Method for determining accurate values ​​of refractive properties of a subject's eye in near and / or intermediate viewing conditions - Patents.com

Abstract

The present invention relates to a method of using an optometry device having a refraction testing unit with a first optical refractive element adapted to provide different vision correction powers to a first eye of a subject along a first optical axis and a second optical refractive element adapted to provide different vision correction powers to a second eye of the subject along a second optical axis, the method comprising the steps of: a) adjusting (100) a relative position of the subject and the refraction testing unit; b) determining (200) a vertex distance between the first or second optical refractive element and the first or second eye of the subject; and c) determining (300) a value of a parameter representative of an accommodation characteristic of the eye of the subject. a) determining (400) preliminary values ​​of the refractive properties of the subject's eyes in near and / or intermediate vision conditions; e) checking (500) the binocular vision perception of the subject; f) determining (600) the final visual acuity of the subject; and g) determining (700) the exact values ​​of the refractive properties of the subject's eyes in near and / or intermediate vision based on the results of the previous steps, wherein in step d) the following steps are performed in this order: measuring a first value of the spherical refraction of each eye of the subject; measuring the preliminary value of the cylindrical refraction of each eye; and measuring a second value of the spherical refraction of each eye of the subject.

Description

[Technical field]

[0001] The present invention relates to a method for determining accurate values ​​of the refractive properties of a subject's eye in near and / or intermediate viewing conditions.

[0002] This method may in particular be used in a method for determining the complete set of values ​​of the refractive properties of a subject's eye. [Background technology]

[0003] Known devices and methods for binocular testing of a subject's eyes are usually dedicated to testing the eyes in distance viewing conditions, where the images shown to the subject to test binocular distance vision are usually positioned more than one meter away from the subject's eyes.

[0004] However, the refractive properties of the eye in near and / or intermediate viewing conditions may differ from those in distance viewing, which may be due, among other things, to different accommodation and convergence of the eye in near and / or intermediate viewing conditions. Summary of the Invention [Means for solving the problem]

[0005] It is therefore an object of the present invention to provide a new method which allows to accurately determine the refractive properties of a subject's eye in near and / or intermediate viewing conditions. In particular, the new method proposed allows to determine the refractive properties of a subject's eye in near and / or intermediate viewing conditions while keeping both of the subject's eyes open.

[0006] The object is to provide a method for determining accurate values ​​of the refractive properties of an eye of a subject in near and / or intermediate vision conditions using an optometry device having a refraction test unit with a first refractive optical element adapted to provide different vision correction powers to a first eye of the subject along a first optical axis and a second refractive optical element adapted to provide different vision correction powers to a second eye of the subject along a second optical axis, the method comprising: The following steps: a) adjusting the relative positions of the subject and the refraction testing unit such that the pupil of the subject's eye is aligned with the first optical axis and the second optical axis in near and / or intermediate vision conditions; b) determining a vertex distance between the first or second optical refractive element and the first or second eye of the subject in near and / or intermediate viewing conditions; c) determining values ​​of parameters representative of the accommodation properties of the subject's eye in near and / or intermediate viewing conditions; d) determining preliminary values ​​of the refractive properties of the subject's eyes in near and / or intermediate viewing conditions, including at least a preliminary value of the spherical power of each eye in the near and / or intermediate viewing conditions and a preliminary value of the cylindrical power of each eye in the near and / or intermediate viewing conditions; e) checking the subject's binocular vision perception by adding a predetermined additional spherical power to the vision correction provided to the eye; f) determining the subject's final visual acuity in near and / or intermediate viewing conditions; g) determining said accurate values ​​of the refractive properties of the subject's eye in near and / or intermediate vision based on the results of the previous step; Including, In said step d), the following steps are carried out: - measuring a first value of spherical refraction in each eye of the subject; - measuring said preliminary value of cylindrical refraction for each eye; - measuring a second value of the spherical refraction of each eye of the subject, the preliminary value of the spherical refraction of each eye of the subject being determined based on the second value; are performed in this order: This is achieved according to the present invention by providing a method.

[0007] This particular sequence of steps allows for rapid, yet accurate, determination of both the spherical and cylindrical refractive characteristics of a subject's both eyes in near and / or intermediate viewing conditions.

[0008] The method of the present invention is preferably applied to each eye to determine characteristics of both eyes.

[0009] The refractive properties include at least one of the following: spherical refraction, cylindrical refraction, and axial.

[0010] In the following, the near vision condition corresponds to a distance between the subject's eye and the visual target that is equal to or less than 50 cm, preferably included between 25 and 50 cm. The intermediate vision condition corresponds to a distance between the subject's eye and the visual target that is greater than 50 cm and equal to or less than 100 cm, preferably included between 50 and 100 cm. In the near and intermediate vision conditions, the line of sight of the subject's eye may be straight ahead, nearly horizontal, or inclined downwards, preferably at an angle between 10 and 50 degrees, relative to the horizontal.

[0011] These distances are achieved by a display system of the optometric device which allows displaying a visual target at a predetermined distance from the first and second optical refractive elements of the refraction testing unit.

[0012] According to another advantageous and non-limiting feature of the method of the present invention, - in step a) a camera aimed at the subject's eyes, an eye tracking device or a support for the subject's head is used, - in step b), at least a profile image of a subject positioned in front of the refraction test unit is acquired, from which a distance between each eye and a corresponding optical refraction test element is estimated, - before step d), a preliminary visual acuity test of the subject's eye is carried out, with the initial sphere and / or cylinder power and axis of each optical refractive element being determined based on the refractive properties of the subject's existing optical device or on the refractive properties of the subject's eye in distance vision conditions, - in step c), a binocular accommodation test is performed by presenting to each eye of the subject an identical target located at a near or intermediate vision optical distance from the eye of the subject, modifying the spherical power of each of the first and second optical refractive elements, and determining the minimum spherical power of the first and second optical refractive elements for the subject to accommodate to the target, - each of the steps of measuring the first value of spherical refraction for each eye of the subject, measuring the preliminary value of cylindrical refraction for each eye, and measuring the second value of spherical refraction is performed by testing both of the subject's eyes simultaneously with binocular vision or by testing each of the subject's eyes separately from the other while maintaining binocular vision; - the first value and the second value of the spherical refraction of each eye of the subject are determined by simultaneously testing both eyes binocularly; or - the first value of the spherical refraction of each eye of the subject is determined by testing both eyes simultaneously in binocular vision, and the second value of the spherical refraction of each eye of the subject is determined by testing each eye separately from the other while maintaining binocular vision; or - the first value of the spherical refraction for each eye of the subject is determined by testing each eye separately from the other while maintaining binocular vision, and the second value of the spherical refraction for each eye of the subject is determined by testing both eyes simultaneously in binocular vision, or - the first and second values ​​of spherical refraction for each eye of the subject are determined by testing each eye separately from the other while maintaining binocular vision; - the first and second values ​​of spherical refraction and the preliminary value of cylindrical refraction for each eye of the subject are determined by testing each eye separately from the other while maintaining binocular vision, and the first value of spherical refraction, the preliminary values ​​of cylinder and axis, and the second value of spherical refraction are obtained by alternating measurements of the first eye and the second eye of the subject, - in step d), each eye is examined separately from the other while maintaining binocular vision in order to determine the preliminary value of the cylindrical power of each eye, said preliminary values ​​of the spherical and cylindrical powers of the eye include a spherical power Se and a cylindrical power Ce having an orientation represented by an angle Ae, or an equivalent spherical power Me equal to the spherical power Se plus half the cylindrical power Ce, and the refractive powers J0e, J45e of two Jackson cross cylinder lenses representing the cylindrical power characteristics of the eye, - between steps d) and e), a step of adjusting the binocular balance of the subject's eyes is carried out to obtain adjustment values ​​of the spherical and cylindrical powers of the eye in near or intermediate vision conditions, and in step e) the binocular vision perception of the subject is ascertained by providing the eye with a vision correction power of each of the first and second optical refractive elements equal to the adjustment values ​​of the spherical and cylindrical powers plus a predetermined spherical power, - in step d), a first test image and a second test image are provided to the first and second eyes of the subject, the first and second test images comprising images of a practical activity performed in near vision having a plurality of stereoscopically displayed peripheral image components, which are perceived in three dimensions by the subject, - in each step, each eye is examined separately from the other while maintaining binocular vision; - providing a test image of the subject's eye having a target, the test image including an image of a practical activity performed in near vision having a plurality of peripheral image components and a test target displayed in a central portion of the test image; - a similar image of a practical activity performed in near vision having a plurality of peripheral image components and no test target displayed in the center or including the same test target as that displayed on the subject eye test image, said test target of the non-subject eye test image being displayed with a lower contrast than the contrast of the test target of the subject eye test image, the non-subject eye test image being presented to the other eye, and the peripheral image components of the two test images being displayed stereoscopically, - the non-patient test image, or at least a test target of the non-patient test image, is displayed with a contrast that is less than half the contrast of the patient test image, or half the contrast of the test target of the patient test image; - in each step when both eyes are tested simultaneously, a test image having a target is presented to each eye, the test image including an image of a realistic activity performed in near or intermediate vision having a plurality of peripheral image components displayed stereoscopically, each component of the plurality of peripheral image components being displayed with a specific disparity between the images presented to the subject's both eyes, this disparity being different from the disparities associated with other components of the plurality of peripheral image components; - in each step, when both eyes are tested simultaneously in binocular vision, a test image is presented to each eye, the test image including an image of a real activity performed in near vision having a plurality of peripheral image components displayed stereoscopically and a test target displayed in the center of the test image; - each component of the plurality of peripheral image components is displayed with a particular disparity between images presented to both eyes of the subject, the disparity being different from the disparities associated with other components of the plurality of peripheral image components; - before carrying out steps a) to g), a test is carried out to determine the need to correct astigmatism of the eye, in which the refractive characteristics of the eye in a distance vision condition are determined and which comprises measuring the visual acuity of the eye using test images with different contrasts, - during steps a) to f), the first optical axis and the second optical axis of the refractive optical element are tilted downwards.

