Accessory device for testing a subject's eyes in near or intermediate vision conditions - Patent Application 20070122997

Abstract

The present invention relates to an accessory device (2) for testing eyes (E1, E2) in near or intermediate vision conditions, designed to be used with an optometric device (1) for measuring the subjective refraction of the eyes (E1, E2), the accessory device (2) comprising a refraction testing unit (10) having optical components (11A, 12A) for providing different refractive powers to the subject's eyes (E1, E2) during a subjective refraction test, and a display unit (20) adapted to generate visual targets (T1, T2) for the subject's eyes (E1, E2), the images of which are visible through the refraction testing unit (10) along a reference observation direction (OBS1), and the accessory device (2) an optical portion (40) configured to be attached to a refraction testing unit (10) of an optometric device (1), the optical portion (40) comprising optical systems (41, 42) configured to shift an image of a visual target (T1, T2) from a reference observation direction (OBS1) toward oblique observation directions (OBS2, OBS3) along which the image of the visual target (T1, T2) is visible through the refraction testing unit (10) and the optical portion (40) of the accessory device (2), the oblique observation directions (OBS2, OBS3) defining non-zero angles (A1, A2) with the reference observation direction (OBS1) when the optical portion (40) is attached to the refraction testing unit (10) of the optometric device (1), and corresponding to a downward gaze direction of a subject and / or a convergence gaze direction of a subject.

Description

[Technical Field]

[0001] The present invention relates to an accessory device for examining the eyes of a subject, and also to an optometric system and related methods including such an accessory device for use in conjunction with a conventional optometric device. [Background technology]

[0002] Known devices and methods for testing a subject's eyes are typically specialized for testing the eyes in distance viewing conditions, where the target presented to the subject to test their binocular distance vision is typically positioned more than 5 meters, preferably 3-5 meters, from the subject's eyes.

[0003] However, the refractive properties of the eye in near and / or intermediate viewing conditions may differ from those in far viewing. This may be due, among other things, to the fact that the eye's accommodation and convergence are different in near and / or intermediate viewing conditions. It is known that near viewing in horizontal gaze does not require the same vision correction as near viewing in downward gaze.

[0004] It is also known that accommodation is not the same in binocular and monocular vision, but varies depending on the direction of gaze and the vision used (monocular or binocular).

[0005] Furthermore, the exact value of the refractive characteristics of the eye or the required vision-correcting refractive power is usually obtained through subjective measurement methods using an optometric device adapted to perform such subjective determination of the refractive characteristics of the eye.

[0006] Known methods for testing a subject's eyes in near and / or intermediate vision are performed while the subject is wearing a trial frame with trial lenses. These methods do not allow for precise control of the refractive conditions (gaze tilt, posture, object, and eye-lens distance...) and do not allow for the trial lens to be kept centered in front of the subject's eye. Unwanted aberrations (oblique astigmatism due to a non-perpendicular angle of gaze on the lens) can be introduced, resulting in deviations that are detrimental to determining the vision correction required by the subject.

[0007] An alternative known method for testing a subject's eyes in near and / or intermediate vision uses an ophthalmic device, also called a phoropter, which helps to ensure centering of the optical system on the visual axis, eye-lens distance, posture control, and object (target) distance to avoid undesirable aberrations.

[0008] Such a phoropter comprises a refraction testing unit and a support element designed to receive the individual's head and hold it in position relative to the refraction testing unit.

[0009] The refraction testing unit contains one or more trial lenses providing different vision corrections, which can be successively placed in front of the subject's eyes until the appropriate vision correction value is found.

[0010] In practice, multiple trial lenses can be placed on two freely rotatably mounted discs, so that the trial lenses on the discs can be placed in succession in front of the corresponding subject's eyes. Alternatively, a single lens with variable refractive power can be placed in front of the subject's eyes, optionally in relation to the other lenses.

[0011] Phoropters typically only allow measurements in the subject's straight-on gaze direction, resulting in unnatural posture for near and / or intermediate vision.

[0012] Some phoropters can be used in the subject's downward or convergence gaze direction. However, none of the existing phoropters can determine the subjective refraction of the eye in downward gaze without complex and cumbersome positioning steps. In fact, such a determination requires rotating the refractive unit of the phoropter and positioning it in front of the subject's eye as they look downward. The refractive unit of known phoropters rotates around an axis located far above the eye, and tilting significantly changes the height of the phoropter, necessitating a complete readjustment of the subject's position. Furthermore, the ergonomics of phoropters do not allow for downward gaze while maintaining proper alignment between the eye and the phoropter's optics in comfortable conditions; that is, the shape of the phoropter often pinches the subject's nose or rests against the cheekbone. In addition, the conditions for near and / or intermediate vision testing are uncomfortable for the patient and difficult for eye care professionals to control. Summary of the Invention [Problem to be solved by the invention]

[0013] It is therefore an object of the present invention to provide an accessory device that can be used with an optometric device for examining a subject's eyes in near or intermediate vision conditions, without cumbersome adjustments, in comfortable and near-natural near or intermediate vision conditions. [Means for solving the problem]

[0014] The above object is achieved according to the present invention by providing an accessory device for testing the eye of a subject in near or intermediate vision conditions, designed to be used with an optometric device for measuring the subjective refraction of the eye, the accessory device comprising: - a refraction testing unit having optical components for providing different refractive powers to the subject's eyes during subjective refraction testing; a display unit adapted to generate a visual target for the subject's eye, the image of the visual target being visible through the refraction testing unit along a reference observation direction; and Equipped with The accessory device comprises an optical part configured to be attached to a refraction testing unit of an optometric device, the optical part comprising an optical system configured to shift an image of the visual target from the reference observation direction towards an oblique observation direction along which the image of the visual target is visible through the refraction testing unit and the optical part of the accessory device, the oblique observation direction defining a non-zero angle with the reference observation direction when the optical part is attached to the refraction testing unit of the optometric device and corresponding to a downward gaze direction of the subject and / or a convergence gaze direction of the subject.

[0015] The accessory device is designed to be used in conjunction with a conventional ophthalmic device.

[0016] Thanks to the accessory of the present invention, it is possible to easily perform subjective testing of a subject's eyes in near and / or intermediate vision conditions using a conventional optometric device, even if the conventional optometric device itself is only capable of measuring distance vision.

[0017] By attaching the accessory device of the present invention to an optometric device, it is possible to actually change the optical path along which light is directed from a visual target to a subject's eye. Within the optometric device, in the absence of the accessory device, light is directed along a reference optical path that corresponds to the subject's horizontal forward viewing direction in distance viewing conditions. The accessory device changes the optical path along which light is directed to a final optical path, where the light is deflected from the reference optical path by a non-zero angle and toward a direction that corresponds to the subject's downward and / or vergence viewing direction in near or intermediate viewing conditions.

[0018] The downward gaze direction forms a non-zero angle with the reference horizontal forward gaze direction in a vertical plane passing through the reference gaze direction, and the convergence gaze direction forms a non-zero angle with the reference horizontal forward gaze direction in a horizontal plane passing through the reference gaze direction.

[0019] In other words, incident light rays that enter the accessory device along a horizontal straight-line incident direction are deflected by the optical system and exit the accessory device along oblique exit directions that form a non-zero angle with the horizontal straight-line incident direction in at least one of a horizontal plane and a vertical plane, each of which passes through the reference gaze direction.

[0020] The present invention makes it possible to test a subject's eyes for subjective refraction due to downgaze and / or convergence using an optometric device originally configured to determine the vision-correcting refractive power in the subject's forward looking direction.

[0021] According to a further non-limiting feature of the device of the present invention, - the optical system comprises a reflective or semi-reflective surface and / or an optical lens, - the optical system comprises two optical elements, a first of the two optical elements being arranged in an operative position in front of an exit opening of the optometric device and configured to transmit the image of the visual target in a displaced manner to a second of the two optical elements, the second optical element being configured to displace the image of the visual target along the oblique observation direction; the first optical element is movable between an operating position disposed in front of optical components of the optometric device in the reference viewing direction and a second position disposed outside the reference viewing direction; - the accessory device comprises a determination tool configured to determine a vision-correcting refractive power of the eye of the subject taking into account final values ​​of parameters representative of a relative position of the eye and an optical component of the optometric device in the presence of the accessory device; - the determination tool is configured to determine the vision-correcting refractive power taking into account a refractive power provided by a refraction testing unit of an optometric device during the subjective refraction test; - the determination tool is configured to determine the vision-correcting refractive power in response to a value of a parameter representing a relative position between an image of a visual target viewed through an accessory device and the subject's eye; - the determination tool is configured to determine the vision-correcting refractive power in response to a reference value of a parameter representing a relative position of the eye and an optical component of the optometric device in the absence of the accessory device, such as a reference value of an optical vertex distance between the eye and the optical component of the optometric device; - the determination tool includes a software portion programmed to calculate the vision-correcting refractive power; - the optometric device comprises a control device programmed to determine a reference vision-correcting refractive power for the subject's eye, taking into account the refractive power provided to the subject's eye by a refraction testing unit and reference values ​​of parameters representing the relative position of the eye and an optical component in the absence of the accessory device, and the software portion is configured to be implemented by the control device of the optometric device; - the accessory device comprises an adjustment tool configured to adjust a position and / or an orientation of each visual target displayed by the display unit based on a tilt of the tilt observation direction, and / or to adjust a refractive power of an optical component of the optometric device based on a value of a parameter representing a relative position between an image of the visual target and an eye of the subject; - the determination tool comprises a database containing data related to the vision-correcting refractive power for the subject's eye linked to values ​​of the parameters representing the relative positions of the subject's eye and optical components of the optometric device in the presence of the accessory device; the optical part comprises a housing in which the optical system is accommodated, the housing being configured to be attached to a refraction testing unit of an optometric device; - the refraction examination unit of the optometric device has two optical components for providing different refractive powers to both eyes of the subject, and the optical part of the accessory device comprises two optical systems, each configured to be placed in front of one of the two optical components of the optometric device, allowing the subject's eyes to be examined with binocular vision, each optical system comprising the first and second optical elements, the two first optical elements extending in the same first plane and the two second optical elements extending in the same second plane, and the relative positions and / or orientations of the two first optical elements and the two second optical elements being fixed; - the refraction examination unit of the optometric device has two optical components for providing different refractive powers to both eyes of the subject, and the optical part of the accessory device comprises two optical systems, each configured to be placed in front of one of the two optical components of the optometric device, allowing the subject's eyes to be examined with binocular vision, each optical system comprising the first and second optical elements, the positions and / or orientations of each first optical element of the optical systems being adjustable independently of each other, and the positions and / or orientations of each second optical element of the optical systems being adjustable independently of each other; - the refraction examination unit of the optometric device has two optical components for providing different refractive powers to the two eyes of the subject, and the optical part of the accessory device comprises two optical systems configured to be placed in front of the two optical components of the optometric device and allowing the subject's eyes to be examined with binocular vision, each optical system comprising the first and second optical elements, the position and / or orientation of each first optical element of the set being adjustable independently of each other, and the relative position and / or orientation of the second optical element of the set being fixed, - the software portion is configured to determine the vision-correcting refractive power based on a reference vision-correcting refractive power, a reference value of the distance between the subject's eye and an optical component of the optometry device, and a final value of the distance between the subject's eye and the optical component; - the software portion is configured to determine the vision-correcting refractive power taking into account a distance between an image of an optotype viewed through the optometric device and the accessory device and the subject's eye; - the vision-correcting refractive power corresponds to an equivalent refractive power at a predetermined standard distance between the eye and an optical component of the optometric device; - the vision-correcting refractive power is calculated using a predetermined formula or a ray tracing algorithm; the software portion is configured to adjust the position and / or orientation of each target displayed by the display unit based on the inclination of the oblique observation direction.

