be tilted at an inclination angle around the vertical axis perpendicular to the reference viewing direction OBS1 towards the second mirrors 412, 422. The second mirrors 412, 422 are placed beside the first mirrors, on the side closer to the other eye. In the case where the first and second optical elements are in the second relative position, the tilted viewing direction corresponds to the convergent fixation direction of the subject's eyes.

[0171] The above internal arrangement can be combined such that the tilted viewing direction is both downward and convergent.

[0172] It should be noted that the convergent viewing direction can be obtained at least in part by rotating the refractive test elements 11, 12 of the optometry device 1 around their rotation axes V1, V2. The optical system of the accessory device 2 can then help to adjust the distance between the optical components of the optometry device to the pupil distance of the subject's eyes. This is particularly useful for pupil distances smaller than the average pupil distance.

[0173] This situation is shown in Figure 4 where the pupil distance between the subject's eyes is smaller than the distance between the optical axes OA1, OA2 of the optical components 11A, 12A of the optometry device 1. The accessory device 2 allows a subjective test to be performed on eyes with such a pupil distance.

[0174] This is also useful for accessory devices that introduce a greater distance variation between the eyes and the corresponding optical components.

[0175] The ratio between the convergence introduced by the accessory device 2 and the convergence introduced by the optometry device 1 can depend on the pupil distance of the subject: when the pupil distance increases (in other words, for a person with a higher pupil distance), the optometry device introduces an increasing part of the convergence.

[0176] When the pupil distance of the subject decreases (in other words, for a person with a lower pupil distance), the part of the convergence introduced by the optometry device decreases. Using both the optometry device 1 and the accessory device 2 to obtain the convergent viewing direction also allows the distance between the virtual images of the visual targets to be changed without modifying the configuration of the optical system of the accessory device.

[0177] Then, the optometry system 3 of the present invention can be used for any pupil distance value, for any distance between the eye and the optical components of the optometry device, and for any distance between the eye and the virtual image of the visual target.

[0178] Preferably, the size of the optical elements of the accessory device 2 is adjusted so as not to limit the field of view of the optometry device.

[0179] To ensure that the field of view of the subject's eye is not limited by the mirror, the basic geometric optics of the mirror is applied, as Figure 2 schematically shown above and explained below.

[0180] Figure 2 、 Figure 4 and Figure 8 show the optical path of the light rays emitted by the display unit 20 represented by full straight lines, which starts from the visual targets T1, T2 ( Figure 4 ) or from the optical components 11A, 12A of the optometry device 1 and reaches the subject's eye E1.

[0181] Figure 2 、 Figure 4 and Figure 8 show the optical path of the light when the accessory device 2 is in a configuration where the light is deflected by the first optical components 411, 421 of the accessory device 2 from the reference viewing direction OBS1. The optical path of the light initially extends along the optical axis OA1 of the optical component 11A of the optometry device 1, which is aligned with the reference viewing direction OBS1. The light is reflected by the first mirror 411 towards the second mirror 421 and is reflected by the second mirror 421 towards the pupil center of the subject's eye along the final viewing directions OBS2, OBS3 ( Figure 2 、 Figure 4 and Figure 8 ).

[0182] In a general manner, the rotation center CRO1 of the eye E1 can advantageously be aligned with the reference viewing direction OBS1, and preferably with both the reference viewing direction OBS1 and the tilted viewing directions OBS2, OBS3, to ensure that, without changing the position of the subject's eye, the image of the visual target viewed along the reference viewing direction OBS1 can be switched to the image of the visual target viewed along the tilted viewing directions OBS2, OBS3 simply by removing the first mirror 411 from the reference viewing direction OBS1.

[0183] Figure 2 、 Figure 4 and Figure 8A schematic diagram showing an equivalent straight optical path represented by a dashed line is shown. This equivalent straight optical path extends along the inclined viewing directions OBS2 and OBS3. The virtual positions VL of the optical component 11A along this equivalent straight optical path are shown as dashed lines. This virtual position VL is obtained by unfolding the optical path between the optical component and the subject's eye to trace the equivalent straight optical path (represented by a dashed line).

[0184] The optical vertex distances d2 and d3 between the eye and the virtual position VL are equal to the optical vertex distance d3 between the eye and the optical component 11A: For example, it is the sum of the optical distances along the optical path from the vertex of the cornea of the eye to the second mirror 412, the optical distance along the optical path between the second mirror 412 and the first mirror 411, and the optical distance along the optical path between the first mirror 411 and the vertex of the surface of the optical component 11A oriented towards the eye.

[0185] This unfolding and presentation of the optical path in the optometry device 1 and the accessory device 2 allows the visualization of the optical vertex distance in the downward or convergent gaze direction configuration of the optometry system 3, which corresponds to the value of the said parameter of the accessory device 2 in the downward or convergent gaze direction.

[0186] It also allows checking that the field of view is limited by the exit aperture of the optometry device 1 rather than by the mirror. Figure 2 and Figure 4 The dotted lines show that the entire range of the optical component is visible through the accessory device 2.

[0187] Advantageously, in the embodiments shown in Figure 2 , Figure 3 and Figures 5 to 8 , the first optical elements 411 and 412 are movable between the effective position and the second retracted position. At the effective position, the first optical elements are placed in front of the exit aperture of the optometry device 1 in the reference viewing direction OBS1 of the optometry device 1, in other words, in front of the optical components 11A and 12A ( Figure 2 and Figure 8 ). At the second retracted position, the first optical elements are placed outside the reference viewing direction OBS1 ( Figure 3 and Figure 7 ).

[0188] When the first optical elements 411 and 412 are in the effective position, the light beam leaving the optometry device is intercepted by the first optical elements 411 and 412 and deflected towards the second optical elements 421 and 422. The image of the visual target is visible to the subject's eye in the inclined viewing directions OBS2 and OBS3. Subjective tests can be performed in the near or intermediate vision conditions along the downward and / or convergent gaze directions.