[0013] The present invention also relates to a method for determining a complete set of values ​​of the refractive properties of a subject's eye in distance viewing conditions as well as near and / or intermediate viewing conditions, comprising determining exact values ​​of the refractive properties of the subject's eye in distance viewing conditions and determining exact values ​​of the refractive properties of the subject's eye in near and / or intermediate viewing conditions as described above.

[0014] Advantageously, said determination of the exact values ​​of the refractive properties of the subject's eye in far vision conditions comprises the following steps: A) adjusting the relative positions of the subject and the refraction testing unit such that, in a far-viewing condition, the pupil of the subject's eye is aligned with the first optical axis and the second optical axis; B) determining a vertex distance between the first or second optical refractive element and the first or second eye of the subject in a distance viewing condition; C) determining a value of a parameter representative of an accommodation characteristic of the subject's eye in a far vision condition or modifying said accommodation of the subject's eye; D) determining preliminary values ​​of the refractive properties of the subject's eyes in a distance viewing condition, including at least a preliminary value of the spherical power of each eye and a preliminary value of the cylindrical power of each eye; E) checking the subject's binocular vision perception by adding a predetermined additional spherical power to the vision correction provided to the eye; F) farsightedness determining the subject's final visual acuity under the condition; G) determining accurate values ​​of the refractive properties of the subject's eye in far vision based on the results of the previous step; Including, The above steps D ) comprises the steps of: - measuring a first preliminary value of the spherical refraction of each eye of the subject; - measuring said preliminary value of cylindrical refraction for each eye; - measuring a second preliminary value of the spherical refraction of each eye of the subject, the preliminary value of the spherical refraction of each eye of the subject being determined based on the second preliminary value; are carried out in this order, The refractive characteristics of the eye in distance and near viewing conditions are determined within 24 hours.

[0015] Detailed explanation of the example The following description, referring to the accompanying drawings, will make clear what constitutes the present invention and how it can be achieved. The present invention is not limited to the embodiments shown in the drawings. Thus, when features mentioned in the claims are followed by reference signs, it will be understood that such signs are included only for the purpose of improving the comprehension of the claims and do not limit the scope of the claims. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a block schematic diagram of a method according to the present invention; [Diagram 2] FIG. 2 is a schematic diagram of an optometric device used to perform the method according to the present invention. [Diagram 3] FIG. 3 is a schematic diagram of the refraction testing unit of the optometric device of FIG. 2 , along with two side photographs of the subject used to determine vertex distance. [Figure 4] FIG. 2 is a schematic diagram of an image taken by a camera to check the centering of the eye and the refraction testing unit. [Diagram 5] 3 shows an example of a first test image and a second test image displayed by the optometric device of FIG. 2 while measuring the spherical refractive power values ​​of both eyes of a subject during the implementation of the method of FIG. 1; [Figure 6] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 while measuring the spherical refractive power value of one eye of a subject during the implementation of the method of FIG. 1; [Figure 7] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 while measuring the spherical refractive power value of the subject's fellow eye during the implementation of the method of FIG. 1; [Figure 8] FIG. 8 is a schematic diagram of the image seen by a subject while the image of FIG. 5, FIG. 6, or FIG. 7 is displayed. [Figure 9] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 while measuring the value of the cylindrical refractive power of one eye of a subject during the implementation of the method of FIG. 1; [Figure 10]3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 while measuring the spherical refractive power value of the subject's fellow eye during the implementation of the method of FIG. 1; [Figure 11] 3 shows an example of a first test image and a second test image displayed by the optometric device of FIG. 2 while checking the binocular balance of both eyes of a subject during the implementation of the method of FIG. 1; [Figure 12] 1 shows an example of a first test image and a second test image displayed by the optometric device of FIG. 2 while checking binocular vision perception of one of the subject's eyes during performance of the method of FIG. 1; [Figure 13] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 during the determination of the visual acuity of one eye of a subject during the implementation of the method of FIG. 1; [Figure 14] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 during the determination of the visual acuity of the subject's fellow eye during the implementation of the method of FIG. 1; [Figure 15] 3 shows an example of a first test image and a second test image displayed by the optometric device of FIG. 2 during the determination of the visual acuity of a subject's both eyes during the implementation of the method of FIG. 1; [Figure 16] 3 shows an example of a first test image and a second test image displayed by the optometric device of FIG. 2 during the determination of the spherical power of both eyes of a subject during the implementation of the method of FIG. 1; [Figure 17] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 during the determination of the spherical power of one eye of a subject during the implementation of the method of FIG. 1; [Figure 18] 3 shows examples of a first test image and a second test image displayed by the optometric device of FIG. 2 during determination of the spherical power of a subject's fellow eye during performance of the method of FIG. 1; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] FIG. 1 shows a block diagram of a method for determining a complete set of values ​​of the refractive properties of a subject's eye in distance and near and / or intermediate viewing conditions according to the present invention.

[0018] The method includes, in accordance with the present invention, determining accurate values ​​of the refractive characteristics of the subject's eye in a distance viewing condition (block 101 in FIG. 1 ) and determining accurate values ​​of the refractive characteristics of the subject's eye in a near and / or intermediate viewing condition (block 103 in FIG. 1 ).