[0022] The present invention also relates to an optometry system including the above-mentioned accessory device and an optometry device for measuring the subjective refractive value of an eye, the optometry device comprising: - a refraction testing unit having optical components for providing different refractive powers to the subject's eyes; - a display unit adapted to generate a visual target for the eye of the subject, an image of the visual target being visible through the refraction testing unit of the optometric device along a reference observation direction; and Equipped with The optical portion of an accessory device is attached to the refraction testing unit.

[0023] The optical system is configured to shift an image of a visual target from the reference viewing direction toward an oblique viewing direction that defines a non-zero angle with the reference viewing direction.

[0024] Advantageously, the optical system is arranged to be placed in a predetermined fixed position relative to the subject's eye, with the centre of rotation of the eye lying in the reference observation direction and in the oblique observation direction.

[0025] The present invention also proposes a method for testing the eyes of a subject in distance and near or intermediate vision conditions using the above-mentioned optometry system, said method comprising: - performing a visual acuity test under a distance viewing condition, with the subject observing an image of one or more optotypes displayed by a display unit of the optometric device along the reference observation direction, which is not displaced by the accessory device; and - using the accessory device to displace the image of the visual target toward the oblique observation direction; - performing a visual acuity test in a near or intermediate vision condition, while the subject observes an image of a target displayed by a display unit of the optometric device and displaced by an accessory device along the oblique observation direction, without moving a refraction test unit between performing the visual acuity test in far vision and performing the visual acuity test in near or intermediate vision. Includes:

[0026] Advantageously, the method of the present invention also allows for performing visual acuity tests in near or intermediate viewing conditions without moving the subject's head.

[0027] The following description, which refers to the accompanying drawings, should make clear what constitutes the present invention and how it can be put into practice. The present invention is not limited to the embodiments shown in the drawings. Thus, if features recited in a claim are followed by reference signs, such signs are included solely for the purpose of enhancing the comprehension of the claim and in no way limit the scope of the claim. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram of the optical arrangement of a prior art optometric device used to measure the refraction of a subject's eye in distance viewing conditions; FIG. [Figure 2] 2 is a schematic diagram of an optical arrangement of an optometric system according to the present invention, including an accessory device coupled to the optometric device of FIG. 1 , configured to measure the refraction of a subject's eye in downward gaze, near vision, or intermediate vision conditions. [Figure 3]3 is a schematic diagram of the optometric system of FIG. 2 configured to measure the refraction of a subject's eye in a horizontal forward viewing direction and in a distance viewing condition. [Figure 4] 3 is a schematic diagram of an overhead view of the optometric system of FIG. 2 configured to measure the refraction of a subject's eye in convergence, near, or intermediate viewing conditions. [Figure 5] 3 is a schematic diagram of the optometric system of FIG. 2 showing a first embodiment of an accessory device of the present invention attached to the optometric device. [Figure 6] FIG. 6 is an enlarged front view of the accessory device of FIG. 5 attached to an optometric device. [Figure 7] 6 is a schematic profile diagram of a subject looking through the accessory device of FIG. 5, with the accessory device configured to measure the refraction of the subject's eye in a distance viewing condition. [Figure 8] 6 is a schematic profile diagram of a subject looking through the accessory device of FIG. 5, with the accessory device configured to measure the refraction of the subject's eye in downward gaze, near or intermediate viewing conditions. [Figure 9] 1 is a schematic front view of a second embodiment of an accessory device of the present invention. [Figure 10] 1 is a schematic diagram of an optometric system of the present invention having a first variant of an accessory device, the accessory device comprising two optical systems adapted to be placed in front of one of the subject's eyes, each having a fixed overall position and orientation relative to the optometric device, each comprising a first and a second optical element, the first optical element of both optical systems being made from a single piece, and the second optical element of both optical systems being made from a single piece. [Figure 11] 1 is a schematic diagram of an optometric system of the present invention having a second variant of the accessory device, the accessory device comprising two optical systems, each of which is positioned in front of one of the subject's eyes, the optical elements of the two optical systems being separated from each other but remaining in a fixed position and orientation relative to the optometric device and not necessarily aligned with the optical axes of the optical components of the optometric device. [Figure 12] 1 is a schematic diagram of an optometric system of the present invention having a third variant of an accessory device, the accessory device comprising two optical systems, each of which is positioned in front of one of the subject's eyes, the two optical systems being separated from each other and independently coupled to a portion of the optometric device, and the optical elements of each optical system being aligned with the optical axis of the optical components of the optometric device. [Figure 13] 1 is an example of an optotype displayed by an optometry device. [Figure 14] 14 shows the image of the target of FIG. 13 as seen by each subject's eye when the accessory device is combined with the optometric device in the configuration shown in FIG. 12. [Figure 15] This is a superposition of both images of the target in Figure 14. [Figure 16] 13 is an example of an optotype that is corrected by the software portion of the accessory device when the accessory device is coupled to the optometric device in the configuration depicted in FIG. 12. [Figure 17] A superposition of both images of the target in Figure 16 as seen by the subject's eye through the accessory device. [Figure 18] 1 is an optical scheme of the optical configuration of the optometry system and the subject's eye used to calculate the vision-correcting refractive power. DETAILED DESCRIPTION OF THE INVENTION

[0029] In the following description, identical or corresponding elements of the embodiments and variants of the invention are designated by the same reference numerals.

[0030] The direction of light propagation is indicated by arrows.

[0031] The present invention relates to an accessory device 2 for testing a subject's eyes in near or intermediate viewing conditions when used with an optometric device 1 .

[0032] The present invention also relates to an optometric system 3 comprising an optometric device 1 and an accessory device 2 attached thereto.

[0033] The optometric device 1 is configured to measure the subjective refraction of an eye by determining the reference vision-correcting refractive power required by the subject's eye to achieve a target visual performance, as will be described in more detail below. Fig. 1 shows a schematic diagram of a prior art optometric device without an accessory device 2. Figs. 2-4 and 6-12 show schematic diagrams of an optometric system 3 of the present invention, which includes an optometric device 1 similar to that of Fig. 1 and an accessory device 2 of the present invention.

[0034] Typically, the subjective test involves several steps, during each of which the subject is required to compare two different optical situations, taking into account test values ​​of optical properties such as spherical power and / or cylindrical power and / or axiality of the optical components of the optometric device. Thus, the subjective test corresponds to a series of steps. Depending on the subject's feedback regarding this comparison (the subject's answers), the eye care professional increases the test values ​​and, in the next step of the subjective test, presents the subject with two new different optical situations based on the increased test values. This process is repeated until a specific answer or combination of answers is provided by the subject. An example of such an optometric device 1 is shown in Figures 1-12.

[0035] The optometric device 1 is commonly referred to as a "phoropter." A phoropter is a conventional optometric device and can be of any type known to those skilled in the art. A phoropter can be manual or automatic. A phoropter can also include a virtual reality headset with a light field display.

[0036] Such optometric devices 1 and their use in subjective refraction testing are known and only their main features will be described below.

[0037] 1 to 3, the optometry device 1 includes a refraction examination unit 10 and a display unit 20. The optometry device 1 is generally used to examine the eyes of a subject, preferably in a far-vision condition.

[0038] The known subjective refraction test can be performed in binocular or monocular viewing conditions. The subjective test for determining the vision correction refractive power can be preferably performed in binocular viewing conditions. The complete subjective refraction test or the subjective test for determining the add power can be performed in near viewing conditions in the above-mentioned reference observation direction OBS1.

[0039] The refraction testing unit 10 of the optometric device 1 comprises at least optical refractive elements 11, 12 for providing different refractive powers to the subject's eye.

[0040] The optometric device 1 is preferentially used to perform binocular measurements to determine at least one refractive property of a first eye E1 and / or a second eye E2 of a subject in a binocular manner.

[0041] However, the optometric device 1 can also be used for monocular measurements, for which a phoropter with one optical refractive element and one image displayed is conceivable.

[0042] The determination of the refractive properties of the eyes in both eyes is based on binocular measurements performed when the subject has both eyes E1, E2 open and unobstructed.

[0043] Thus, the refraction testing unit 10 of the optometric device 1 comprises two optical refractive elements 11, 12 for providing different refractive powers to both eyes E1, E2 of the subject, as shown in FIG.

[0044] The refraction testing unit 10 comprises a first optical refractive element 11 adapted to provide different vision-correcting refractive powers along a first optical axis OA1 and a second optical refractive element 12 adapted to provide different vision-correcting refractive powers along a second optical axis OA2 (Figures 4 and 10 to 12).

[0045] The first optical refractive element 11 is configured to provide a first corrective refractive power to a first eye E1 of the subject, and the second optical refractive element 12 is configured to provide a second corrective refractive power to a second eye E2 of the subject.

[0046] In the optometric device 1 shown in the accompanying figures and described below, each of the first and second optical refractive elements 11, 12 comprises at least an optical component 11A, 12A, such as a lens or a mirror or a prism, which has adjustable refractive power characteristics or allows the refractive power to be adjusted by rotation or translation of the optical component or by electrical command, or a set of such optical components.