[0189] When the first optical elements 411, 412 are in the second retracted position, the light beam leaving the optometric device is not deflected by the accessory device, and the image visual target is the eye E1 of the subject visible in the reference viewing direction OBS1. Figure 3 ) The subjective test can be performed along the straight-ahead horizontal viewing direction under far vision conditions.

[0190] This mobility of the first optical element allows the eyes of the subject to be tested in the downward viewing direction OBS2 and / or the convergent viewing direction OBS3 as well as in the straight-ahead horizontal viewing direction OBS1 without removing the accessory device 2 as a whole from the optometric device 1. In addition, the subjective test can be performed under far vision conditions and near or intermediate vision conditions without moving the optometric device 1.

[0191] Therefore, these two optical elements 411, 412, 421, 422 of each optical system 41, 42 are preferably arranged such that in use, the reference viewing direction OBS1 and the tilted viewing directions OBS2, OBS3 both pass through the centers of rotation CRO1, CRO2 of the eyes E1, E2 of the subject. Thus, the subjective test can be performed under far vision conditions and near or intermediate vision conditions without moving the refractive test unit of the optometric device or the head of the subject. This is made possible by considering a predetermined position of the head of the subject (e.g., controlled by the position adjustment element of the optometric device).

[0192] Alternatively, the accessory device can have a fixed optical element, such as a fixed mirror, which has no mobility. In this case, the accessory device can be completely removed from the optometric device 1 for using the optometric device along the straight-ahead horizontal viewing direction. In this case, the easily removable attachment means for the accessory device can ensure that the test is performed along the downward and / or convergent viewing and straight-ahead horizontal viewing without moving the optometric device 1.

[0193] In Figure 10 and Figure 11 In the first and second variants of the accessory device 2 of the present invention schematically presented above, these two first optical elements 411, 412 of these two optical systems 41, 42 of the accessory device 2 extend in the same first plane, and these two second optical elements 421, 422 of these two optical systems 41, 42 of the accessory device 2 extend in the same second plane.

[0194] The relative positions and / or orientations of the two first optical elements 411, 412 and the relative positions and / or orientations of the two second optical elements 421, 422 are fixed. This means that when the first optical elements are movable as described above, these two first optical elements 411, 412 move together.

[0195] In particular, inFigure 10 In the first variant presented above, the reflective or semi-reflective surfaces of these two first optical elements 411, 412 may belong to a single piece, for example, to a first single mirror. The reflective or semi-reflective surfaces of these two second optical elements 421, 422 may also belong to a single piece, for example, to a second single mirror. The first single mirror forming these two first optical elements 411, 412 may be movable between the first position and the second retracted position as described above.

[0196] This ensures that the optical path of light is the same for both eyes and allows for the accurate alignment of the optical components of the optometry device, the optical systems of the accessory devices, and the eyes of the subject. The image of each visual target is seen by the corresponding eye, and the fusion of these two images can occur without any alignment problems.

[0197] In practice, the alignment error of the mirror should be less than 1°, preferably less than 1', to ensure the comfortable fusion of the visual targets and thus ensure accurate binocular vision of the visual targets.

[0198] In Figure 11 In the second variant presented above, the optical systems 41, 41 are formed by different first and second optical elements. However, the reflective or semi-reflective surfaces of these two first optical elements 411, 412 of the optical systems 41, 42 are aligned in the same plane. They may include, for example, two coplanar mirrors. The reflective or semi-reflective surfaces of these two second optical elements 421, 422 may also be aligned in another plane, for example, belonging to two different coplanar mirrors.

[0199] The relative position and orientation of these two optical systems 41, 42 as a whole are fixed. The position and / or orientation of these two first optical elements on the one hand and the position and / or orientation of these two second optical elements on the other hand are fixed or can only be changed jointly.

[0200] In Figure 12 In the third variant shown, the position and / or orientation of each optical system 41, 42 is adjusted such that the optical systems 41, 42 remain aligned with the corresponding optical components 11A, 12A of the optometry device 1. The position and / or orientation of each optical system 41, 42 is adjustable independently of the position and / or orientation of the other optical system 41, 42.

[0201] In addition to the optional mobility of the above-mentioned first optical elements, the relative position and orientation of the first and second optical elements of each optical system 41, 42 are fixed.

[0202] In particular, each optical system 41, 42 can rotate about the rotation axes X1, X2 ( Figure 12)。These rotation axes X1, X2 are configured to be parallel to the rotation axes V1, V2 of the optical refractive elements 11, 12 of the optometry device 11 when the accessory device 2 is attached to the optometry device 1.

[0203] In this case, when the optical systems 41, 42 are rotated to be aligned with the converging optical axes OA1, OA2 of the optical components of the optometry device 1, the accessory device preferably includes a software part that is programmed to symmetrically rotate the visual targets displayed for both eyes by the display unit 20 of the optometry device 1 to compensate for the rotation experienced by each image of the visual target, which is caused by the combination of rotations imposed by reflections on the optical elements of the optical system of the accessory device. This will be described in more detail below with reference to Figures 13 to 17 More specifically.

[0204] The accessory device 2 is placed between the exit holes of the optical refractive elements 11, 12 of the refractive test unit 10 of the optometry device 1 and the eyes of the subject. The presence of the accessory device 2 thus modifies the physical and / or optical distance between the eyes and the corresponding optical components 11A, 12A of the refractive test unit. This physical and / or optical distance typically increases. Therefore, the parameters representing the relative positions of the subject's eyes and the corresponding optical components 11A, 12A of the optical refractive elements 11, 12 of the optometry device 1 exhibit final values determined in the presence of the accessory device that are different from the reference values, and in particular higher than the reference values.