[0019] Prior to carrying out the method for determining the refractive properties of the subject's eye in near and / or intermediate viewing conditions, it is preferred that the refractive properties of the eye in a distance viewing condition be determined, which may be done by a method similar to that used for near or intermediate vision as described below, or by determining the refractive properties of an optical device currently worn by the subject and adapted for the subject's distance vision.

[0020] Furthermore, in a preferred embodiment, prior to performing the method for determining the refractive characteristics of the subject's eye in near and / or intermediate viewing conditions, a test is performed to determine the need for precise correction of the eye's astigmatism (block 102 in FIG. 1 ), which includes measuring the eye's visual acuity using test images with different contrasts.

[0021] Determining the refractive characteristics of the eye in near or intermediate conditions is particularly useful when precise correction of ocular astigmatism is required.

[0022] The method according to the invention can be carried out by means of an optometric device 1. The main elements of the optometric device 1 are shown in a schematic perspective view in FIG.

[0023] The eye trial device 1 is a binocular device, enabling the determination of the refractive characteristics of each eye of a subject based on binocular measurements performed in an unobstructed state while the subject has both eyes E1, E2 open.

[0024] More precisely, during said binocular measurement, a test image is presented to each eye E1, E2 of the subject. The test images presented to the two eyes are configured such that fusion of the two test images by the brain of the subject can occur. Preferably, the two test images are stereoscopic images providing the subject with an at least partially three-dimensional representation IF, an example of which is shown in FIG. 8.

[0025] To enable three-dimensional perception of the two test images by the subject, each test image is configured to be precisely aligned with the subject's corresponding eye.

[0026] The ophthalmic trial device 1 used in the method according to the present invention includes a binocular refraction examination unit 10 having a first optical refractive element 11 adapted to provide different vision correction powers along a first optical axis OA1 and a second optical refractive element 12 adapted to provide different vision correction powers along a second optical axis OA2 (Figures 2 and 3).

[0027] The first optical refractive element 11 is configured to provide a first corrective power to a first eye of a subject, and the second optical refractive element 12 is configured to provide a second corrective power to a second eye.

[0028] By corrective power is meant a refractive power that allows for the correction of the refractive error of the subject's eye, such as sphere, cylinder and / or axis, prismatic power, etc.

[0029] The ophthalmic examination device 1 also includes a display system 20 for providing a first examination image and a second examination image, the first examination image being transmitted along a first optical path to a first optical refractive element 11 and thus to a first eye of the subject, and the second examination image being transmitted along a second optical path to a second optical refractive element 12 and thus to a second eye of the subject (Figure 2).

[0030] Thus, the image display system 20 is configured to provide a first test image I11;I21;I31;I41;I51;I61;I71;I81;I91;I101 to a first eye of the subject S, and simultaneously configured to provide a second test image I12, I22;I32;I42;I52;I62;I72;I82;I92;I102 to a second eye of the subject S, the second test image being different from the first test image.

[0031] A first test image I11;I21;I31;I41;I51;I61;I71;I81;I91;I101;I111;I121;I131 is viewed by a first eye of the subject S through a first optical refractive element 11, while a second test image I12, I22;I32;I42;I52;I62;I72;I82;I92;I102;I112;I122;I132 is viewed by a second eye of the subject S through a second optical refractive element 12.

[0032] Each of the first and second refractive optical elements 11, 12 includes a lens, a mirror, or a set of such optical components having adjustable refractive power characteristics.

[0033] In the example shown in the attached figures and described below, each of the first 11 and second 12 optical refractive elements comprises a lens with variable power. Here, the lens with variable power comprises a deformable liquid lens with an adjustable shape. The aforementioned optical axes OA1, OA2 thus correspond to the optical axes of the corresponding lenses (FIG. 3).

[0034] Alternatively or additionally, the optical refractive element may comprise a set of non-deformable lenses with different refractive powers and a mechanical system that allows some of these lenses to be selected and put together to form a lens set through which the subject can see. In this last case, to adjust the refractive power of the lens set, one or some of the lenses of the lens set are exchanged for other lenses stored in the refraction test unit. The aforementioned optical axis therefore corresponds to the optical axis of the lens placed in front of the subject's eye.

[0035] In particular, each refractive optical element 11, 12 may include a lens with a variable spherical power and an optical component with a variable cylindrical power and a variable cylinder axis.

[0036] 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, for example at a distance comprised between 1 and 5 centimetres from the eye.

[0037] Each eye of the subject can view the first test image or the second test image displayed by the display system 20 through a lens of the optical refractive element 11, 12, or through a lens set, or in an alternative implementation, by reflection on a mirror of the optical refractive element.

[0038] In the following, an ophthalmic device is described in which each refractive optical element 11, 12 comprises an optical set having a lens 11A, 12A with a variable spherical power and an optical component with a variable cylindrical power and a variable cylindrical axis.

[0039] The optical set has an overall spherical power Sph, which corresponds to a spherical power expressed in diopters. The cylindrical component of its power is that of an equivalent cylindrical lens having a cylindrical power Cyl (e.g. expressed in diopters) and with an orientation of the cylinder represented by an angle A. Each of the first and second refractive corrections provided by the corresponding optical refractive elements 11, 12 can be characterized by the values ​​of these three power parameters Sph, Cyl and A.

[0040] This refractive correction can equally be characterized by the values ​​of any other set of parameters representing the above-mentioned refractive power characteristics of the optical set of optical refractive elements 11, 12, such as the triplet {M, J0, J45}, where the equivalent spherical power M is equal to the spherical power S plus half the cylindrical power C (M=S+C / 2), and J0 and J45 are the refractive powers of two Jackson cross cylinder lenses representing the cylindrical refractive characteristics of the lens or lens set of optical refractive elements 11, 12.

[0041] The refractive optical elements 11, 12 are mounted on a common support 13 which extends between and above the refractive optical elements along a horizontal longitudinal axis H (Figure 3).

[0042] This support 13 is connected to an overall support structure (not shown or only partially shown) that rests on a table or on the ground.

[0043] Each of the refractive optical elements 11, 12 is mounted on a support 13 for rotational movement about an axis V1, V2 perpendicular to said longitudinal axis H. The mean planes MP of the first 11 and second 12 optical refractive elements pass through these axes V1, V2 (FIG. 3). This mobility of the refractive optical elements allows adjustment of the alignment of the optical axes OA1, OA2 with the subject's eyes, taking into account the convergence of the eyes in near vision conditions.

[0044] The display system 20 is adapted to provide the first and second test images (examples of which are provided below) with detail of less than 1 arc minute over a horizontal field of view of at least 8° in near viewing conditions.

[0045] The distance between the image displayed for each eye and the refraction test unit may be fixed or variable. A change in the distance between the test image displayed by the display system and the optical refractive element may be obtained by varying the distance between the entire display system and the refraction test unit or by using movable optical components, such as mirrors, inside the display system 20.

[0046] The test image may be positioned at the near vision distance (eg, 40 centimeters) or intermediate vision distance (eg, 60 cm) of the subject's eyes.

[0047] The binocular refraction testing unit 10 is advantageously movable between at least two testing configurations, namely a horizontal vision testing configuration in which the first and second optical refractive elements are arranged in a first position in which the first and second optical axes extend horizontally, and an inclined vision testing configuration in which the first and second optical refractive elements are inclined compared to the first position, such that the first and second optical axes are inclined downwards.

[0048] Preferably, said binocular refraction testing unit moves rotationally as a whole about a horizontal axis of rotation parallel to the mean plane of the first and second refractive optical elements.

[0049] Consequently, during determination of the refractive properties of the subject's eye in near / intermediate vision, the optical axes OA1, OA2 of said optical refractive elements 11, 12 are preferably tilted downwards so that the subject is placed in an ergonomic near vision position.