[0047] In practice, the optical components 11A and 12A include, for example, lenses with variable refractive power, where the lenses with variable refractive power include deformable liquid lenses with adjustable shapes, and thus the above-mentioned optical axes OA1 and OA2 coincide with the optical axes of the corresponding lenses.

[0048] Each optical component 11A, 12A may include a lens with variable spherical power and a lens with variable cylindrical power and variable cylindrical axis. Each optical component 11A, 12A may also include a prism or any other component adapted to provide prismatic power to the subject's eye. The resulting optical components are shown schematically in the drawings by lenses 11A, 12A (FIGS. 1-4, 10-12).

[0049] Alternatively or additionally, the optical component may comprise a collection of non-deforming lenses with different optical powers and a mechanical system that allows selecting some of these lenses and grouping them to form a set of lenses through which the subject can see. In this last case, to adjust the refractive power of the set of lenses, one or more lenses of the set of lenses are replaced by other lenses stored in the refraction testing unit. The aforementioned optical axis thus coincides with the optical axis of a lens placed in front of the subject's eye.

[0050] Each of the refractive optical elements 11, 12 is intended to be placed in front of and close to one of the subject's eyes E1, E2.

[0051] The relative position between the subject's eyes and the corresponding optical components 11A, 12A of the optical refractive elements 11, 12 is quantified by the value of a parameter that represents this relative position between the subject's eyes E1, E2 and the optical components 11A, 12A of the refraction testing unit 10.

[0052] The values ​​of the parameters representing this relative position between the subject's eyes E1, E2 and the optical components 11A, 12A of the refraction testing unit 10 may be measured, calculated, estimated or predetermined.

[0053] This parameter may be the distance measured between the optical component 11A, 12A of the optical refractive element 11, 12 directed towards the eye and the eye E1, E2 positioned in front of it, for example between the apex of curvature of the outer surface of the optical component 11A, 12A and the apex of curvature of the cornea of ​​the eye.

[0054] More precisely, said parameter may be the optical vertex distance, defined as the optical distance between the rear surface of the lens of the optical component 11A, 12A and the apex of the cornea of ​​the eye.

[0055] The distance measured may be a physical distance or an optical distance. The physical distance between two points corresponds to the distance measured along a straight line between the two points. The optical distance is measured along the optical path of light between the two points. The optical distance may or may not take into account the refractive index of the material through which the light path is placed. Thus, the optical distance between two points may correspond to the physical distance measured between the two points while following the optical path of light from one point to the other.

[0056] For example, the optical distance between two points is equal to the sum of the physical distances measured between successive intersections between the path of light and the surface of an optical component. If the refractive index of a material is taken into account, 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 distance traveled in air multiplied by the refractive index of air, and / or the sum of the physical distances traveled in said different materials multiplied by the refractive index of the material corresponding to each physical distance.

[0057] The parameter may also be defined, for example, as the optical distance between the center of rotation of the eye and the optical component, without taking into account the refractive index of the material through which the light travels.

[0058] This parameter may also be an angle.

[0059] The values ​​of the above parameters may be, for example, measured manually, determined based on images of the subject's head and the optometric device, or predetermined as being equal to an average value. The accessory device 2 may comprise a measuring device, as will be explained in more detail below.

[0060] As will be described in detail later, the optometric device 1 makes it possible to determine the reference vision-correcting refractive power of the subject's eyes E1, E2, taking into account the refractive power provided to the subject's eyes by the refraction examination unit 10 and reference values ​​of the parameters representing the relative positions of the eyes and the optical components in the absence of the accessory device 2. The reference vision-correcting refractive power corresponds to the reference value of the vision-correcting refractive power required by the subject's eyes to achieve target vision performance, determined with the reference values ​​of the parameters representing the relative positions of the subject's eyes E1, E2 and the optical components 11A, 12A of the refraction examination unit 10.

[0061] The relative positions of the subject's eye and the optical components 11A, 12A of the optometric device 1 are controlled, for example, by using one or more positioning elements adapted to receive the subject's head.

[0062] The one or more positioning elements may belong to the refraction testing unit 10. The one or more positioning elements may be designed to hold the subject's head in a predetermined position relative to the refraction testing unit 10.

[0063] The refraction testing unit 10 comprises a positioning element 15 adapted to receive, for example, the forehead of the subject (see FIG. 5). Alternatively or additionally, the refraction testing unit may comprise an element adapted to receive the chin of the subject.

[0064] The position adjustment element may then be used to obtain predetermined values ​​of parameters that describe the relative positions of the eye and the optical components 11A, 12A.

[0065] The position adjustment element is configured to ensure that the optical vertex distance between the subject's eye and the optical components 11A, 12A of the optometric device 1 in the absence of the accessory device 2 is predetermined and equal to a target value of the optical vertex distance equal to 12 mm.

[0066] The following describes an ophthalmic device 2 in which each optical component 11A, 12A includes a lens with variable spherical refractive power, a lens with variable cylindrical refractive power and variable cylindrical axis, and optionally a prism, which are indicated in the drawings by lenses having reference numerals 11A, 12A.

[0067] The optical components 11A, 12A have an overall spherical power S expressed in diopters and corresponding to the spherical power. The optical components 11A, 12A have a cylindrical power C also expressed in diopters and an orientation represented by an angle A. Each of the first and second optical powers provided by the corresponding optical refractive elements 11, 12 can be characterized by the values ​​of these three power parameters S, C, and A.

[0068] The refractive optical elements 11, 12 are mounted on a common support 13 (Fig. 5) which extends above and between the refractive optical elements 11, 12 along a horizontal longitudinal axis H (Fig. 5).

[0069] This support 13 is connected to an overall support structure 14 (partially shown in Figure 5) that rests on a table or on the ground.

[0070] Each of the refractive optical elements 11, 12 is mounted on a support 13 so as to be rotatable about a rotation axis V1, V2 perpendicular to the longitudinal axis H (FIG. 5). The mean planes MP of the first refractive optical element 11 and the second refractive optical element 12 pass through these axes V1, V2 (FIG. 5). This mobility of the refractive optical elements makes it possible to adjust the orientation of the optical axes OA1, OA2 of the optical components 11A, 12A. In particular, the optical components 11A, 12A may then be oriented to take into account the convergence of the subject's eyes.

[0071] The optometric device 1 also includes a display unit 20 for presenting one or more visual targets T1, T2. The display unit 20 is adapted to generate visual targets for the subject's eyes, and images I1, I2, I1', I2' of the displayed visual targets T1, T2 are visible through the refraction testing unit 10 along a reference observation direction OBS1. This reference observation direction OBS1 extends along the optical axes OA1, OA2 of the optical components 11A, 12A of the refraction testing elements 11, 12 (FIG. 1). The reference observation direction OBS1 corresponds to the horizontal forward viewing direction. Images of the visual targets are visible through the exit openings of the optical refractive elements 11, 12 of the optometric device 1.

[0072] The image of the visual target may be the visual target itself when viewed directly by the subject, or it may be a real or virtual image of the visual target through the optical setup of the optometric device 1, and optionally of the accessory device 2 when attached to said optometric device 1.

[0073] Preferentially, a first target T1 and a second target T2 are provided for binocular testing, with images I1, I1' of the first target being transmitted along a first optical path to a first refractive element 11 and images I2, I2' of the second target being transmitted along a second optical path to a second refractive element 12.

[0074] Thus, the image display unit 20 is configured to provide an image of a first visual target to the subject's first eye E1 and simultaneously provide an image of a second visual target to the subject's second eye E2. The first and second visual targets may be the same or different from each other.

[0075] The image of the first visual target is seen by the subject's first eye E1 through the first optical refractive element 11, while the image of the second visual target is seen by the subject's second eye E2 through the second optical refractive element 12.

[0076] The images I1', I2' of the visual targets T1, T2 provided to both eyes E1, E2 are preferably configured so that fusion of the two visual targets by the subject's brain can occur (FIG. 17). Preferably, the two visual targets are stereoscopic images that provide the subject with an at least partially three-dimensional representation.

[0077] To this end, each target is configured to be precisely optically aligned with the subject's corresponding eye.

[0078] Preferably, the first and second optical paths allow for testing the subject's eye in far vision, and the optical distance corresponding to the optical paths is preferably greater than 1.5 meters, even more preferably between 3 and 5 meters.

[0079] The display unit 20 may comprise a printed visual indicator. In another embodiment, the display unit 20 may comprise one or more electronic devices each comprising a screen and / or an element adapted to display the visual indicator. The screen may be, for example, one of an LED or OLED 20 screen, a silk screen with a backlight screen, a display light projection screen with a miniature video projector, an LCD screen, or a TFT screen. In that case, the display unit 20 comprises an active screen that generates a light beam.

[0080] In another embodiment, the display unit comprises a projector and a projection element adapted to project one or more visual indicia, where "projected" means that each visual indicia is formed by a projection element, such as a lens.

[0081] Each target may be projected onto a passive screen or directly onto the retina of the subject's eye.

[0082] Each of the visual targets T1, T2 may include, for example, one or more visual acuity charts (FIG. 13). Each of the visual targets may include any type of visual target adapted to test the visual acuity of a subject known to those skilled in the art.

[0083] Preferably, the optometric device 1 also includes a control device 30. The control device 30 may include a processor and an interface such as a screen. The control device 30 is programmed to determine a reference vision-correcting refractive power for the subject's eye based on a subjective test performed using the optometric device 1.

[0084] The control device 30 is programmed to determine a reference vision-correcting refractive power for the subject's eyes E1, E2 taking into account the refractive powers provided to the subject's eyes E1, E2 by the refraction testing unit 1. The control device 30 may also take into account reference values ​​of parameters representative of the relative positions of the eyes E1, E2 and the optical components 11A, 12A in the absence of the accessory device 2.

[0085] Such control devices 30 are well known and will not be described in further detail here.

[0086] As described above, the optometric device 1 is configured to position the optical components 11A, 12A in a reference position relative to the subject's eye, which corresponds to the reference values ​​of the parameters that describe the relative positions of the eye and the optical components of the optometric device in the absence of the accessory device.

[0087] A subjective test is performed at the reference values ​​of parameters representing the relative positions of the eye and the optical components of the optometric device to determine the reference vision-correcting refractive power.