[0205] Figure 2 , Figure 4 and Figure 8 show the optical vertex distances d2, d3 when the first mirror is in the effective position in the presence of the accessory device.

[0206] Figure 3 and Figure 7 show the optical vertex distance d1 when the first mirror is in the retracted position in the presence of the accessory device.

[0207] The size and orientation of the optical elements of each optical system 41, 42 of the accessory device 2 can be adjusted such that the optical distance between the subject's eyes and the optical components 11A, 12A of the refractive test unit 10 of the optometry device 1 is minimized when the accessory device 2 is mounted on the optometry device 1.

[0208] In Figures 2 to 4 the example shown, the size and orientation of the two mirrors used as optical elements 411, 412, 421, 422 can be adjusted such that this optical distance is minimized.

[0209] In practice, the final value of the optical distance between the optical components 11A, 12A of the optometry device 1 and the eyes of the subject is, for example, between 20 mm and 80 mm, preferably approximately 50 mm.

[0210] Furthermore, the presence of the accessory device 2 can modify the relative position and / or orientation of the eyes E1, E2 of the subject and the image of the visual target seen by the subject's eyes.

[0211] The accessory device 2 can be attached to the optometry device 1 by any suitable means known to those skilled in the art, such as a threaded connection, gluing, or attachment to the housing of the optometry device by magnets or any other mechanical means.

[0212] The accessory device 2 can be removable or fixed from the optometry device 1. In the removable case, easily removable mounting means, such as snap-fit means, can be used.

[0213] Two embodiments of the accessory device 2 are presented respectively in Figures 5 to 8 and Figure 9 As Figures 5 to 9 shown, in each embodiment, the optical portion 40 of the accessory device 2 includes a housing 43 that is configured to be attached to the refractive test unit 10 of the optometry device 1.

[0214] Each optical system is housed in the housing 43.

[0215] In practice, the housing 43 is attached to the optometry device 1. Preferably, the housing is immovably attached to a fixed position on the optometry device 1.

[0216] The housing 43 herein includes two frames 43A, 43B having a substantially rectangular profile ( Figure 6 and Figure 9 ). Each frame 43A, 43B is attached to one of the refractive test elements 11, 12 ( Figure 5 and Figure 9 ).

[0217] In Figures 5 to 8 and Figure 9 's first and second embodiments, each frame 43A, 43B includes an end wall 44 that is configured to be placed against the optical refractive elements 11, 12 of the optometry device. The end wall includes holes 44A, 44B to allow light to enter the accessory device 2. Lateral walls 45 frame this end wall on three sides.

[0218] The lateral walls 45 of each frame 43A, 43B include two parallel side walls 451 that extend along the longitudinal axis L1 of the accessory device. The longitudinal axis is configured to be vertical when the accessory device 2 is in use.

[0219] The longitudinal axis L1 of the attachment device is configured to extend parallel to the rotational axes V1, V2 of the optical refractive elements 11, 12 of the optometric device 1.

[0220] The two frames 43A, 43B are joined by a horizontal bar extending perpendicular to the side walls.

[0221] The side walls 451 of each frame 43A, 43B are connected by a bottom wall 452 extending perpendicular to the side walls 451.

[0222] The inner surfaces of the bottom walls 452 of each frame 43A, 43B are inclined towards the subject about a transverse axis perpendicular to the longitudinal axis of the attachment device. These inner surfaces support the reflective surfaces of the second optical elements 412, 422 forming each optical system.

[0223] In both embodiments, the flap 46 extends from one frame to the other. It is mounted on the lateral walls of the frames about a rotational axis Y ( Figure 6 and Figure 9 ). The rotational axis Y is substantially horizontal. It is parallel to the two reflective surfaces 411, 412, 421, 422 of each optical system.

[0224] The flap 46 includes two coplanar elements of the flap, each mounted inside one of the two frames 43A. They are connected by a bridging portion 46B which includes a recess 46A at its front edge. The recess 46A is provided to allow the subject's nose to extend between the two frames ( Figure 6 and Figure 9 ).

[0225] The face of the flap 46 oriented towards the bottom wall 452 includes a single reflective surface extending across the flap, or two separate reflective surfaces placed corresponding to the bottom wall 452, thus forming the first optical elements 411, 421.

[0226] When the bridging portion 46B of the flap 46 abuts against the side walls of the frames 43A, 43B, the first optical elements 411, 421 are in the effective position ( Figure 5 , Figure 6 and Figure 9 ).

[0227] To place them in the retracted position, the flap 46 is pivoted upwards about the rotational axis Y and blocked in this pivoted position ( Figure 7 ).

[0228] An example of this embodiment corresponds to the situation presented in Figure 11 where the reflective surfaces of the first optical element and the reflective surfaces of the second optical element of the optical system are coplanar.

[0229] The accessory device 2 further includes two arms 47 presenting an L-shape for attaching the housing 43 to the optometric device 1. The arms 47 extend in a common average plane.

[0230] Each frame 43A, 43B is connected to one of the arms 47.

[0231] Each arm 47 includes a transverse end portion and a longitudinal portion extending along the longitudinal axis L1 of the accessory device 2. The transverse end portions of the arms 47 extend away from each other. Each of the transverse end portions includes a plate 48, the shape of which corresponds to the contour of the corresponding portion of the support 13 of the optical refractive elements 11, 12 of the optometric device 1. Each plate 48 includes magnets configured to interact with the corresponding portions of the supports 13 of the optical refractive elements 11, 12 of the optometric device 1 to attach the accessory device to the optometric device. In practice, the cover plate of the support 13 is removed and replaced with the plate 48 to attach the accessory device.