[0050] Here, as shown in FIG. 2, the display system 20 is housed in a box mounted on a rail. Said rail is attached to a common support 13 for the optically refractive elements 11, 12. The rail extends generally perpendicular to the mean plane of said optically refractive elements 11, 12. The display system 20 can therefore be translated along the rail in order to vary the distance to the subject's eyes. The display system 20 may also be swiveled generally together with the refraction testing unit 10. This rail can be used to test the quality of the near and / or intermediate correction. The ability to move the display system 20 allows the range of accommodation amplitude and the sharpness of the target or object to be tested.

[0051] The image display system 20 is not the subject of the present invention and will not be described in full detail. Any image display system 20 capable of providing inspection images in stereoscopic view may be used.

[0052] In particular, the display system may be held in the subject's hand.

[0053] The display system may also be placed on a table, for example in an inclined position.

[0054] In particular, the display system 20 used in the method according to the invention may include one or two screens for displaying the inspection images.

[0055] Examples of test images displayed by the screen are shown in Figures 5-7 and 9-15. One of the two test images (the image on the right in each figure) is transmitted to the corresponding eye with no reflection or with an even number of reflections. The other test image (the image on the left in the figure) is transmitted to the eye with an odd number of reflections. The screen displays a mirror image of the other test image so that the other test image is presented to the eye in the appropriate orientation. Figures 16-18 show examples of test images displayed by the screen in which two test images are transmitted to the corresponding eye with both odd and even number of reflections.

[0056] For example, a liquid crystal display screen may be capable of displaying a first test image using a first polarization and simultaneously displaying a second test image using a second polarization. Also, two screens may be used that display the first test image using a first polarization and the second test image using a second polarization. The first and second polarizations are orthogonal to each other. For example, the first and second polarizations are both linear and perpendicular to each other. Or, similarly, the first polarization is left-handed circular polarization and the second polarization is right-handed circular polarization.

[0057] The entire extent of the screen or of the two screens may be visible through each of the first 11 and second 12 optical refractive elements.

[0058] However, the first optically refractive element 11 includes a first polarizing filter that filters the light coming from the image display system 20. The first polarizing filter can filter out the second polarized light and pass the first polarized light to reach the first eye of the subject. Thus, through the first optically refractive element 11, the first eye of the subject can see the first test image but not the second test image.

[0059] Similarly, the second optically refractive element 12 includes a second polarizing filter that filters the light coming from the image display system 20. The second polarizing filter can filter out the first polarized light and pass the second polarized light to reach the second eye of the subject.

[0060] The image display system may use any other separation technique, such as <<active>> separation, where each image study is displayed alternately at a high frequency while a synchronized electronic shutter or polarizer blocks the eye to which the image should not be sent. The separation system may also use separation with color filters on both the display and the eye, where each side / eye has a different color filter (e.g. a red filter and a green filter) that blocks the other.

[0061] The optical device used to implement the method according to the invention is controlled by a computer programmed to implement the corresponding steps of the method, said computer receiving the results of the measurements performed and input of the subjects' answers to the subjective visual tests carried out during the method, as described below.

[0062] In particular, the subject may be provided with a joystick, mouse, keypad, or other input device to provide responses to the subjective test.

[0063] According to the invention, a method 103 for determining the refractive properties of an eye of a subject in near and / or intermediate vision comprises at least the following steps: a) adjusting the relative positions of the subject and the refraction testing unit such that the pupil of the subject's eye is aligned with the first optical axis and the second optical axis in near and / or intermediate vision conditions; b) determining a vertex distance between the first or second optical refractive element and the first or second eye of a subject in near and / or intermediate viewing conditions; c) determining 300 values ​​of parameters representative of the accommodation properties of the subject's eye in near and / or intermediate viewing conditions; d) determining 400 preliminary values ​​of the refractive properties of the subject's eyes in near and / or intermediate viewing conditions, including at least a preliminary value of spherical refraction for each eye in near and / or intermediate viewing conditions and a preliminary value of cylindrical refraction for each eye in near and / or intermediate viewing conditions; e) confirming the subject's binocular vision perception by adding a predetermined additional spherical power to the vision correction provided to the eye; f) determining the subject's final visual acuity in near and / or intermediate vision conditions; g) determining 700 the exact values ​​of the refractive properties of the subject's eye in near and / or intermediate vision based on the results of the previous steps; Including, In said step d), the following steps are carried out: - measuring 410 a first value of spherical refraction for each eye of the subject; - measuring said preliminary value of cylinder power for each eye; - measuring 430 a second value of the spherical refraction of each eye of the subject, the preliminary value of the spherical refraction of each eye of the subject being determined based on the second value; are performed in this order.

[0064] Preferably, during steps a) to e), the first optical axis and the second optical axis of the refractive optical element are tilted downwards.

[0065] Thus, an ergonomic near or intermediate viewing posture is provided to the subject, making the measurements performed more accurate.

[0066] The method is implemented, for example, by a control unit including a computer having at least a processor and a memory.

[0067] Process a) In step a), the relative positions of the subject and the refraction testing unit 10 are adjusted so that the pupil of the subject's eye is aligned with the first optical axis OA1 and the second optical axis OA2 of the optical refractive elements 11, 12 in near and / or intermediate vision conditions.

[0068] To achieve this, the subject's head position and orientation may be modified.

[0069] The position and orientation of the first optical axis OA1 and the second optical axis OA2 of the refraction inspection unit 10 may also be modified.

[0070] In particular, the refractive optical elements 11, 12 can be moved in their mean plane along the longitudinal axis H of the support 13. This makes it possible to adjust the distance between the two refractive optical elements 11, 12 depending on the interpupillary distance of the subject or the monocular pupillary distance of the subject.

[0071] The optical refractive elements 11, 12 may be pivoted about their vertical axes V1, V2 to allow adjustment of the alignment of the optical axes OA1, OA2 with the subject's eyes taking into account ocular convergence in near viewing conditions.

[0072] The subject's head may be guided into the appropriate position by a head support 60 (FIG. 2) on which the subject can rest their chin and / or forehead.

[0073] An alignment verification device including a camera or eye-tracking device aimed at the subject's eyes may be used to confirm alignment and to further guide the movement of the optical refractive element and the subject's head.

[0074] In particular, the alignment verification device may include a retractable camera adapted to be positioned in front of the subject, for example in front of the center of one of the screens, to verify the alignment, and to be removed when the eye is to be tested. It is highly preferred that the camera, in operation, has its optical axis close to the center of the test image, to avoid parallax errors in checking eye alignment. When not in use, the camera is retracted out of the optical path of the light emitted by the screen.

[0075] The retractable camera is therefore movable between two positions: a first position in which it is positioned in front of the subject's head with its optical axis perpendicular to the mean plane of the optical refractive elements 11, 12 of the refraction testing unit 10, and a second position in which it is out of the optical path of the light in the eye examination device 1.

[0076] Alternatively, a fixed camera located outside the optical path of the display system may be used.

[0077] The eye alignment verification can be performed by comparing the position of the center of the eye pupil with the center of the refraction test unit optics or the optical axis of each of the optical refractive elements 11, 12. The optical axis or center of the optics and the position of the eye pupil can be determined from image processing, for example by detecting the rounded edges of the optics and the circular shape of the pupil. Alternatively, instead of detecting the rounded edges of the refraction test unit optics, a known pattern can be used, for example identifying a small cross printed in the center of the lens of the optical refractive test element.

[0078] The camera is preferably a near infrared camera to easily capture eye features such as pupil position.