[0088] The reference value d0 of the optical vertex distance in the absence of an accessory device corresponds to the optical distance between the corneal apex of the subject's eye and the apex of the rear surface of the optical element 11A, 12A measured along the reference observation direction OBS1 (FIG. 1). The reference value d0 here is equal to the physical horizontal distance measured with the eye in the primary position, i.e., in the horizontal frontal gaze direction.

[0089] The nominal value d0 of the optical vertex distance used in an optometric device 1 without an accessory device 1 is typically equal to 12 mm.

[0090] Alternatively, the reference value d0 of the optical vertex distance may be included in the range of, for example, 11 to 15 mm.

[0091] In practice, the reference vision correction refractive power is usually determined according to test values ​​of the refractive properties of the optical components used during the subjective test, which correspond to the optimum vision correction of the visual defect of the subject's eye.

[0092] "Vision-correcting power" means a diopter power that allows for correcting the refractive error of the subject's eye, such as spherical power, cylindrical power and axis, prismatic power and axis, etc. Multiple vision-correcting power values, including multiple different diopter power values, may also be determined.

[0093] The optometric device 1 without the accessory device 2 is primarily used for measurements performed in the horizontal, frontal gaze direction of the subject. Using this conventional optometric device for measurements in downgaze and / or convergence requires a lengthy positioning process to ensure accurate alignment of the subject's eyes with the optical components of the optical refractive element. Furthermore, the position of the refraction testing unit 10 and / or the subject's head is necessarily changed.

[0094] To easily test the subject's visual acuity in the downgaze and / or convergence direction, an accessory device 2 can be attached to the optometric device 1 to obtain an optometric system 3.

[0095] The gaze direction of one of the subject's eyes corresponds to a line passing through at least two of the following points: the center of rotation of the eye, the center of the eye's pupil, and the center of the visual target.

[0096] 2, the accessory device 2 is shown coupled to the optometric device 1 as described above. The subject's eye is positioned in front of the accessory device 2.

[0097] The accessory device 2 is used to shift the images I1 and I2 of the targets T1 and T2 displayed by the display unit 20 of the optometric device 1 from the reference observation direction OBS1 toward oblique observation directions OBS2 and OBS3 (FIGS. 2 and 4). The oblique observation directions are directed downward (FIG. 2) and / or toward the other eye (convergence) (FIG. 4).

[0098] Distances for far vision are typically comprised between infinity and 1.5 meters in a horizontal forward viewing direction corresponding to a reference angle of 0°. Typical distances for far vision may be comprised between 3 and 5 meters. Distances for intermediate vision are typically comprised between 150 and 50 centimeters in a downward viewing direction of about 15°. Distances for near vision are typically comprised between 50 and 25 centimeters in a downward viewing direction of about 30°.

[0099] The oblique observation direction OBS2 is measured, for example, in a vertical plane containing the reference observation direction OBS1 and is oriented at a downward angle A1 between 15° and 45° from the reference observation direction OBS1, preferably equal to 30° (FIG. 2). The reference observation direction OBS1 typically corresponds to the horizontal forward viewing direction, and the oblique observation direction OBS2 corresponds to downward near viewing.

[0100] The inclined observation direction OBS3 may also be measured in a horizontal plane containing the reference observation direction OBS1 and may be oriented at a convergence angle A2 comprised between 2° and 15° from the reference observation direction OBS1 (FIG. 4). The inclined observation direction OBS2 corresponds to convergence vision.

[0101] According to the present invention, the optometric device 1 comprises: - performing a visual acuity test under a distance viewing condition, while the subject observes images I1, I2 of one or more visual targets T1, T2 displayed by the display unit 20 of the optometric device 1 along the reference observation direction OBS1 that is not deflected by the accessory device 2; - displacing the images I1, I2 of the visual targets T1, T2 towards the oblique observation directions OBS2, OBS3 using the accessory device 2; - performing a visual acuity test in a near or intermediate vision condition, while the subject observes images I1, I2 of the visual targets displayed by the display unit of the optometric device and displaced by the accessory device along the inclined observation directions OBS2, OBS3, without moving the refraction test unit 10 between performing the visual acuity test in far vision and performing the visual acuity test in near or intermediate vision; The eye examination device 2 may be used in conjunction with an accessory device 2 for examining the subject's eyes.

[0102] The visual acuity test is a subjective refraction test as described above. Visual perception of the target is assessed by asking the subject to characterize their perception of the target, by stating whether they see it or not, or by recognizing or not recognizing an eye chart, such as letters. Visual perception can also be assessed, for example, by determining the delay time required for the subject to recognize the eye chart. Assessment of visual perception can be performed by any method known to those skilled in the art.

[0103] Additionally, the optical power and / or visual targets of the lenses in the optometric device are altered in response to the subject's responses during the evaluation step.

[0104] In the above method, the visual acuity test in distance vision may be performed before or after the visual acuity test in near or intermediate vision conditions. Preferably, the visual acuity test in distance vision is performed first.

[0105] For this purpose, the accessory device 2 comprises an optical part 40. The optical part 40 is configured to be attached to the refraction testing unit 10 of the optometric device.

[0106] The optical part 40 comprises one or more optical systems 41, 42 configured to shift the image of the target generated by the optometric device 1 from the reference observation direction OBS1 towards oblique observation directions OBS2, OBS3.

[0107] The oblique observation directions OBS2, OBS3 define non-zero angles with the reference observation direction OBS1 when the optical part 40 is attached to the refraction examination unit 10 of the optometric device 1. In other words, the one or more optical systems 41, 42 are configured to deflect a light beam exiting the optometric device 1 from the reference observation direction OBS1 towards the oblique observation directions OBS2, OBS3.

[0108] The optometric device 1 in this example is configured for binocular measurement, and therefore the refraction examination unit 10 of the optometric device 1 has two optical refractive elements 11, 12 for providing different refractive powers to both eyes of the subject. To this end, the optical part 40 of the accessory device 2 here comprises two optical systems 41, 42, each of which is configured to be positioned in front of one of the two optical refractive elements 11, 12 of the optometric device 1, allowing the subject's eyes to be examined binocularly.

[0109] Each optical system 41, 42 comprises one or more optical elements 411, 412, 421, 422.

[0110] In the examples shown in FIGS. 2 to 12, each of the optical systems 41 and 42 includes two optical elements 411, 412, 421, and 422.

[0111] Each of the optical elements 411, 412, 421, 422 comprises, for example, a reflective or semi-reflective surface.

[0112] In the examples shown in the accompanying Figures 2 to 12, the two reflective surfaces belong to two mirrors. In other embodiments of the invention, the reflective surfaces may belong to a prism, a semi-reflective blade, a spherical mirror, an aspherical mirror, or any kind of suitable optical element known to a person skilled in the art.

[0113] The first optical element 411, 412 of the optical elements 411, 412, 421, 422 is arranged in an operating position in front of one of the exit openings of the optometric device 1 and is configured to displace the visual target and transmit it to the second optical element 421, 422 of the two optical elements 411, 412, 421, 422, which is configured to displace the image of the visual target along the inclined observation directions OBS2, OBS3.

[0114] In the example described below, each optical system 41, 42 comprises a first and a second optical element 411, 412, 421, 422. In a variant, the optical elements may include further optical elements arranged between the first and second optical elements.

[0115] FIG. 2 on the one hand and FIG. 4 on the other hand show two different internal arrangements of the optical portion 40 of the accessory device 2. FIG.

[0116] 2 shows a first relative position of the first and second optical elements 411, 412, 421, 422. In this first relative position, the two plane mirrors corresponding to the two optical elements 411, 412, 421, 422 are arranged at least partially facing each other and partially overlapping along the vertical direction.

[0117] 2, the first mirrors 411, 421 of the accessory device 2 are adapted to be tilted with respect to the reference observation direction OBS1. The first mirrors 411, 421 can be tilted toward the second mirrors 412, 422 at a tilt angle about a horizontal axis perpendicular to the reference observation direction OBS1, relative to a vertical plane perpendicular to the reference observation direction OBS1. The second mirrors 412, 422 are disposed below the first mirrors. When the first optical element and the second optical element are in a first relative position, the tilted observation direction OBS2 corresponds to a downward looking direction of the subject's eyes.

[0118] 4 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 arranged side by side along the horizontal direction, partially facing each other.

[0119] 4, the first mirrors 411, 421 of the accessory device 2 are adapted to be tilted with respect to the reference observation direction OBS1. The first mirrors 411, 421 can be tilted toward the second mirrors 412, 422 at a tilt angle about a vertical axis perpendicular to the reference observation direction OBS1, relative to a vertical plane perpendicular to the reference observation direction OBS1. The second mirrors 412, 422 are disposed beside the first mirrors and closer to the other eye. When the first optical element and the second optical element are in a second relative position, the tilted observation direction corresponds to the convergence visual direction of the subject's eyes.

[0120] The above internal arrangements may be combined so that the oblique observation direction is downward and convergent.

[0121] It should be noted that the convergence observation direction can be obtained at least in part by rotating the refraction test elements 11, 12 of the optometric device 1 about 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 optometric device to the interpupillary distance of the subject's eyes. This is particularly useful when the interpupillary distance is smaller than the average interpupillary distance.

[0122] This case is shown in Figure 4, where the interpupillary 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 optometric device 1. The accessory device 2 makes it possible to perform subjective testing on eyes with such an interpupillary distance.

[0123] This is also useful when the accessory device introduces larger variations in the distance between the eye and the corresponding optical component.

[0124] The ratio between the convergence introduced by the accessory device 2 and the convergence introduced by the optometric device 1 may depend on the interpupillary distance of the subject, i.e., as the interpupillary distance increases, in other words, for people with a larger interpupillary distance, the optometric device introduces an increasing portion of the convergence.

[0125] When the interpupillary distance of the subject decreases, in other words, for people with a smaller interpupillary distance, the portion of convergence introduced by the optometric device decreases. Also, by using both the optometric device 1 and the accessory device 2 to obtain the convergence observation direction, it is possible to change the distance between the virtual images of the visual target without changing the configuration of the optical system of the accessory device.

[0126] This allows the optometry system 3 of the present invention to be used for any interpupillary distance value at 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.

[0127] 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 optometric device.

[0128] 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 shown schematically in FIG. 2 and described below.