[0232] In Figure 9 In the second embodiment of the accessory device shown, the accessory device 2 further includes an image capture device 50 for capturing a contour image of the subject's eye.

[0233] The image capture device 50 includes sensors 56, such as cameras, each configured to capture a contour image of one of the subject's eyes. Each sensor 56 is part of a printed circuit board 55 powered by an electrical conductor 57. Each printed circuit board 55 is supported by a base 51. The base 51 includes a first branch extending from the side walls of the frames 43A, 43B of the housing 43 of the optical part 40 of the accessory device 2, parallel to the common average plane of the arms 47. The base 51 further includes a second branch 52 extending perpendicular to the first branch 51. The free end of the second branch 52 forms a receiving plate 54 for receiving the printed circuit board 55. Thus, the two printed circuit boards extend parallel to each other and face each other.

[0234] Advantageously, the accessory device 2 further includes a determination tool 31 configured to determine the visual correction power of the subject's eye taking into account the refractive power provided by the refractive test unit 10 during the subjective refractive test and the final value of the parameter representing the relative position of the eye with respect to the optical components 11A, 12A of the optometric device 1 in the presence of the accessory device 2.

[0235] The determination tool provides the visual correction power of the subject's eye taking into account the new optical path of light through the accessory device. Then, the accurate value of the visual correction power can be determined by a system including the optometric device and the accessory device.

[0236] In practice, the determination tool 31 includes, for example, a software part that is programmed to calculate the vision correction diopter based on the final value of the parameter representing the relative position of the subject's eyes with respect to the optical components 11A, 12A of the optometry device 1 determined in the presence of the accessory device 2.

[0237] The determination tool may be configured to be implemented by the control device 30 of the optometry device. The determination tool 31 is presented as part of the control device 30 at Figure 2 and Figure 3 above.

[0238] The determination tool may be software uploaded in the control device. In this case, the determination tool may calculate the vision correction diopter based on the refractive measurement performed in the presence of the accessory.

[0239] The determination tool may also calculate the vision correction diopter based on the reference vision correction diopter and the final value of the parameter representing the relative position of the subject's eyes with respect to the optical components 11A, 12A of the optometry device 1. The determination tool may also consider the reference value of the parameter representing the relative position of the subject's eyes with respect to the optical components 11A, 12A of the optometry device 1.

[0240] The accessory device 2 may also include an adjustment tool 32 that adjusts the position and / or orientation of each visual target T1, T2 displayed by the display unit 20 based on the inclination of the inclined viewing directions OBS2, OBS3, and / or adjusts the refractive diopter of the optical components 11A, 12A of the optometry device 1 based on the value of the parameter representing the relative position of the images of the visual target T1, T2 units with respect to the subject's eyes E1, E2.

[0241] The adjustment tool 32 may include software, which may also be implemented by the control device 30 of the optometry device 1.

[0242] In a variant, the determination tool and / or the adjustment tool may be implemented by one or more processors different from the processor of the control device of the optometry device.

[0243] The vision correction diopter VCP determined by the determination tool 31 takes into account the refractive diopter of the optical components 11A, 12A of the optometry device 1 used during the subjective test and the final value of the parameter representing the relative distance between the eyes and the optical components when performing the subjective test using the optometry system 3 including the accessory device 2 under far vision conditions ( Figure 3 ) or near vision or intermediate vision conditions ( Figure 2 and Figure 4 ).

[0244] In an embodiment, the determination tool is programmed to determine a reference visual correction power VCP(d0) for a reference value d0 of the vertex distance based on the refractive power SPH(di) provided by the optical components 11A, 12A when placed at a working optical vertex distance equal to di using the following basic formula:

[0245]

[0246] where

[0247] - the working optical vertex distance di is in millimeters and here corresponds to the final value of a parameter representing the relative position between the eye and the optical components of the optometric device; in the example presented in the figure, di can be equal to d1, d2 or d3;

[0248] - Pobj is in diopters and is the reciprocal of the physical distance between the vertex of the face of the optical component 11A oriented towards the subject's eye at its virtual position VL and the image I1 of the visual target T1 seen by the eye through the optical components of the optometry, for example equal to 2.5D at 40 cm,

[0249] - SPH(di), in diopters, is the refractive spherical power of the optical component during the subjective test when the subject's eye is placed at the working optical vertex distance di, the refractive power of the optical component being calibrated for an object at infinity, and

[0250] - d0 is the reference value of the optical vertex distance corresponding to the recommended optical vertex distance in the absence of the attachment, in millimeters.

[0251] The reference value of the optical vertex distance is typically equal to 12 mm and is similar to the average distance between the eye and the ophthalmic lens worn by the subject.

[0252] In the example shown in the figure, when the first mirror is in the retracted position ( Figure 3 ), the working optical vertex distance di is equal to d1, and when the first mirror is in the effective position ( Figure 2 and Figure 4 ), it is equal to d2 or d3.

[0253] In the retracted and effective positions of the first mirror, the optical vertex distances d1, d2, d3 can be measured, for example derived from the contour image of the eye viewed through the optical system 3, and in each of the retracted and effective positions of the first mirror, the internal geometry of the system is predetermined, fixed and known.

[0254] In short, for myopic eyes, the optical components 11A, 12A of the optometry device 1 include diverging lenses. If the diverging lenses of the optometry device 1 are at a working optical vertex distance di from the eyes E1, E2 of the subject, and this working optical vertex distance is greater than the reference value d0 of the optical vertex distance s, then compared with the focal length of the diverging lens that provides appropriate visual correction at the reference value of the optical vertex distance, the diverging lens that provides appropriate visual correction at the working optical vertex di and is determined by subjective refraction testing exhibits a reduced focal length.

[0255] Then, the absolute power value of the diverging lens that provides appropriate visual correction at the working optical vertex distance di is higher than the absolute power value of the diverging lens that provides appropriate visual correction at the reference value of the optical vertex distance.