[0079] An image captured by such a camera is shown in Figure 4. The edges of the image of the pupil of the subject S's eye and the images Im11A, Im12A of the lenses of the optical refractive elements Im11, Im12 can be identified and their positions compared to check the alignment of the centre of the pupil with the centre of the lenses 11A, 12A.

[0080] The alignment verification device may also include an eye-tracking device or sensor. The eye-tracking device may be fixed on the refraction test unit 10 near the eye, for example, close to the lenses 11A, 12A. The sensor may be integrated into one of the screens of the display system 20 or may be added to the display system 20. Data generated by the eye-tracking device or sensor may provide an indication from which the eye orientation and gaze direction may be estimated. Data from the sensor may also be used to determine the distance between the eye and the corresponding test image.

[0081] The alignment verification device may also include a sensor attached to the refraction inspection unit for measuring the tilt of the refraction inspection unit.

[0082] Alternatively, an eye-tracking device may be used to measure the gaze direction of the subject's eyes and compare it with the directions of the optical axes OA1, OA2 to ensure that they are parallel and preferably overlapping.

[0083] Finally, the camera may also be used to determine the near vision distance. Elements of the refraction inspection unit with known size (prints, edges of lenses of optical refractive elements, etc.) can be identified on the images captured by the camera. The distance from the camera to the refraction inspection unit 10 can then be derived from the pixel size of the images of these elements.

[0084] When using eye tracking device, eye behavior can be determined. Dynamic tracking can be synchronized with the screen. When performing the steps of the method according to the present invention and when determining the refractive properties of the subject's eye, eye tracking device can determine and take into account the subject's head position, eye position, gaze direction, and eye-to-target distances used in different visual activities (reading, using smartphone, using computer, reading music).

[0085] In a variant, the so-called Harmon distance of the subject and / or the natural posture of the subject may be determined and taken into account when determining the refractive properties of the subject's eye. The Harmon distance is the subject's appropriate working distance for near activities. Any device may be used that allows the measurement of the subject's working distance in near and / or intermediate vision conditions.

[0086] This step a) ensures that the eye is accurately aligned with the test image displayed by the display system 20. Thus, the stereoscopic peripheral components of said test image are visible to the eye in three dimensions. Subject comfort and the accuracy of the measured eye refractive value are improved.

[0087] Step a) is preferably performed before carrying out other steps of the method according to the invention. Other steps of the method according to the invention, which require the measurement of a visual property or characteristic of a subject, are performed when the relative position of the subject and the refraction testing unit is adjusted according to this step a). In particular, steps b) to f) are performed when the relative position of the subject and the refraction testing unit is adjusted according to this step a).

[0088] Step b) In step b) at least a profile image of a subject S positioned in front of the refraction testing unit is acquired.

[0089] Preferably, two profile images PIR, PIL of the subject are acquired, each taken from a different side of the subject.

[0090] These profile images are taken, for example, by an infrared camera housed inside the refraction testing unit 10 and pointed towards the eye.

[0091] An example of such profile images PIR, PIL is shown in FIG.

[0092] Each profile image PIR, PIL shows an image of one of the subject's eyes and the surface of a lens placed nearby.

[0093] From this profile image, the vertex distance between each of the subject's eyes and the corresponding optical refractive test element is then estimated.

[0094] This vertex distance may be estimated from the distance measured between the vertex of the eye image and the vertex of the corresponding lens surface image in said profile images PIR, PIL.

[0095] If a single profile image is taken, the vertex distance for each eye is determined to be the same based on this single profile image.

[0096] If two profile images are taken, the vertex distance is determined for each eye.

[0097] For far vision, the vertex distance is, for example, comprised between 11 and 13 millimeters, for near vision, the vertex distance is, for example, comprised between 17 and 19 millimeters.

[0098] The vertex distance depends on the morphology of the subject's head and the relative position of the head and the optometric device. The vertex distance also depends on the position (horizontal or inclined) of the optical axes OA1, OA2 of the optometric device.

[0099] Once the vertex distance between each eye under test and the corresponding optical refractive element 11, 12 has been determined, the vertex distance can be taken into account in step g) to determine said accurate values ​​of the refractive properties of the subject's eye in near and / or intermediate vision.

[0100] This vertex distance may also be compared with the distance between the eye and the lens of the spectacles prepared for the subject. The value of the corrective power of the ophthalmic lens of the spectacles may be determined by taking into account said vertex distance value measured in step b) and the distance between the eye and the lens of the spectacles prepared for the subject, in particular the difference therebetween.

[0101] Alternatively, the vertex distance is not measured but is predetermined by positioning the subject's head so that the vertex distance is equal to this predetermined value, for example comprised between 10 and 40 millimeters, for example equal to 25 millimeters.

[0102] The vertex distance is preferably measured for each eye while the subject and the refraction testing unit are in the adjusted relative positions determined in step a).

[0103] In the method according to the present disclosure, the vertex distance remains constant for all subsequent steps performed using the refraction inspection unit 10 .

[0104] Optional preliminary vision test process Optionally, before step d), or preferably between steps b) and c), a preliminary vision test 250 (FIG. 1) of the subject's eyes is performed.

[0105] This step is performed in near or intermediate viewing conditions that correspond to the visual conditions of the test currently being performed.

[0106] Initial values ​​of refractive power, in particular initial sphere and / or cylinder power and axis, are applied to the optical set of each optical refractive element 11, 12, here the variable power lenses 11A, 12A and the optical components having variable cylinder power and variable cylinder axis.

[0107] These initial values ​​of refractive power may be determined based on the refractive properties of the subject's existing optical equipment, for example the refractive power of the ophthalmic lenses of the subject's existing spectacles.

[0108] These may be determined based on previous values ​​of the refraction of the eye determined during a previous examination of the subject, which may have been performed at a previous date, for example when testing the subject's visual acuity in order to prescribe the subject an existing or previous optical device.

[0109] These initial values ​​of refractive power may also be determined based on the refractive characteristics of the subject's eye measured in distance viewing conditions immediately prior to carrying out the method of the invention, or, preferably, on the same day, within the previous 24 hours.

[0110] The preliminary vision test 250 is performed by testing each eye separately from the other and / or by testing both eyes simultaneously.

[0111] Each test eye is presented with a test image that includes a visual target. If only one of the two eyes is being tested, the fellow eye is presented with an image without the visual target.

[0112] The visual target may include, for example, a row of indicia such as letters of different sizes, similar to target T5 in the test image of Figures 13-15, which has only one letter per row.

[0113] The question asked of the subject might be, "I'm going to present you with a string of letters, which is the smallest line of letters you can read without straining, squinting, or moving closer? You can check your visual acuity by telling me the line number."

[0114] Determination of this preliminary visual acuity gives information on the necessity of carrying out further steps of the method and also on the difference between the initial value of the refractive power used and the refractive properties of the subject's eye in near vision.

[0115] Preferably, the preliminary vision test is performed while the subject and the refraction test unit are in the adjusted relative positions determined in step a), using the vertex distance of each eye determined in step b).

[0116] Process c) In the following step c), values ​​of parameters representative of the accommodation properties of the subject's eye in near and / or intermediate vision conditions are determined, which step c) is carried out for each eye in the relative position of the subject and the refraction testing unit determined in step a), while maintaining the vertex distance determined in step b).

[0117] Preferably, said parameters representative of the accommodation properties of the subject's eyes in near and / or intermediate viewing conditions are binocular parameters.

[0118] A binocular accommodation test is performed by presenting an identical target to each eye of the subject, the target being located at a near or intermediate viewing optical distance from the eye of the subject, modifying the spherical power of the lens of each of the first and second optical refractive elements, and determining the minimum spherical power for the subject to accommodate to the target, and determining the value of the parameter representative of the accommodation properties of the eye. The identical target is presented to both eyes simultaneously.