[0129] Figures 2, 4 and 8 show the optical paths of the light rays emitted by the display unit 20 in a full straight line starting from the targets T1, T2 (Figure 4) or from the optical components 11A, 12A of the optometric device 1 to the subject's eye E1.

[0130] 2, 4, and 8 show the optical path of light when the accessory device 2 is in a configuration in which the light ray is deflected from the reference observation direction OBS1 by the first optical component 411, 421 of the accessory device 2. The optical path of the light ray initially extends along the optical axis OA1 of the optical component 11A of the optometric device 1, which is aligned with the reference observation direction OBS1. The light ray is reflected by the first mirror 411 towards the second mirror 421, which reflects the light ray along the final observation directions OBS2, OBS3 towards the pupil center of the subject's eye (FIGS. 2, 4, and 8).

[0131] In general, the center of rotation CRO1 of eye E1 can be advantageously aligned with the reference observation direction OBS1, and preferably aligned with both the reference observation direction OBS1 and the inclined observation directions OBS2, OBS3, to ensure switching from viewing the image of the target along the reference observation direction OBS1 to viewing the image of the target along the inclined observation directions OBS2, OBS3 by simply removing the first mirror 411 from the reference observation direction OBS1 without changing the position of the subject's eye.

[0132] 2, 4, and 8 show schematic diagrams of an equivalent straight-line path of light, represented by a dashed line. This equivalent straight-line path of light extends along the oblique observation directions OBS2 and OBS3. A virtual position VL of the optical component 11A along this equivalent straight-line path of light is shown by a dashed line. This virtual position VL is obtained by unfolding the path of light between the optical component and the subject's eye to trace the equivalent straight-line path of light (represented by the dashed line).

[0133] The optical vertex distances d2, 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, that is, this is the sum of, for example, the optical distance between the vertex of the eye's cornea along the optical path and the second mirror 412, the optical distance between the second mirror 412 and the first mirror 411 along the optical path, and the optical distance between the first mirror 411 and the vertex of the surface of the optical component 11A directed towards the eye.

[0134] This expanded representation of the optical paths in the optometric device 1 and the accessory device 2 makes it possible to visualize the optical vertex distance in the downward or convergence viewing direction configuration of the optometric system 3 corresponding to the values ​​of the above parameters in the downward or convergence viewing direction at the accessory device 2.

[0135] It can also be seen that the field of view is limited by the exit opening of the optometric device 1 and not by a mirror. The dash-dotted lines in Figures 2 and 4 indicate that the full range of optical components is visible through the accessory device 2.

[0136] Advantageously, in one embodiment shown in Figures 2, 3 and 5 to 8, the first optical elements 411, 412 are movable between the operating position, in which they are positioned in front of the exit opening of the optometric device 1, in other words in front of the optical components 11A, 12A, in the reference observation direction OBS1 of the optometric device 1 (Figures 2 and 8), and a second retracted position, in which they are positioned outside the reference observation direction OBS1 (Figures 3 and 7).

[0137] When the first optical elements 411, 412 are in the active position, the light beams exiting the optometric device are intercepted by the first optical elements 411, 412 and deflected towards the second optical elements 421, 422. The images of the targets are visible by the subject's eyes in oblique observation directions OBS2, OBS3. The subjective test can be performed in near or intermediate viewing conditions in downgaze and / or convergence viewing directions.

[0138] When the first optical elements 411, 412 are in the second retracted position, the light beam exiting the optometric device is not deflected by the accessory device, and the image target is visible by the subject's eye E1 in the reference observation direction OBS1 (FIG. 3). The subjective test can be performed in a horizontal forward viewing direction under distance vision conditions.

[0139] This mobility of the first optical element makes it possible to test the subject's eyes in the downward and / or convergence viewing directions OBS2 and OBS3 as well as in the horizontal forward viewing direction OBS1 without removing the entire accessory device 2 from the optometric device 1. Furthermore, subjective testing in distance and near or intermediate viewing conditions can be performed without moving the optometric device 1.

[0140] Thus, the two optical elements 411, 412, 421, 422 of each optical system 41, 42 are preferably arranged such that, in use, both the reference observation direction OBS1 and the oblique observation directions OBS2, OBS3 pass through the centers of rotation CRO1, CRO2 of the subject's eyes E1, E2. This allows subjective examinations in distance and near or intermediate vision conditions to be performed without moving either the refraction examination unit of the optometric device or the subject's head. This is made possible by taking into account a predetermined position of the subject's head, which is controlled, for example, by a position adjustment element of the optometric device.

[0141] Alternatively, the accessory device may have a fixed optical element, such as a non-movable fixed mirror, in which case the accessory device may be completely detached from the optometric device 1 for use in horizontal straight-on gaze. In this case, easily removable attachment means for the accessory device may ensure that tests in downgaze and / or convergence gaze as well as horizontal straight-on gaze can be performed reliably without moving the optometric device 1.

[0142] In the first and second variants of the accessory device 2 of the present invention, which are schematically represented in Figures 10 and 11, the two first optical elements 411, 412 of the two optical systems 41, 42 of the accessory device 2 extend in the same first plane, and the two second optical elements 421, 422 of the two optical systems 41, 42 of the accessory device 2 extend in the same second plane.

[0143] 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, which means that if the first optical elements are movable as described above, the two first optical elements 411, 412 move together.

[0144] In particular, in a first variant shown in Fig. 10, the reflective or semi-reflective surfaces of the two first optical elements 411, 412 may belong to a single part, for example a first single mirror. The reflective or semi-reflective surfaces of the two second optical elements 421, 422 may also belong to a single part, for example a second single mirror. The first single mirror forming the two first optical elements 411, 412 may be movable between a first position and a second retracted position, as described above.

[0145] This ensures that the optical path of light is the same for both eyes, allowing for precise alignment of the optical components of the optometric device, the optics of the accessory device, and the subject's eyes. The image of each target is seen by the corresponding eye, and fusion of the two images can occur without any alignment issues.

[0146] In practice, the error in the alignment of the mirrors should be less than 1°, preferentially less than 1', to ensure comfortable fusion and therefore accurate binocular vision of the target.

[0147] In a second variant shown in Fig. 11, the optical system 41, 41 is formed by separate first and second optical elements. However, the reflective or semi-reflective surfaces of the two first optical elements 411, 412 of the optical system 41, 42 are aligned in the same plane. They may, for example, comprise two coplanar mirrors. The reflective or semi-reflective surfaces of the two second optical elements 421, 422 may also be aligned in another plane, for example belonging to two different coplanar mirrors.

[0148] The relative positions and orientations of the two optical systems 41, 42 are fixed as a whole. The positions and / or orientations of the two first optical elements on the one hand and the two second optical elements on the other hand may be fixed or may only be varied together.

[0149] 12, the position and / or orientation of each optical system 41, 42 is adjusted so that the optical system 41, 42 remains aligned with the corresponding optical component 11A, 12A of the optometric device 1. The position and / or orientation of each optical system 41, 42 can be adjusted independently of the positions and / or orientations of the other optical systems 41, 42.

[0150] The relative positions and orientations of the first and second optical elements of each optical system 41, 42 are fixed except for the optional movability of the first optical element mentioned above.

[0151] In particular, each optical system 41, 42 can be rotated about an axis of rotation X1, X2 (FIG. 12) that is configured to be parallel to the axes of rotation V1, V2 of the optical refractive elements 11, 12 of the optometric device 11 when the accessory device 2 is attached to the optometric device 1.

[0152] In this case, when the optical systems 41, 42 are rotated to align with the convergence optical axes OA1, OA2 of the optical components of the optometric device 1, the accessory device preferably includes a software portion programmed to rotate the visual target displayed by the display unit 20 of the optometric device 1 symmetrically relative to both eyes to compensate for the periodic rotations undergone by each image of the visual target due to a combination of rotations imposed by reflections on the optical elements of the optical system of the accessory device. This will be explained in more detail below with reference to Figures 13 to 17.

[0153] The accessory device 2 is positioned between the exit openings of the optical refractive elements 11, 12 of the refraction examination unit 10 of the optometric device 1 and the subject's eye. The presence of the accessory device 2 therefore changes the physical and / or optical distance between the eye and the corresponding optical components 11A, 12A of the refraction examination unit. This physical and / or optical distance typically increases. As a result, the parameter describing the relative position of the subject's eye and the corresponding optical components 11A, 12A of the optical refractive elements 11, 12 of the optometric device 1 exhibits a final value that is different from, and in particular higher than, a reference value determined in the presence of the accessory device.

[0154] 2, 4 and 8 show the optical vertex distances d2, d3 with the first mirror in the actuated position in the presence of the accessory device.

[0155] 3 and 7 show the optical vertex distance d1 with the first mirror in the retracted position in the presence of an accessory device.

[0156] The size and orientation of the optical elements of each optical system 41, 42 of the accessory device 2 can be adjusted to minimize the optical distance between the subject's eye and the optical components 11A, 12A of the refraction examination unit 10 of the optometric device 1 when the accessory device 2 is attached to the optometric device 1.

[0157] In the example shown in Figures 2-4, the size and orientation of the two mirrors used as optical elements 411, 412, 421, 422 can be adjusted to minimize this optical distance.

[0158] In practice, the final value of the optical distance between the optical components 11A, 12A of the optometric device 1 and the subject's eye is comprised, for example, between 20 and 80 mm, preferentially around 50 mm.

[0159] Furthermore, the presence of the accessory device 2 may change the relative position and / or orientation of the subject's eyes E1, E2 and the image of the visual target seen by the subject's eyes.

[0160] The accessory device 2 may be attached to the optometric device 1 by any suitable means known to those skilled in the art, for example by being screwed, glued or attached by a magnet or any other mechanical means to the housing of the optometric device.

[0161] The accessory device 2 may be detachable or fixed to the optometric device 1. If detachable, easily removable attachment means may be used, such as snap fit means.

[0162] Two embodiments of the accessory device 2 are shown in Figures 5 to 8 and 9, respectively. As shown in Figures 5 to 9, in each embodiment, the optical portion 40 of the accessory device 2 comprises a housing 43 configured to be attached to the refraction testing unit 10 of the optometric device 1.

[0163] Each optical system is received in the housing 43 .

[0164] In practice, the housing 43 is attached to the optometric device 1. The housing 43 is preferably attached to the optometric device 1 in a fixed position where it cannot be moved.