[0256] For hyperopic eyes, the optical components of the optometry device include converging lenses. If the converging lenses of the optometry device are at a working optical vertex distance di from the eyes of the subject, and this working optical vertex distance is greater than the reference value of the optical vertex distance, for example, equal to 12 mm, then compared with the focal length of the converging lens that provides appropriate visual correction at the reference value of the optical vertex distance, the converging lens that provides appropriate visual correction at the working optical vertex distance di exhibits a longer focal length. Then, the absolute power value of the converging lens that provides appropriate visual correction at the working optical vertex distance di is lower than the absolute power value of the converging lens that provides appropriate visual correction at the reference value of the optical vertex distance.

[0257] The reference visual correction power of the subject's eyes corresponds to the power of the diverging and / or converging lenses used in the optometry device without the accessory device, as determined by subjective refraction testing at the reference value d0 of the optical vertex distance.

[0258] In the case of astigmatism, the above basic formula is applied to the first power value P1 equal to the spherical power SPH and the second power value P2 equal to the spherical power SPH plus the cylindrical power CYL: P2 = SPH + CYL.

[0259] This formula is only correct for objects at infinity because the optometry device is using optical components with powers calibrated for infinity, corresponding to Pobj = 0D in the above formula. At any other distance, this formula is only exact in the thin lens approximation.

[0260] The optometry device 1 is programmed to provide a reference visual correction power corresponding to observing a visual target placed at infinity from the subject's eyes in the absence of the accessory device.

[0261] Therefore, the refractive power provided or displayed by the optometry device 1 in the absence of the accessory device 2 generally corresponds to the back vertex power calculated for a visual target at infinity.

[0262] In an embodiment of the accessory of the present invention, the determination tool 31 is configured to determine the vision correction diopter based on the value of a parameter representing the relative position of an image representing a visual target with respect to the eyes of the subject. The determination tool is also advantageously configured to take into account the exact geometry and / or optical characteristics of the optical components 11A, 12A of the optometric device 1.

[0263] In fact, more accurate calculations can be performed by ray tracing and an exact description of the geometry of the optical system, as described below in an example of an embodiment of the present invention in a subjective test performed with the optometric system of the present invention under near vision conditions.

[0264] The optical vertex distance between the eye and the optical components 11A, 12A of the optometric system 3 is equal to d2 ( Figure 2 ) or d3 ( Figure 4 ) and takes into account the optical path of the light passing through the accessory device 2. The distance between the rear surface of the optical component 11A placed at the virtual position VL and the virtual image of the visual target is typically 40 cm. The refractive diopter provided by the optometric device corresponds to the back vertex power calibrated for a visual target at infinity.

[0265] Then, the determination tool is programmed to simulate the optical components 11A, 12A of the optometric device 1 that provide the refractive diopter, use the ray tracing method to calculate the image of the virtual visual target passing through the optical components 11A, 12A, and calculate the reference vision correction diopter based on the value of a parameter representing the relative position of the subject's eyes with respect to the optical components 11A, 12A of the optometric device (here, the optical vertex distances d2, d3 and the reference value d0 of the optical vertex distance).

[0266] To simplify the ray tracing calculations, the corneal vertex and the eye rotation center of the eye E1 are virtually positioned on the reference observation direction OBS1 of the optical component 11A of the optometric device 1, at an optical vertex distance d2 from the rear surface of the optical component 11A, and the object point is placed on the reference observation direction OBS1, at a distance from the rear surface of the optical component 11A equal to the distance between the rear surface of the virtual position VL of the optical component 11A oriented towards the eye E1 and the center of the virtual image I1 of the visual target T1 seen through the accessory device 2.

[0267] Figure 18 The elements of this simulation are schematically shown. The virtual position of the eye E1 is defined by the position of the vertex of its cornea C1 and its rotation center CRO1.

[0268] The points J and J' represent two different positions of the vertex of the rear surface of the optical component 11A oriented towards the eye E1. The point J represents the actual position of the vertex of the rear surface of the optical component 11A oriented towards the eye E1 when the optical vertex distance is equal to d2, d3, while the point J' represents the theoretical position of the vertex of the rear surface of the optical component 11A oriented towards the eye E1 when the optical vertex distance is equal to the reference value of the optical vertex distance. The optical vertex distance is hereby defined as the optical distance between the vertex of the cornea C1 of the eye E1 and the vertex (marked as J or J') of the rear surface of the optical component 11A of the optometric device.

[0269] The actual optical vertex distances d2, d3 between the eye E1 and the optical component 11A of the optometric device are greater than the reference value.

[0270] The points M and M' in the reference viewing direction OBS1 represent two corresponding actual and theoretical object points. The distances MJ, M'J' are fixed and remain equal to the distance between the rear surface of the optical component 11A oriented towards the eye E1 at the virtual position VL and the virtual image I1 of the visual target T1 seen through the Figure 4 accessory device in it.

[0271] The refractive power obtained from the optometric device 1 at the end of the refractive test is used to derive the characteristics of the optical model corresponding to the optical component 11A or the characteristics of the optometric device 1 used without the accessory device 2. If the optical component 11A includes a continuously deformable lens, the shape of the lens can be optimized taking into account the refractive power provided by the optometric device 1 and the visual target placed at infinity.

[0272] The sagittal focus S F corresponding to the point M F and the tangential focus T

[0273] are calculated by ray tracing using an optical model that reflects the characteristics of the optical component 11A and is derived from the refractive power of the optometric device 1 obtained at the end of the refractive test. F Then, the determination tool calculates: the sagittal focus S F the distance JS F between and the tangential focus T F , and the actual position J of the optical component 11A.