[0119] Each of said identical targets comprises, for example, several rows of optotypes. The initial value of the spherical power of the optical refractive elements 11, 12 is determined, for example, on the basis of the refractive characteristics of the subject's existing optical equipment, for example the refractive power of the ophthalmic lenses of the subject's existing spectacles, on the basis of previous values ​​of the refraction of the eye determined during a previous examination of the subject, or on the refractive characteristics of the subject's eye measured in distance viewing conditions before carrying out the steps of the method. No cylindrical power is used.

[0120] The spherical power of the optical refractive elements 11, 12 is successively increased until the subject demonstrates that he or she can distinguish the target.

[0121] The subject's range of accommodation can then be determined, the range of accommodation being relative to the distance between the farthest point that can be clearly seen when the eye is relaxed, i.e., not accommodating, and the nearest point that can be clearly seen when the eye is accommodating.

[0122] The accommodation range can also be expressed as the spherical refraction range of the subject, which quantifies the range between the spherical refraction of the subject's eye when accommodating to the nearest point that can be clearly seen when the eye is accommodated, and the spherical refraction of the subject's eye when accommodating to the farthest point that can be clearly seen when the eye is relaxed.

[0123] In another embodiment, the parameter describing accommodation may refer to the spherical power of at least one of the eyes in a particular state of accommodation, for example at maximum accommodation in near vision or relaxed in distance vision.

[0124] According to this embodiment, vision tests are performed using the refraction test unit 10 to determine the spherical power of each eye in uncorrected distance vision. Preferably, these vision tests are similar to those described above. These vision tests provide a set of spherical power values ​​for the optical refractive elements 11, 12.

[0125] Based on the values ​​of the parameters describing the accommodation of the subject's eyes, the spherical power of each eye in the relaxed state can be determined, which is stored in the computer memory and used as a starting point for step d) of the method according to the present disclosure.

[0126] Step d) After the steps already described, in step d) preliminary values ​​of the refractive properties of the subject's eye in near and / or intermediate vision conditions are determined. For example, near and / or intermediate vision conditions refer to a visual acuity test performed at a constant distance from the subject's eye. The constant distance is comprised in the distance range of 20-60 centimeters. According to a preferred embodiment, the visual acuity test is performed at a constant distance of 40 centimeters from the subject's eye. The vertex distances and relative positions determined in steps a) and b) are maintained during step d).

[0127] More precisely, in step d) at least a preliminary value of the spherical power of each eye in the near and / or intermediate viewing condition and a preliminary value of the cylindrical power of each eye in the near and / or intermediate viewing condition are determined.

[0128] In practice, step d) comprises the following steps: - d1) measuring a first value of the spherical refraction of each eye of the subject; - d2) measuring said preliminary value of cylindrical refraction for each eye; - d3) measuring a second value of the spherical refraction of each eye of the subject, taking into account a preliminary value of the cylindrical refraction, said preliminary value of the spherical refraction of each eye of the subject being determined on the basis of said second value; are performed in this order.

[0129] Preferably, for the following steps of the method according to the present disclosure, the preliminary value of the spherical refraction of the subject's eye is equal to the second value of the spherical refraction determined in step d3).

[0130] In the following paragraphs, the preliminary cylinder power values ​​refer to the astigmatism characteristics of each eye of the subject, and therefore include the cylinder and / or axis of each eye.

[0131] Steps d1) and d2) make it possible to determine the spherical and cylindrical refraction values ​​of the eye, and step d3) makes it possible to refine the spherical refraction value of the eye.

[0132] A first value of the spherical refraction is determined without any modification of the cylindrical refraction of the eye. This is done by a classical subjective test by presenting a target or object to the subject and asking him to evaluate the quality of his perception of the target or object. The subject is usually asked to compare the perception of two different targets or objects.

[0133] For example, in step d1), an initial value of the spherical power of the set of refractive optical elements 11, 12 used in step d1) corresponds to the accommodation characteristics determined in step c), after which the initial spherical power of the set of refractive optical elements 11, 12 is modified and a first value of the spherical power of the eye in near and / or intermediate viewing conditions is determined, for example by a classical subjective refraction test.

[0134] To determine a first value of the spherical power of each eye of the subject, only the value of the spherical power of the set of refractive optical elements 11, 12 is measured. In step d1), no cylindrical power is provided by the refractive optical elements 11, 12 and the cylindrical power of the eye is not determined.

[0135] Step d1) makes it possible to determine a first value of the spherical refraction of each eye of the subject.

[0136] Then, after determining this first value of the spherical power for each eye, in step d2), the astigmatism characteristics including cylinder and / or axis of each eye of the subject are determined.

[0137] Preferably, step d2) is performed while keeping the spherical equivalent of the set of optical refractive elements 11, 12 constant and equal to the spherical equivalent given by the first value of spherical refraction determined in step d1), which means that if during step d2) the cylinder and / or axis of the refractive elements 11, 12 are modified, the value of the spherical equivalent of the set of refractive elements 11, 12 is modified in order to keep the spherical equivalent constant.

[0138] The cylinder and / or axis of each eye determined in step d2) corresponds to a preliminary value of the cylindrical power.

[0139] Then, once the cylinder and / or axis of each eye has been determined, in step d3) a second value of the spherical power of each eye is determined.

[0140] In step d3), the value of the cylinder of the set of optical refractive elements 11, 12 is kept constant, equal to the preliminary value determined in step d2). Step d3) again makes it possible to refine the value of the spherical power for each eye determined in step d1), by taking into account the astigmatism characteristics of the eye.

[0141] A second value of the spherical power is then determined by subjecting the eye to said preliminary value of the cylindrical power, this second value corresponding to the preliminary value of the spherical power.

[0142] The subjective test may include comparing targets or objects displayed simultaneously on backgrounds of different colours, such as green and red, using different spherical or cylindrical powers and axes or cylindrical axes of the lenses 11A, 12A of the optical refractive elements 11, 12, or comparing the perception of objects of different sizes displayed one after the other, and / or comparing the perception of different parts of a target, and / or comparing the perception of the same target / object.

[0143] For example, step d1) may be performed by test images I11, I12, I21, I22, I31, I32 as shown diagrammatically in Fig. 5-7. Here, target T1 is a cross. The question to ask the subject may be: "Here is a cross. Does the line look dark, clear, more shading horizontally, more shading vertically, or is the vertical and horizontal shading the same?" Positive increments of spherical power are added to each test eye until the subject says that the horizontal and vertical lines look equally dark.

[0144] Alternatively, step d1) may also be performed using a red / green dichromatic test, as described for step D1) in distance vision.

[0145] Test images I111, I112, I121, I122, I131, I132 used in such red / green dichromatic testing are shown, for example, in Figures 16, 17, and 18. Figure 16 shows images used in binocular dichromatic testing of both eyes simultaneously, while Figures 17 and 18 show test images that would be shown if one eye is tested separately from the other, thereby leaving the other eye open and testing only one eye in an unoccluded state.

[0146] In these figures, the subject eye target T6 of the subject eye test images I122, I131 includes a row of targets. The central portion 51 of each test image I111, I112, I121, I122, I131, I132 includes a red half and a green half represented by different hatching patterns. Thus, the subject eye target T6 is more precisely a row of letters on a red-green background. The non-subject eye test images I121, I132 do not include targets in the red and green central portions. When both eyes are tested simultaneously (FIG. 16), both test images include a red / green central portion with the subject eye target T6.