[0165] Here, the housing 43 comprises two frames 43A, 43B having a generally rectangular outline (FIGS. 6 and 9), each of which is attached to one of the refractive test elements 11, 12 (FIGS. 5 and 9).

[0166] In the first and second embodiments of Figures 5-8 and 9, each frame 43A, 43B comprises an end wall 44 configured to be placed in contact with the optical refractive element 11, 12 of the optometric device. The end wall 44 comprises holes 44A, 44B that allow light rays to enter the accessory device 2. Lateral walls 45 surround the end wall on three sides.

[0167] The lateral wall 45 of each frame 43A, 43B includes two parallel side walls 451 that extend along the longitudinal axis L1 of the accessory device 2. The longitudinal axis is configured to be vertical when the accessory device 2 is in use.

[0168] The longitudinal axis L1 of the accessory device is configured to extend parallel to the rotation axes V1, V2 of the optical refractive elements 11, 12 of the optometric device 1.

[0169] The two frames 43A, 43B are united by a horizontal bar that extends perpendicular to the side walls.

[0170] The side walls 451 of each frame 43A, 43B are connected by a bottom wall 452 extending perpendicularly to the side walls 451.

[0171] The inner surface of the bottom wall 452 of each frame 43A, 43B is angled toward the subject about a transverse axis perpendicular to the longitudinal axis of the accessory device, and supports a reflective surface that forms the second optical element 412, 422 of each optical system.

[0172] In both embodiments, a flap 46 extends from one frame to the other. The flap 46 is attached to the side wall of the frame on a rotation axis Y (FIGS. 6 and 9). The rotation axis Y is approximately horizontal. The rotation axis Y is parallel to the two reflecting surfaces 411, 412, 421, and 422 of each optical system.

[0173] The flap 46 comprises two coplanar elements of the flap, each attached to the interior of one of the two frames 43A. The elements are connected by a bridge 46B with a recess 46A at its leading edge. The recess 46A is provided so that the subject's nose extends between the two frames (FIGS. 6 and 9).

[0174] The face of the flap 46 facing the bottom wall 452 may comprise a single reflective surface extending across the flap, or two separate reflective surfaces positioned corresponding to the bottom wall 452 and forming the first optical elements 411, 421.

[0175] When the bridge 46B of the flap 46 abuts the side walls of the frames 43A, 43B, the first optical elements 411, 421 are in the operative position (FIGS. 5, 6 and 9).

[0176] To place the flap 46 in the retracted position, the flap 46 is pivoted upward about the axis of rotation Y and is immobilized in this pivoted position (FIG. 7).

[0177] An example of this implementation corresponds to the case shown in FIG. 11, where the reflective surfaces of the first optical element of the optical system are coplanar and the reflective surfaces of the second optical element are also coplanar.

[0178] The accessory device 2 also comprises two L-shaped arms 47 for attaching the housing 43 to the optometric device 1. The arms 47 extend in a common mean plane.

[0179] Each of the frames 43A and 43B is connected to one of the arms 47.

[0180] Each arm 47 includes a longitudinal portion extending along the longitudinal axis L1 of the accessory device 2 and a transverse end portion. The transverse end portions of the arms 47 extend away from each other. Each of the transverse end portions here includes a plate 48 whose shape corresponds to the contour of a corresponding portion of the support 13 of the optically refractive elements 11, 12 of the optometric device 1. Each plate 48 includes a magnet configured to interact with said corresponding portion of the support 13 of the optically refractive elements 11, 12 of the optometric device 1 in order to attach the accessory device to the optometric device. In practice, to attach the accessory device, the cover panel of the support 13 is removed and replaced with the plate 48.

[0181] In a second embodiment of the accessory device shown in Figure 9, the accessory device 2 further comprises image capturing means 50 for capturing a profile image of the subject's eye.

[0182] The image capturing means 50 includes sensors 56, such as cameras, each configured to capture a profile image of one of the subject's eyes. Each sensor 56 is part of a printed circuit board 55 that is powered through conductors 57. Each printed circuit board 55 is supported by a base 51. The base 51 includes a first branch extending from the side wall of the frames 43A, 43B of the housing 43 of the optical portion 40 of the accessory device 2, parallel to the common mean plane of the arms 47. The base 51 also 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 that receives the printed circuit board 55. Thus, the two printed circuit boards face each other and extend parallel to each other.

[0183] Advantageously, the accessory device 2 also comprises a determination tool 31 configured to determine a vision-correcting refractive power for the subject's eye, taking into account the refractive power provided by the refraction examination unit 10 during the subjective refraction examination and the final values ​​of parameters representative of the relative position of the eye and the optical components 11A, 12A of the optometric device 1 in the presence of the accessory device 2.

[0184] The determination tool provides the vision-correcting refractive power of the subject's eye taking into account the new optical path of the light through the accessory device, so that an accurate value of the vision-correcting refractive power can be determined by the system comprising the optometric device and the accessory device.

[0185] In practice, the determination tool 31 comprises a software portion programmed to calculate the vision correction refractive power depending on the final values ​​of the parameters representing the relative positions of the subject's eye and the optical components 11A, 12A of the optometric device 1, determined, for example, in the presence of the accessory device 2.

[0186] The software part may be configured to be implemented by the above-mentioned control device 30 of the optometric device. The decision tool 31 is represented as part of the control device 30 in Figures 2 and 3 .

[0187] The determination tool may be software uploaded to the control device, in which case the determination tool is capable of calculating vision-correcting refractive power based on refraction measurements taken in the presence of the accessory.

[0188] The determination tool may also calculate the vision-correcting refractive power based on the reference vision-correcting refractive power and the final values ​​of the above parameters that describe the relative positions of the subject's eye and the optical components 11A, 12A of the optometric device 1. The determination tool may also take into account the reference values ​​of the above parameters that describe the relative positions of the subject's eye and the optical components 11A, 12A of the optometric device 1.

[0189] The accessory device 2 may also include an adjustment tool 32 that adjusts the position and / or orientation of each of the targets T1, T2 displayed by the display unit 20 based on the inclination of the inclined observation directions OBS2, OBS3, and / or adjusts the refractive power of the optical components 11A, 12A of the optometric device 1 based on the value of a parameter representing the relative position between the image of the target T1, T2 unit and the subject's eyes E1, E2.

[0190] The adjustment tool 32 may include software that may also be implemented by the control device 30 of the optometric device 1 .

[0191] In a variant, the determination tool and / or adjustment tool may be implemented by one or more processors different from the processor of the control device of the optometric device.

[0192] The vision correction refractive power VCP determined by the determination tool 31 takes into account the refractive powers of the optical components 11A, 12A of the optometric device 1 used during subjective testing, and the final values ​​of parameters representing the relative distance between the eye and the optical components when the optometric system 3 comprising the accessory device 2 is used for subjective testing in distance vision conditions (Figure 3) or near or intermediate vision conditions (Figures 2 and 4).

[0193] In one embodiment, the determination tool is programmed to determine a reference vision correction refractive power VCP(d0) for a reference value of vertex distance d0 based on the refractive power of SPH(di) provided by the optical components 11A, 12A when positioned at a working optical vertex distance equal to di, using the following basic formula:

number

[0194] In the above equation, - the working optical vertex distance di, in millimeters, which corresponds here to the final value of the parameter describing the relative position between the eye and the optical components of the optometric device, and in the examples shown in the drawings, di can be equal to d1, d2 or d3, Pobj is the reciprocal of the physical distance, in diopters, between the vertex of the surface of the optical component 11A in its virtual position VL directed towards the subject's eye and the image I1 of the target T1 as seen by the eye through the optical component of the optometry, e.g., 40 cm and equal to 2.5 D; - SPH(di) is the refractive spherical power of the optical component in diopters when the subject's eye is placed at the working vertex distance di during subjective testing, the refractive power of the optical component being calibrated for an object at infinity; - d0 is the reference value of the optical vertex distance in millimeters that corresponds to the recommended optical vertex distance without accessories.

[0195] The nominal value for the optical vertex distance is usually equal to 12 mm, which is similar to the average distance between the eye and the ophthalmic lens worn by the subject.

[0196] The working optical vertex distance di is, in the illustrated example, equal to d1 when the first mirror is in the retracted position (FIG. 3) and equal to d2 or d3 when the first mirror is in the actuated position (FIGS. 2 and 4).

[0197] In the retracted and actuated positions of the first mirror, the optical vertex distances d1, d2, d3 may be measured or may be estimated, for example, from a profile image of the eye looking through an optical system 3 whose internal geometry in each of the retracted and actuated positions of the first mirror is predetermined, fixed, and known.

[0198] In summary, for a myopic eye, the optical components 11A, 12A of the optometric device 1 include diverging lenses. When the diverging lenses of the optometric device 1 are spaced apart from the subject's eyes E1, E2 by a working optical vertex distance di that is greater than the reference value d0 of the optical vertex distance s, the diverging lenses that provide adequate vision correction at the working optical vertex di, as determined by subjective refraction, exhibit a reduced focal length compared to the focal length of the diverging lenses that provide adequate vision correction at the reference value of the optical vertex distance.

[0199] Thus, the absolute power value of a diverging lens that provides adequate vision correction at the working optical vertex distance di is greater than the absolute power value of a diverging lens that provides adequate vision correction at the reference value of the optical vertex distance.

[0200] In the case of a hyperopic eye, the optical components of the optometric device include a convergence lens. When the convergence lens of the optometric device is spaced from the subject's eye by a working optical vertex distance di that is greater than the reference optical vertex distance, e.g., equal to 12 millimeters, the convergence lens that provides adequate vision correction at the working optical vertex distance di exhibits a longer focal length compared to the focal length of the convergence lens that provides adequate vision correction at the reference optical vertex distance. Thus, the absolute power value of the convergence lens that provides adequate vision correction at the working optical vertex distance di is smaller than the absolute power value of the convergence lens that provides adequate vision correction at the reference optical vertex distance.

[0201] The reference vision correction refractive power for the subject's eye corresponds to the refractive power of the diverging and / or convergent lenses used in the optometric device without any accessory devices, determined through subjective refraction testing using a reference value d0 of the optical vertex distance.

[0202] In the case of astigmatism, the above basic formula applies to a first power value P1 equal to the spherical power SPH, and a second power value P2 equal to the spherical power SPH plus the cylindrical power CYL: P2=SPH+CYL.