[0274] Then, based on the distance M'J' between the object point and the rear surface of the optical component of the optometric device at its theoretical positions M', J' (where M'J' = MJ) and the distances J'S F J'T F, calculate the reference visual acuity correction power (VCP(d0)) corresponding to the reference value d0 of the optical vertex distance.

[0275] For example, calculate the spherical equivalent reference visual acuity correction power VCP and the astigmatism VCAST using the following formula:

[0276] VCP(d0) = 1 / M'J' + 0.5 * (1 / J'S F + 1 / J'T F )

[0277] VCAST(d0) = 1 / J'S F - 1 / J'T F

[0278] where

[0279] J'S F = J'S F + di - d0

[0280] J'T F = J'T F + di - d0

[0281] where di = d2 or d3.

[0282] This formula can be used to determine the visual acuity correction power, which is spherical power, equivalent spherical power, cylindrical power, or astigmatism.

[0283] In the case of considering the virtual image of the visual target, the above distances MJ, M'J', J'S F and J'T F are signed algebraic values.

[0284] In an embodiment, the distances between the eyes E1, E2 of the subject and the optical components 11A, 12A of the optometry device 1, particularly the optical vertex distance, are measured using an image capture device (such as the image capture device described above with reference Figure 9 ). The camera is positioned such that it is configured to capture an image showing the eyes of the subject. It also includes means for determining the distance between the camera and the optical components of the optometry device.

[0285] Alternatively, the camera is positioned such that it is configured to capture an image showing the eyes of the subject and the optical components of the optometry device.

[0286] In another variant, the camera includes a time-of-flight camera.

[0287] Alternatively, the distance between the eyes of the subject and the optical system of the accessory device 2 is calculated by adding the total optical path length of the accessory device and the distance between the accessory device and the optometry device.

[0288] In another example of an embodiment of the present invention, the determination tool may include a database that includes data related to the refractive correction power of the subject's eye, the data being associated with the value of the parameter that represents the relative position of the subject's eye and the optical components of the refractometer in the presence of the accessory device. The database may also include data related to the refractive correction power of the subject's eye, the data being associated with the refractive power of the optical components of the refractometer, in particular the refractive power obtained in the last step of the subjective test (corresponding to the optimal value for the visual correction of the visual defect of the subject's eye).

[0289] The database may include tables or graphs. In this case, taking into account this data, the refractive correction power suitable for the subject's eye can be read from the database. Examples of such databases are given in Tables 1 to 3 below.

[0290] For an image of a visual target located 40 cm from the rear surface of the optical component, Table 1 below shows the refractive correction power corrected to suit the target distance of 12 mm between the eye and the ophthalmic lens, which is corrected based on the values of the spherical refractive power (Rxsph) of the optical components 11A, 12A obtained in the last step of the subjective test under near vision conditions and the true optical vertex distance (d2) between the cornea of the eye and the optical components of the refractometer.

[0291] Table 1

[0292]

[0293]

[0294] Table 2 below shows the difference between the refractive correction power determined as such and the refractive correction power calculated without correction by a prior art refractometer 1.

[0295] Table 2

[0296]

[0297]

[0298] Table 3 shows the estimation of the astigmatism difference (Ast_diff) for different values of the cylindrical refractive power (Rx_cyl) of the optical components 11A, 12A of the refractometer 1 obtained in the last step of the subjective test, for an object located 40 cm from the rear surface of the optical components 11A, 12A of the refractometer 1 and a distance of 12 mm between the eye and the ophthalmic lens.

[0299] Table 3

[0300] Rx_cyl(D) Ast_diff(D) 0 0.03 1 -0.06 2 -0.13 3 -0.19 4 -0.26

[0301] The presence of the accessory device 2 can also modify the relative position of the image of the visual target seen by the subject's eyes with respect to the subject's eyes. In particular, the introduced deviation for providing a convergent view means that virtual images I1, I2 of the visual targets T1, T2 are perceived at a viewing near distance from the subject's eyes E1, E2( Figure 4 ).

[0302] In order to also generate the need for accommodation related to the near position of the virtual image of the visual target, the refractive power of the optical components 11A, 12A of the optometry device 1 can be adjusted by a value Pscreen - Pobj, where Pscreen is the actual proximity of the displayed visual target (for a 5 m distance, close to 0 or 0.2 D...), and Pobj is the target proximity of the virtual image of the visual target (2.5 D, i.e., 40 cm, near). Proximity is equal to the reciprocal of the distance.

[0303] The adjustment tool 32 of the accessory device 2 can then include a software part that is programmed to adjust the refractive power of the optical components 11A, 12A of the optometry device 1.

[0304] The adjustment tool 32 of the accessory device 2 can also include a software part that is programmed to adjust the position and / or orientation of each visual target T1, T2 displayed by the display unit 20 based on the tilt angles of the tilt observation directions OBS2, OBS3, as described above.

[0305] Determining this adjustment is to ensure that the images I1', I2' of the visual targets T1, T2 seen by the subject's eyes assume a predetermined position and / or orientation.

[0306] In particular, each set of first optical elements 411, 412 and second optical elements 421, 422 can rotate about rotation axes X1, X2( Figure 12 ). These rotation axes X1, X2 are configured to be parallel to the rotation axes V1, V2 of the optical refractive elements 11, 12 of the optometry device 1 when the accessory device 2 is attached to the optometry device 1.

[0307] Thus, when the optical refractive elements 11, 12 of the optometry device 1 rotate about their rotation axes V1, V2, the corresponding set of first and second optical elements can be rotated to maintain the accurate alignment of all optical components. This is especially the case when the accessory device is used to provide a tilt observation direction corresponding to a convergent gaze direction.