[0147] Such a red-green R / V bicolor test involves a search for the maximum convex sphere. The objective is to find the sphere that gives the highest sharpness (target value -0.1 LogMAR). The examinee must choose whether the letters appear darker on one of the two backgrounds or whether the letters are the same shade. If possible, the test is performed on the 0 LogMAR acuity line if the examinee can read the full line of letters, or on the lower acuity line otherwise.

[0148] The question asked of the subject might be, "Please tell us whether you feel that the letters are more shading in red, more shading in green, or whether you feel that they are the same."

[0149] Preliminary Cylinder Value The preliminary cylinder value is determined by any known procedure.

[0150] The preliminary spherical and cylindrical values ​​of the eye may include a spherical power Se (e.g. expressed in diopters) and a cylindrical power Ce (e.g. expressed in diopters) having an orientation represented by an angle Ae. The preliminary spherical and cylindrical values ​​of the eye may also include the value of any other set of parameters that represent the above-mentioned refractive power characteristics of the eye, for example a triplet {Me, J0e, J45e} with an equivalent spherical power Me equal to the spherical power Se plus half the cylindrical power Ce (Me=Se+Ce / 2), where J0e and J45e are the refractive powers of two Jackson cross cylinder lenses that represent the cylindrical refractive power characteristics of the eye.

[0151] For example, the step of determining the preliminary cylinder power is performed by a cross cylinder test, which includes a test lens having a spheric-cylindrical combination of +0.25 diopters of sphere and -0.50 or -0.33 diopters of cylinder.

[0152] Whatever set of parameters is used to describe the refractive power of the eye, as mentioned above, said step d2) is performed such that the spherical equivalent of the optical set of refractive optical elements 11, 12 remains constant during the performance of this step. In other words, during step d2), the cylindrical power and the axis or refractive power J0, J45 of the optical set of refractive optical elements 11, 12 are modified to test the eye, and the spherical power Sph of the optical set may also be modified to ensure that the spherical equivalent remains constant.

[0153] In practice, if a change in the cylinder or refractive power J0, J45 of more than 0.5D is made in step d2), the value of the spherical power of the optical set of optical refractive elements 11, 12 is also modified in order to keep the spherical equivalent constant.

[0154] The final values ​​obtained in step d2) for the cylinder and axis or power J0, J45 of the optical refractive elements 11, 12 are taken into account as preliminary values ​​for the cylinder power of the eye determined in step d2).

[0155] The test images I41, I42, I51, I52 used in this step d2) contain a target T2 with a group of black dots on a green background, as shown for example in figures 9 and 10. The subjective test consists in simply inverting the test lens and comparing the two positions of the cross cylinder, and then asking in which position the subject perceives the image as sharper or more uniform.

[0156] The question asked of the subject might be: "Compare the two locations. Tell us in which of the two locations the dots appear clearer, darker, or they appear the same." It is also possible to use letters to test in which location these letters appear clearer, darker, or they appear the same in both locations.

[0157] In step d3), a second value of the spherical refraction is determined, taking into account the preliminary value of the cylindrical refraction of the eye determined in step d2). In practice, the optical set of the optical refractive elements 11, 12 of the refraction test unit 10 provides the preliminary value determined in step d2) of the cylindrical refraction, while a second spherical refraction value of the eye is determined, resulting in a more precise spherical refraction value. This step d3), like in step d1), is carried out by any classical subjective test.

[0158] Preferably, each of steps d1), d2) and d3) is performed by binocular vision of the subject. Two test images are presented to the subject's eyes, one test image to each of the subject's eyes. Both eyes are kept open and unobstructed. Thus, each eye sees a corresponding test image.

[0159] Each of these steps d1), d2) and d3) may be performed by testing both eyes simultaneously with binocular vision, or by testing each eye separately from the other while maintaining binocular vision.

[0160] As will be described in more detail below with reference to some examples, during simultaneous binocular testing of both eyes, the two test images presented to the subject's eyes both include a test target or visual target. During testing of only one of the subject's eyes, the test image provided for eye testing either includes a test target or visual target, while the other test image either has no target or visual target, or the same target or visual target is displayed with a lower contrast.

[0161] As a result, one of the following options is possible: - the first value and the second value of the spherical refraction of each eye of the subject are determined by simultaneously testing both eyes binocularly; or - the first value of the spherical refraction of each eye of the subject is determined by testing both eyes simultaneously in binocular vision, and the second value of the spherical refraction of each eye of the subject is determined by testing each eye separately from the other while maintaining binocular vision; or - the first value of the spherical refraction for each eye of the subject is determined by testing each eye separately from the other while maintaining binocular vision, and the second value of the spherical refraction for each eye of the subject is determined by testing both eyes simultaneously in binocular vision, or - said first value and said second value of the spherical refraction for each eye of the subject are determined by testing each eye separately from the other while maintaining binocular vision.

[0162] In this way, the accommodation state of each eye during the corresponding step of the method of the present invention will be close to the accommodation state of the eye during a normal visual task. Any difference in the accommodation state between the two eyes can be taken into account.

[0163] Preferably, to determine said preliminary value of the cylindrical power of each eye, each eye is examined separately from the other while maintaining binocular vision, in this way the visual state of the eye during the steps of the method of the invention is close to the visual state of the eye during the actual use of the corrective lens.

[0164] According to an advantageous embodiment, the first and second values ​​of spherical refraction and the preliminary value of cylindrical refraction of each eye of the subject are determined by testing each eye separately from the other while maintaining binocular vision, and the first value of spherical refraction, the preliminary values ​​of cylinder and axis, and the second value of spherical refraction are obtained by alternating measurements of the first and second eyes of the subject. In this way, it is easy to show the subject what is expected from him when performing a test on the first eye and then ask him to do the same with respect to the second eye. The process is then carried out in a fast and efficient manner.

[0165] According to another advantageous embodiment, the first and second values ​​of spherical refraction and the preliminary value of cylindrical refraction for each eye of the subject are determined by testing each eye separately from the other while maintaining binocular vision, and the first value of spherical refraction, the preliminary values ​​of cylindrical power and axis, and the second value of spherical refraction are obtained by performing measurements only on the first eye and then only on the second eye of the subject.

[0166] The first value of spherical power, the preliminary values ​​of cylinder and axis, and the second value of spherical power are then obtained successively for the first eye, and then successively for the second eye, so that the steps are performed in a rapid and efficient manner, since there is no need to switch from one eye to the other at each step.

[0167] As will be explained in more detail below, some subjects have binocular vision that is strongly dominated by the image perceived by one of the subject's eyes, referred to as the dominant eye, in which case, in any embodiment, it is preferred that the general approach be to start with the subject's non-dominant eye and finish with the dominant eye.

[0168] For example, when measurements of the first eye and the second eye are alternately performed in each step, it is preferable that the first eye is the non-dominant eye and the second eye is the dominant eye in each step.

[0169] When the preliminary values ​​are all determined for a first eye and then all determined for a second eye, the first eye is also preferably the non-dominant eye and the second eye is preferably the dominant eye.

[0170] Finally, a preliminary value of the spherical refraction of each eye of the subject is determined based on the second value. The second value is indeed more accurate, since it was determined with a correction of the astigmatism of the subject thanks to the preliminary value of the cylindrical refraction determined in step d2). The preliminary value of the spherical refraction is, for example, equal to the second value.

[0171] Alternatively, a preliminary value of the spherical refraction for each eye of the subject may be determined, taking into account the age of the presbyopic subject, for example, using the database available at https: / / www.em-consulte.com / em / SFO / rapport / file_100013.html.

[0172] Optional step of adjusting binocular balance Between steps d) and e) a step 450 (FIG. 1) of adjusting the binocular balance of the subject's eyes is performed to obtain an adjusted value of said refractive properties of the eyes in near or intermediate viewing conditions.