[0203] This formula is only correct for objects at infinity, since optometric devices use optical components with a calibrated refractive power at infinity, which corresponds to Pobj = 0D in the above formula. At any other distance, this formula is accurate only for the thin lens approximation.

[0204] The optometric device 1 is programmed to provide a reference vision correction refractive power that corresponds to the observation of a target placed at infinity from the subject's eye in the absence of any accessory device.

[0205] Thus, the refractive power provided or displayed by the optometric device 1 without the accessory device 2 typically corresponds to the posterior vertex power calculated for a target at infinity.

[0206] In one embodiment of the accessory of the present invention, the determination tool 31 is configured to determine the vision-correcting refractive power depending on the value of a parameter describing the relative position of the image of the target and the subject's eye. The determination tool 31 is also advantageously configured to take into account the exact geometrical shape and / or optical properties of the optical components 11A, 12A of the optometric device 1.

[0207] In fact, more accurate calculations can be achieved by ray tracing and accurate description of the optical system geometry, as will be described below in an example of implementation of the present invention in a subjective test performed in near viewing conditions using the optometric system of the present invention.

[0208] The optical vertex distance between the eye and the optical components 11A, 12A of the optometric system 3 is equal to d2 (Fig. 2) or d3 (Fig. 4), taking into account the optical path of light through the accessory device 2. The distance between the rear surface of the optical component 11A, located at the virtual position VL, and the virtual image of the target is typically 40 cm. The refractive power provided by the optometric device corresponds to the rear vertex power calibrated for a target at infinity.

[0209] The determination tool is then programmed to simulate the optical components 11A, 12A of the optometric device 1 that provide the refractive power, calculate an image of a virtual target through the optical components 11A, 12A using a ray tracing method, and calculate a reference vision correction refractive power from the values ​​of parameters representing the relative positions of the subject's eye and the optical components 11A, 12A of the optometric device (here, the optical vertex distances are d2, d3 and the reference value of the optical vertex distance is d0).

[0210] To simplify the calculations of the ray tracing method, the corneal apex of eye E1 and the center of rotation of the eye are virtually positioned at an optical vertex distance d2 from the rear surface of optical component 11A in the reference observation direction OBS1 of the optical component 11A of the optometric device 1, and the object point is positioned at a distance from the rear surface of optical component 11A equal to the distance between the rear surface of virtual position VL of optical component 11A directed toward eye E1 in the reference observation direction OBS1 and the center of virtual image I1 of visual target T1 seen through accessory device 2.

[0211] The elements of the simulation are shown schematically in Figure 18. The virtual position of eye E1 is defined by the position of its corneal apex C1 and its center of rotation CRO1.

[0212] Points J and J' represent two distinct positions of the vertex of the posterior surface of optical component 11A directed toward eye E1. Point J represents the actual position of the vertex of the posterior surface of optical component 11A directed toward eye E1 when the optical vertex distance is equal to d2, d3, and point J' represents the theoretical position of the vertex of the posterior surface of optical component 11A directed toward eye E1 when the optical vertex distance is equal to the reference value of the optical vertex distance. Here, the optical vertex distance is defined as the optical distance between the vertex C1 of the cornea of ​​eye E1 and the vertex (denoted as J or J') of the optometric device's optical component 11A.

[0213] The actual optical vertex distances d2, d3 between the eye E1 and the optical component 11A of the optometric device are longer than the reference values.

[0214] Points M and M' on the reference observation direction OBS1 represent two corresponding real and theoretical object points. The distance MJ, M'J' remains fixed and equal to the distance between the rear surface of the optical component 11A at a virtual position VL directed toward the eye E1 and the virtual image I1 of the target T1 as seen through the accessory device of Figure 4.

[0215] The refractive power obtained from the optometric device 1 at the end of the refraction test is used to estimate the properties of an optical model corresponding to the optical component 11A or the properties of the optometric device 1 used without the accessory device 2. If the optical component 11A comprises a continuously deformable lens, its shape can be optimized taking into account the refractive power provided by the optometric device 1 and a target placed at infinity.

[0216] Sagittal focus S corresponding to point M F and tangential focus T F is calculated by ray tracing using an optical model reflecting the properties of the optical component 11A estimated from the refractive power of the optometric device 1 obtained at the end of the refraction test.

[0217] The determination tool then determines the sagittal focus S F and tangential focus T F and the distance JS between the actual position J of the optical component 11A. F , J.T. F Calculate.

[0218] Then, the reference visual correction refractive power (VCP(d0)) corresponding to the reference value d0 of the optical vertex distance is calculated by the distance M'J' between the object point and the rear surface of the optical component of the optometric device at the theoretical positions M', J', where M'J'=MJ, and the distance J'S between the optical component of the optometric device at the theoretical position and the sagittal and tangential foci. F ,J'T F It is calculated based on the

[0219] For example, the spherical equivalent reference visual correction refractive power VCP and astigmatism VCAST are calculated by the following equations. VCP(d0)=1 / M'J'+0.5*(1 / J'S F +1 / J'T F ) VCAST(d0)=1 / J'S F -1 / J'T F however, J'S F =J'SF +di-d0 J'T F =J'T F +di-d0 In the above equation, di=d2 or d3.

[0220] This formula may be used to determine the vision correcting power, which may be spherical power, equivalent spherical power, cylindrical power, or astigmatism.

[0221] When the virtual image of the target is considered, the above-mentioned distances MJ, M'J', J'S F , and J'T F is a signed algebraic value.

[0222] In one embodiment, the distance between the subject's eyes E1, E2 and the optical components 11A, 12A of the optometric device 1, in particular the optical vertex distance, is measured using image capture means such as that described with reference to Figure 9 above. The camera is positioned so as to be configured to capture an image indicative of the subject's eye. The image capture means also comprises means for determining the distance between the camera and the optical components of the optometric device.

[0223] Alternatively, the camera is positioned so as to be configured to capture images showing the subject's eye and the optical components of the optometric device.

[0224] In another variation, the camera includes a time-of-flight camera.

[0225] Alternatively, the distance between the subject's eye 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 optometric device.

[0226] In another example of implementation of the present invention, the determination tool may comprise a database containing data related to the vision-correcting refractive power of the subject's eye linked to values ​​of the parameters representative of the relative positions of the subject's eye and the optical components of the optometric device determined in the presence of the accessory device. The database may also contain data related to the vision-correcting refractive power of the subject's eye linked to the refractive powers of the optical components of the optometric device, in particular the refractive powers obtained in the last step of the subjective test, which correspond to the optimal vision correction of the visual defect of the subject's eye.

[0227] The database may contain tables or graphs. In this case, the vision-correcting refractive powers fitted to the subject's eyes can be read on the database taking these data into account. Examples of such databases are shown in Tables 1 to 3 below.

[0228] The vision correction refractive power corrected to fit the above-mentioned target distance of 12 mm between the eye and the ophthalmic lens based on the spherical refractive power (Rxsph) values ​​of the optical components 11A and 12A obtained in the last step of the subjective test under near vision conditions, and the actual optical vertex distance between the cornea of ​​the eye and the optical component (d2) of the optometric device are shown in Table 1 below for the image of the target placed 40 cm from the rear surface of the optical component.

[0229] [Table 1]

[0230] The difference between the vision-correcting refractive power thus determined and the vision-correcting refractive power calculated without correction by the prior art optometry device 1 is shown in Table 2 below.

[0231] [Table 2]

[0232] 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 optometric device 1 obtained in the last step of the subjective test, when an object is placed 40 cm behind the optical components 11A, 12A of the optometric device 1 and the distance between the eye and the ophthalmic lens is 12 mm.

[0233] [Table 3]

[0234] The presence of accessory device 2 may also change the relative position of the subject's eyes and the images of the visual targets they see. In particular, the deflection introduced to provide convergence viewing means that virtual images I1, I2 of visual targets T1, T2 are perceived by the subject's eyes E1, E2 at near viewing distances (FIG. 4).

[0235] To also create an accommodation need related to the proximity position of the virtual image of the target, the refractive power of the optical components 11A, 12A of the optometric device 1 may be adjusted by the value Pscreen-Pobj, where Pscreen is the actual proximity of the displayed target (close to 0 or 0.2D for a distance of 5 m) and Pobj is the target proximity of the virtual image of the target (2.5D, i.e. 40 cm for near vision). Proximity is equal to the reciprocal of the distance.

[0236] The adjustment tool 32 of the accessory device 2 may then include a software portion programmed to adjust the refractive power of the optical components 11A, 12A of the optometric device 1.

[0237] The adjustment tool 32 of the accessory device 2 may also include a software portion programmed to adjust the position and / or orientation of each of the targets T1, T2 displayed by the display unit 20 based on the tilt angle of the tilted observation directions OBS2, OBS3, as described above.

[0238] This adjustment is determined to ensure that the images I1', I2' of the targets T1, T2 seen by the subject's eyes present a predetermined position and / or orientation.

[0239] In particular, each set of first optical elements 411, 412 and second optical elements 421, 422 may be rotated about rotation axes X1, X2 (FIG. 12), which are configured to be parallel to rotation axes V1, V2 of the optical refractive elements 11, 12 of the optometric device 1 when the accessory device 2 is attached to the optometric device 1.

[0240] As a result, when the optical refractive elements 11, 12 of the optometric device 1 are rotated about their rotation axes V1, V2, the corresponding sets of first and second optical elements can be rotated to maintain precise alignment of all optical components, particularly when an accessory device is used to provide an oblique viewing direction corresponding to a vergence viewing direction.

[0241] 12, when the positions and / or orientations of the above optical systems are adjusted independently of each other, the position and orientation of the visual target displayed by the display unit 20 must be adapted to the orientation of the subject's gaze direction, as explained below. Indeed, when the first and second optical elements 411, 422, 421, 422 of both optical systems for both eyes are not in the same plane, the visual target seen by each eye of the subject is rotated around the oblique observation direction. Preferably, in this case, the adjustment tool 32 of the accessory device includes software portions programmed to rotate the visual target symmetrically for each eye to compensate for the circular rotation each image undergoes due to the combined rotations caused by the mirrors of each optical system 41, 42.

[0242] FIG. 13 shows an example of targets T1, T2 displayed by the display unit 20 of the optometric device without any adjustment.

[0243] FIG. 14 shows a schematic representation of two images I1, I2 of the above-mentioned targets T1, T2 as seen by both eyes of a subject looking through the accessory device 2 and the optometric device 1 in the configuration of FIG.