[0308] In the case where the positions and / or orientations of the optical systems are adjusted independently of each other, as Figure 12As shown, the position and orientation of the visual targets displayed by the display unit 20 must be adapted to the orientation of the subject's gaze direction, as described below. In fact, if the first and second optical elements 411, 422, 421, 422 of the two optical systems of the two eyes are not in the same plane, the visual targets seen by each eye of the subject will rotate around the tilted viewing direction. Preferably, in this case, the adjustment tool 32 of the accessory device includes a software part that is programmed to rotate the visual targets of each eye symmetrically to compensate for the gyration experienced by each image, which is caused by the combination of the rotations implied by the mirrors of each optical system 41, 42.

[0309] Figure 13 An example of the visual targets T1, T2 displayed by the display unit 20 of the optometry device without any adjustment is shown.

[0310] Figure 14 Schematically presents the two images I1, I2 of the visual targets T1, T2 seen by the two eyes of the subject when viewing through the accessory device 2 and the optometry device 1 in the Figure 13 configured state.

[0311] These two images I1, I2 of the visual targets T1, T2 can be generated based on a single image or two identical or different images. Each of them is directed to one eye of the subject. Due to the rotation of the optical elements of the accessory device 2, the images I1, I2 of the visual targets T1, T2 rotate. Figure 14 Schematically shows the images I1, I2 of the visual targets seen by each eye of the subject.

[0312] Figure 15 Shows the superposition of these two images I1, I2 of the visual targets seen by the subject under binocular vision. The subject will not be able to see a clear image, as Figure 15 presented: These two images I1, I2 of the visual targets T1, T2 cannot be fused because they cannot be superimposed.

[0313] Then, the position and orientation of the visual targets T1, T2 generated by the position and orientation of the display unit 20 should be adjusted so that the two images I1', I2' of the visual targets reflected by the accessory device 2 are accurately superimposed.

[0314] Figure 16 Shows the corrected visual targets T1', T2' displayed by the display device.

[0315] Each corrected visual target T1', T2' is oriented in such a way that the images I1', I2' of the corrected visual targets are accurately superimposed by the subject's binocular vision, as Figure 17 shown.

[0316] In practice, the correction consists in rotating the visual targets T1, T2 initially displayed for each eye by a correction angle value Acorr. The correction angle value Acorr is calculated based on the convergence angle value A2 and the downward angle value A1 of the tilted viewing direction obtained by means of the accessory device 2 according to the following formula:

[0317] Acorr = A2 * sin(A1).

[0318] The use of the accessory device 2 together with the optometric device 1 allows the gaze direction of the subject's eyes to be moved downwards without changing the position of the optometric device 1, in particular the refractive test unit 10.

[0319] This solution has many advantages:

[0320] - When switching from the straight-ahead gaze direction for performing a distance refractive test with the optometric device 1 to the downward gaze direction for performing a near refractive test, it is not necessary to modify the position or orientation of the optometric device, nor the position and / or orientation of the subject's head.

[0321] - The accessory device is a simple and light additional device.

[0322] - The accessory device can be configured to be used with any type of optometric device.

[0323] - The use of the accessory device allows the optometric device to perform a near test with comfortable ergonomics, without relying on the subject's cheekbones when performing the near test.

[0324] The accessory device 2 can also be used to produce convergence between two eye gaze directions. This solution has the following advantages:

[0325] - When switching from a distance refractive test to a near refractive test, it is not necessary to adjust the relative position and / or orientation of the refractive test elements 11, 12 of the optometric device, in particular the refractive unit 10.

[0326] - It avoids the limitation of a small pupil distance under near conditions, as Figure 4 shown

[0327] - It allows the optometric device to perform a subjective refractive test for any visual distance between distance and near conditions with the same display device.

[0328] The optometric device described herein is a conventional optometric device for determining the refractive characteristics of a subject's eyes in a subjective refractive test. The accessory device is for determining the refractive characteristics of a subject's eyes.

[0329] Alternatively, the accessory device can be used with the same type of optometric device or any other compatible optometric device to test different characteristics of a subject's eyes, such as the visual performance, dominant eye, vergence, phoria, objective or subjective characteristics of the subject's eyes.

Claims

1. An accessory device (2) for testing a subject's eyes (E1, E2) in near or intermediate vision conditions, the accessory device being designed to be used together with an optometric device (1) for measuring the subjective refractive value of the eyes (E1, E2), the optometric device (1) comprising: - a refractive test unit (10) having optical components (11A, 12A) for providing different refractive powers to the subject's eyes (E1, E2) during a subjective refractive test, and - a display unit (20) adapted to generate visual targets (T1, T2) for the subject's eyes (E1, E2), the images of the visual targets (T1, T2) being visible through the refractive test unit (10) along a reference viewing direction (OBS1), The accessory device (2) includes an optical portion (40) configured to be mounted on the refractive test unit (10) of the optometric device (1), the optical portion including an optical system (41, 42) configured to deflect the image of the visual target (T1, T2) from the reference viewing direction (OBS1) towards an inclined viewing direction (OBS2, OBS3), the image of the visual target (T1, T2) being visible along the inclined viewing direction through the refractive test unit (10) and the optical portion (40) of the accessory device (2), when the optical portion (40) is mounted on the refractive test unit (10) of the optometric device (1), the inclined viewing direction (OBS2, OBS3) defines a non-zero angle (A1, A2) with the reference viewing direction (OBS1) and corresponds to the subject's downward gaze direction and / or the subject's convergent gaze direction.

2. The accessory device (2) according to claim 1, wherein, the optical system (41, 42) includes a reflective or semi-reflective surface and / or an optical lens.

3. The accessory device (2) according to any one of claims 1 and 2, wherein, the optical system (41, 42) includes two optical elements (411, 412, 421, 422), a first optical element (411, 421) of the two optical elements being configured to be placed at an effective position in front of the exit hole of the optometric device (1) to deflect the image of the visual target (T1, T2) and transmit it to a second optical element (412; 422) of the two optical elements, the second optical element (412; 422) being configured to deflect the image of the visual target along the inclined viewing direction (OBS2).

4. The accessory device (2) according to claim 3, wherein, The first optical element (411, 421) is movable between the effective position and the second position. At the effective position, the first optical element is placed in front of the optical components (11A, 12A) of the optometric device (1) in the reference viewing direction (OBS1) of the optometric device (1). At the second position, the first optical element is placed outside the reference viewing direction (OBS1).

5. The accessory device (2) according to any one of claims 1 to 4, wherein, the accessory device (2) includes a determination tool (31) configured to determine the visual correction power of the subject's eyes (E1, E2) in consideration of the final value of the parameter representing the relative position of the eyes (E1, E2) and the optical components (11A, 12A) of the optometric device (1) in the presence of the accessory device (2).

6. The accessory device (2) according to claim 5, wherein, the determination tool (31) is configured to determine the visual correction power according to the value of the parameter representing the relative position of the image representing the visual target (T1, T2) and the eyes (E1, E2) of the subject.

7. The accessory device according to any one of claims 1 to 6, wherein, the determination tool (31) includes a software part programmed to calculate the visual correction power.

8. The accessory device according to claim 7, wherein, the optometric device (1) includes a control device (30) programmed to determine the reference visual correction power of the subject's eyes (E1, E2) in consideration of the refractive power provided by the refractive test unit (1) to the eyes (E1, E2) of the subject and the reference value of the parameter representing the relative position of the eyes (E1, E2) and the optical components (11A, 12A) in the absence of the accessory device (2), and the software part is configured to be implemented by the control device (30) of the optometric device (1).

9. The accessory device according to any one of the preceding claims, wherein, the accessory device (2) includes an adjustment tool (32) configured to adjust the position and / or orientation of each visual target displayed by the display unit based on the inclination of the inclined viewing direction, and / or to adjust the refractive power of the optical components (11A, 12A) of the optometric device (1) based on the value of the parameter representing the relative position of the image representing the visual target (T1, T2) and the eyes (E1, E2) of the subject.

10. The accessory device according to any one of claims 1 to 6, wherein, the determination tool includes a database including data related to the visual correction power of the subject's eyes, the data being associated with the value of the quantity representing the relative position of the subject's eyes and the optical components of the optometric device determined in the presence of the accessory device.

11. The accessory device according to any one of claims 1 to 10, Wherein, the optical part (40) includes a housing (43), the optical systems (41, 42) are accommodated in the housing, and the housing (43) is configured to be attached to the refractive test unit (10) of the optometry device (1).

12. The accessory device according to claim 3, Wherein, the refractive test unit (10) of the optometry device (1) has two optical components (11A, 12A) for providing different refractive powers to the two eyes (E1, E2) of the subject. The optical part (40) of the accessory device (2) includes two optical systems (41, 42), each optical system (41, 42) is configured to be placed in front of one of the two optical components (11A, 12A) of the optometry device (1), so as to allow the eyes (E1, E2) of the subject to be tested under binocular vision. Each optical system (41, 42) includes the first optical element and the second optical elements (411, 412, 421, 422). The two first optical elements (411, 421) extend in the same first plane, and the two second optical elements (412, 422) extend in the same second plane. The relative positions and / or orientations of the two first optical elements (411, 421) and the relative positions and / or orientations of the two second optical elements (412, 422) are fixed.

13. The accessory device according to claim 3, Wherein, the refractive test unit (10) of the optometry device (1) has two optical components (11A, 12A) for providing different refractive powers to the two eyes (E1, E2) of the subject. The optical part (40) of the accessory device (2) includes two optical systems (41, 42), each optical system (41, 42) is configured to be placed in front of one of the two optical components (11A, 12A) of the optometry device (1), so as to allow the eyes (E1, E2) of the subject to be tested under binocular vision. Each optical system includes the first optical element and the second optical elements (411, 412, 421, 422). The position and / or orientation of each first optical element (411, 421) of the optical system is independently adjustable from each other, and the position and / or orientation of each second optical element (412, 422) of the optical system is independently adjustable from each other.

14. An optometry system, the optometry system includes an accessory device (2) for testing the eyes of a subject under ergonomic conditions for near vision or intermediate vision according to any one of claims 1 to 13 and an optometry device (1) for measuring the subjective refractive value of the eyes, the optometry device (1) comprises: - a refractive test unit (10) having optical components (11A, 12A) for providing different refractive powers to the eyes (E1, E2) of the subject, and - A display unit (20) adapted to generate visual targets (T1, T2) for the eyes (E1, E2) of the subject, the images of the visual targets (T1, T2) being visible through the refractive test unit (10) of the optometric device (1) along a reference viewing direction (OBS1), wherein the optical portion (40) of the accessory device (2) is mounted on the refractive test unit (10).

15. A method for testing the eyes of a subject in distance vision and near or intermediate vision conditions using the optometric system according to claim 14, the method comprising: - Performing a visual test in distance vision conditions when the subject observes the image of the visual target (T1, T2) displayed by the display unit (20) of the optometric device (1) along the reference viewing direction (OBS1), the image not being deflected by the accessory device (2), - Using the accessory device (2) to deflect the image of the visual target (T1, T2) towards the inclined viewing directions (OBS2, OBS3), - Performing a visual test in near or intermediate vision conditions when the subject observes the image of the visual target (T1, T2) displayed by the display unit (20) of the optometric device (1) and deflected by the accessory device (2) along the inclined viewing directions (OBS2, OBS3), without moving the refractive test unit (10) between performing the visual test in distance vision conditions and performing the visual test in near or intermediate vision conditions.

Images