[0244] The 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 which is directed to one of the subject's eyes. Rotation of the optical elements of the accessory device 2 causes the images I1, I2 of the visual targets T1, T2 to rotate. Figure 14 schematically shows the images I1, I2 of the visual targets as seen by each eye of the subject.

[0245] Figure 15 shows the superposition of two images I1 and I2 of a visual target seen by a subject with binocular vision. The subject cannot see a clear image as shown in Figure 15, and fusion of the two images I1 and I2 of the visual targets T1 and T2 cannot occur because they cannot be superimposed.

[0246] The position and orientation of the targets T1, T2 generated by the display unit 20 position and orientation should then be adapted so that both images I1', I2' of the targets reflected by the accessory device 2 are accurately superimposed.

[0247] FIG. 16 shows the corrected targets T1' and T2' displayed by the display device.

[0248] The corrected targets T1', T2' are oriented so that the images I1', I2' of the corrected targets are accurately superimposed on the subject's binocular vision, as shown in FIG.

[0249] In practice, the correction involves rotating the initially displayed targets T1, T2 for each eye by a correction angle value Acorr, which is calculated based on the values ​​of the convergence angle A2 and the downturn angle A1 of the oblique observation direction acquired by the accessory device 2 according to the following formula: Acorr=A2*sin(A1)

[0250] By using the accessory device 2 together with the optometric device 1, it becomes possible to move the gaze direction of the subject's eyes downward without changing the position of the optometric device 1, particularly the refraction testing unit 10.

[0251] This solution has many advantages: - when switching from a forward looking direction for distance refraction testing to a downward looking direction for near refraction testing using the optometric device 1, neither the position or orientation of the optometric device nor the position and / or orientation of the subject's head need to be changed; - Accessory devices are simple and lightweight add-on devices, the accessory device may be configured for use with any type of optometric device; The use of the accessory device makes it possible to perform near vision tests using the comfortable ergonomics of the optometric device, which does not rest against the subject's cheekbones while performing the near vision test.

[0252] The accessory device 2 can also be used to create a convergence between two gaze directions. This solution has the following advantages: - when switching from distance vision refraction to near vision refraction, no adjustment of the optometric device, in particular adjustment of the relative position and / or orientation of the refraction test elements 11, 12 of the refraction unit 10, is required; - Avoiding the limitations of small interpupillary distances in near viewing conditions, as shown in Figure 4, The optometric device makes it possible to perform subjective refraction tests for any viewing distance between distance and near viewing conditions on the same display device.

[0253] The optometric device described herein is a conventional optometric device used in subjective refraction testing to determine the refractive characteristics of a subject's eye, and the accessory device is used to determine the refractive characteristics of the subject's eye.

[0254] Alternatively, the accessory device may be used with the same King optometry device or any other corresponding optometry device to test various characteristics of the subject's eye, such as visual performance, eye dominance, vergence, strabismus, objective or subjective characteristics of the subject's eye, etc. [Explanation of symbols]

[0255] 1 Refraction Test Unit 2 Accessory Devices 3. Optometry System 10 Refraction Test Unit 11 First optical refractive element 12 Second optical refractive element 13 Support 14 Support structure 15 Position adjustment element 20 Display Unit 30 Control Device 31 Decision Tools 32 Adjustment Tools 40 Optical part 41 Optical system 42 Optical system 43 Housing, frame 44 End Wall 45 Side Wall 46 Recess 47 Arm 48 Plates 50 Image capture means 51 First branch, base 52 Second Branch 54 Receiving plate 55 Printed Circuit Board 56 Sensors 57 Conductor

Claims

1. An accessory device (2) for testing a subject's eyes (El, E2) in near or intermediate vision conditions, designed to be used with an optometric device (1) for measuring the subjective refraction of the eyes (El, E2), the accessory device (2) comprising: a refraction test unit (10) having optical components (11A, 12A) for providing different refractive powers to the eyes (E1, E2) of the subject during a subjective refraction test; a display unit (20) adapted to generate visual targets (T1, T2) for the eyes (E1, E2) of the subject, wherein images of the visual targets (T1, T2) are visible through the refraction test unit (10) along a reference observation direction (OBS1); Equipped with the accessory device (2) comprises an optical part (40) configured to be attached to the refraction test unit (10) of the optometric device (1), the optical part (40) comprising optical systems (41, 42) configured to shift the image of the visual target (T1, T2) from the reference observation direction (OBS1) toward oblique observation directions (OBS2, OBS3) along which the image of the visual target (T1, T2) is visible through the refraction test unit (10) and the optical part (40) of the accessory device (2), the oblique observation directions (OBS2, OBS3) defining non-zero angles (A1, A2) with the reference observation direction (OBS1) when the optical part (40) is attached to the refraction test unit (10) of the optometric device (1), and corresponding to the subject's downward gaze direction and / or the subject's convergence gaze direction.

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

3. 2. The accessory device (2) of claim 1, wherein the optical system (41, 42) comprises two optical elements (411, 412, 421, 422), a first optical element (411, 421) of the two optical elements being arranged in an operating position in front of the exit opening of the optometric device (1) and configured to shift the image of the visual target (T1, T2) and transmit it to a second optical element (412, 422) of the two optical elements, and the second optical element (412, 422) being configured to shift the image of the visual target along the oblique observation direction (OBS2).

4. 4. The accessory device (2) of claim 3, wherein the first optical element (411, 421) is movable between the operating position in which it is positioned in front of the optical components (11A, 12A) of the ophthalmic device (1) in the reference observation direction (OBS1) and a second position in which it is positioned outside the reference observation direction (OBS1).

5. 2. The accessory device (2) of claim 1, comprising a determination tool (31) configured to determine a vision-correcting refractive power for the eye (E1, E2) of the subject, taking into account final values ​​of parameters representative of the relative positions of the eye (E1, E2) and the optical components (11A, 12A) of the optometric device (1) in the presence of the accessory device (2).

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

7. 2. The accessory device of claim 1, wherein the determination tool (31) includes a software portion programmed to calculate the vision-correcting refractive power.

8. 8. The accessory device according to claim 7, wherein the optometric device (1) comprises a control device (30) programmed to determine a reference vision-correcting refractive power for the eyes (E1, E2) of the subject, taking into account the refractive power provided to the eyes (E1, E2) of the subject by the refraction examination unit (1) and reference values ​​of parameters representing the relative positions of the eyes (E1, E2) and the optical components (11A, 12A) in the absence of the accessory device (2), and wherein the software portion is configured to be implemented by the control device (30) of the optometric device (1).

9. 2. The accessory device according to claim 1, further comprising an adjustment tool (32) configured to adjust the position and / or orientation of each visual target displayed by the display unit based on a tilt of the tilt observation direction and / or to adjust the refractive power of the optical components (11A, 12A) of the optometric device (1) based on values ​​of parameters representing the relative positions of the images of the visual targets (T1, T2) and the eyes (E1, E2) of the subject.

10. 2. The accessory device of claim 1, wherein the determination tool comprises a database containing data related to the vision-correcting refractive power for the eye of the subject linked to a magnitude value representing the relative position of the eye of the subject and the optical components of the optometric device determined in the presence of the accessory device.

11. 2. The accessory device of claim 1, wherein the optical portion (40) comprises a housing (43) in which the optical systems (41, 42) are housed, and the housing (43) is configured to be attached to the refraction testing unit (10) of the optometric device (1).

12. The refraction examination unit (10) of the optometric device (1) has two optical components (11A, 12A) for providing different refractive powers to both eyes (E1, E2) of the subject, and the optical part (40) of the accessory device (2) includes two optical systems (41, 42), each of which is configured to be disposed in front of one of the two optical components (11A, 12A) of the optometric device (1), thereby examining the eyes (E1, E2) of the subject with binocular vision.

4. The accessory device of claim 3, wherein each optical system (41, 42) comprises the first and second optical elements (411, 412, 421, 422), the two first optical elements (411, 421) extending in the same first plane, the two second optical elements (412, 422) extending in the same second plane, and the relative position and / or orientation of the two first optical elements (411, 421) and the relative position and / or orientation of the two second optical elements (412, 422) being fixed.

13. 4. The accessory device of claim 3, wherein the refraction examination unit (10) of the optometric device (1) has two optical components (11A, 12A) for providing different refractive powers to both eyes (El, E2) of the subject, the optical part (40) of the accessory device (2) comprises two optical systems (41, 42), each of which is configured to be positioned in front of one of the two optical components (11A, 12A) of the optometric device (1) to enable binocular examination of the eyes (El, E2), and each optical system comprises the first and second optical elements (411, 412, 421, 422), and the positions and / or orientations of the first optical elements (411, 421) of the optical systems are adjustable independently of each other, and the positions and / or orientations of the second optical elements (412, 422) of the optical systems are adjustable independently of each other.

14. 10. An optometry system comprising an accessory device (2) for examining an eye of a subject in an ergonomic condition for near or intermediate vision and an optometry device (1) for measuring the subjective refraction of the eye according to claim 1, wherein the optometry device (1) comprises: a refraction testing unit (10) having optical components (11A, 12A) for providing different refractive powers to the eyes (E1, E2) of the subject; a display unit (20) adapted to generate visual targets (T1, T2) for the eyes (E1, E2) of the subject, wherein images of the visual targets (T1, T2) are visible through the refraction testing unit (10) of the optometric device (1) along a reference observation direction (OBS1); Equipped with An optometry system, wherein the optical portion (40) of the accessory device (2) is attached to the refraction testing unit (10).

15. 15. A method for testing a subject's eye in distance and near or intermediate vision conditions using the optometry system of claim 14, the method comprising: performing a visual acuity test under a distance viewing condition, while the subject observes the image of the optotype (T1, T2) displayed by the display unit (20) of the optometric device (1) along the reference observation direction (OBS1) that is not displaced by the accessory device (2); Using the accessory device (2), displace the image of the visual target (T1, T2) towards the oblique observation direction (OBS2, OBS3); performing a visual acuity test in near or intermediate vision conditions, without moving the refraction test unit (10) between performing the visual acuity test in far vision and performing the visual acuity test in near or intermediate vision, while the subject observes the image of the visual target (T1, T2) displayed by the display unit (20) of the optometric device (1) and displaced by the accessory device (2) along the oblique observation direction (OBS2, OBS3); A method comprising:

Images