[0173] Binocular balance testing may be performed by any known procedure.

[0174] The initial values ​​of the sphere and cylinder powers and axes of the lenses of the optical refractive elements 11, 12 are here equal to the preliminary values ​​of the eye refraction determined in step d).

[0175] These preliminary values ​​are modified by adding or subtracting the spherical power of the lens to achieve binocular balance for the subject's eyes.

[0176] To achieve this binocular balance, the spherical power reserve is modified to ensure accurate recognition of the target, for example by limiting the difference in spherical power between the two eyes to 0.32 diopters, while maintaining visual acuity above a certain threshold.

[0177] Binocular balance is the difference between the equivalent sum of the right eye and the left eye.

[0178] The equivalent sum for each eye is equal to the spherical equivalent for near vision minus the spherical equivalent for distance vision of the corresponding eye.

[0179] The binocular balancing process is accomplished by simultaneously presenting specific targets T3A, T3B to both eyes, for example as shown in FIG.

[0180] Each particular target T3A, T3B comprises several rows of dots on a green background, the rows of dots appearing to darken from top to bottom in one of the test images and from bottom to top in the other test image.

[0181] The subject's vision is blurred by adding a positive spherical increment, for example 0.5 diopters, so that the subject can still see the dots or rows of dots presented for performing the test. In each eye, half of the dots or rows of dots appear darker, and when the two eyes are brought together, the intermediate row is seen.

[0182] If the two eyes are not balanced, the subject will see the dots above or below as darker, so for the eye looking at the corresponding test image with a horizontal row of dark dots above or below, positive spherical power increments are added until all rows of dots appear to be of uniform darkness.

[0183] A question asked of the subject during this test might be, "I'm going to change my glasses. Tell me when the matrix of dots is of uniform darkness."

[0184] Thereafter, the adjusted sphere value of the corresponding eye's refractive power is determined by adding the positive sphere increment to the preliminary value determined in step d).

[0185] If this step is performed, then in the following step an adjustment value of the spherical power of the eye is used, and then in the following step e) said binocular visual perception of the subject is ascertained by providing him with a vision correction power equal to said adjustment value plus a predetermined spherical power, as described below.

[0186] Otherwise, the following steps are performed based on the preliminary value determined in step d).

[0187] Process e) Step e) of the method according to the present disclosure aims to verify whether the preliminary values ​​of spherical and cylindrical powers of each eye determined in step d) are suited to the visual acuity of the subject.

[0188] In step e), the subject's binocular vision perception is confirmed by adding a predetermined spherical power to the vision correction power provided to the eye according to the result of step d). While adding the predetermined spherical power in step e), the cylindrical power determined in step d) is maintained.

[0189] In practice, the spherical power of the lens placed in front of the eye before carrying out step e) is equal either to the preliminary value of the spherical power of the eye determined in step d) or to the adjusted value of the spherical power of the eye determined in any step of binocular balancing.

[0190] A test image presented to the subject's eyes is, for example, shown in Figure 12. Both eyes are tested together by binocular vision.

[0191] The test images I71, I72 presented to the examined eyes contain here a target T4 in the form of a visual line of a visual target (FIG. 12).

[0192] The question asked of the subject might be, "Do you feel that the letters are sharper, darker, blurrier, or the same in position 1, 2?"

[0193] The binocular visual perception of the subject is tested by adding a predetermined value of spherical power to the preliminary value of the spherical power of the eye determined in step d) or to the adjusted value of the spherical power of the eye determined in any step of binocular balance, and displaying two test images having targets or visual targets.

[0194] The predetermined spherical power addition may be positive or negative. The predetermined spherical power addition may be, for example, comprised between 0.1 and 0.3 diopters or between -0.3 and -0.1 diopters, for example equal to 0.25 or -0.25 diopters. The subject is then asked to compare the vision of the target or optotype with and without the predetermined addition.

[0195] Then, by adding said predetermined additional value, the subject's visual acuity is expected to decrease, which indicates that the preliminary or adjustment value is an optimal value. If the subject's visual acuity or subjective comfort is in fact decreased by adding the predetermined additional value of the spherical power, the predetermined additional value of the spherical power is removed and the preliminary or adjustment spherical refraction value remains unchanged.

[0196] If this is not the case, the corrected spherical refraction value of the eye is determined.

[0197] The corrected spherical refraction value for each eye may be equal to the sum of a predetermined sum of the spherical powers and the preliminary value of the spherical refraction of the eye determined in step d).

[0198] Alternatively, if the optional step of binocular balancing has been performed, the corrected spherical refraction value for each eye is equal to the sum of the predetermined sum of the spherical powers and the adjustment of the spherical refraction of the eye determined in the optional step of binocular balancing. Step e) is repeated.

[0199] A predetermined addition of negative spherical power may be added. If the improvement in vision is significant, for example, if there is an improvement of more than three letters, this predetermined addition of negative spherical power is taken into account to determine the new corrected spherical refraction value.

[0200] The new corrected spherical refraction value is equal to the sum of the predetermined addition of the spherical power and the reserve, adjustment, or correction of the spherical refraction of the eye. If the subject does not perceive a significant improvement in perception, the spherical refraction value is not changed.

[0201] Process f) In step f), the subject's final visual acuity in near and / or intermediate viewing conditions is determined when the subject's eye is given a vision correction equal to the preliminary values ​​of the eye's sphere and cylinder, or equal to the adjusted values ​​of the eye's sphere and cylinder when a binocular balancing step is performed. The subject's visual acuity is then verified to be above a predefined threshold, such as 10 / 10 or better, e.g., 0.0 LogMAR visual acuity.

[0202] Visual acuity is determined binocularly with both eyes simultaneously or with each eye separately from the other.

[0203] Examples of the test images I81, I82, I91, I92, I101, and I102 used are shown in, for example, Figures 13 to 15. The test images I81, I92, I101, and I102 provided to the subject's eye include a target T in the center thereof. The target T includes rows of targets of different sizes.

[0204] If this is not the case, steps a) to e) are repeated.

[0205] In one embodiment, the subject's visual comfort and reading speed for each eye or both eyes combined is also determined.

[0206] According to this embodiment, based on the result given in step f), a vision correction is provided to the subject's eye. The reading speed can then be checked according to the method disclosed in EP 3622343. Alternatively or additionally, the visual comfort can be checked according to the method disclosed in EP 3622343. If the reading speed or visual comfort is below a predefined threshold value for reading speed or visual comfort, steps a) to f) are repeated.

[0207] Process g) In said step g), based on the result of the previous step, said precise values ​​of the refractive properties of at least one eye of the subject in near and / or intermediate vision are determined.

[0208] Preferably, in step g) precise values ​​of the refractive properties of both eyes of the subject in near and / or intermediate vision are determined.

[0209] In particular, said exact value is determined on the basis of said preliminary or adjusted value of the spherical power of the eye and said preliminary value of the cylindrical power of the eye, taking into account the vertex distance determined in step b), said exact value being equal to said correction value obtained in step f), i.e. the correction value determined in the last step e) performed if step e) is repeated after step f).

[0210] The correction value of the refractive properties of the subject's eyes determined in step e) is determined in the relative position determined in step a) using the vertex distance determined in step b), taking into account the accommodation parameters determined in step c) and used as a starting point in step d), the preliminary values ​​determined in step d) and, optionally, the adjustment values ​​determined when the step of adjusting the binocular balance of the eyes is performed, and finally, the binocular vision perception confirmed in step e) and the final vision confirmation performed in step f).

[0211] Taking the vertex distance into account in order to obtain accurate values ​​of the sphere and cylinder powers is important insofar as the distance between the eye and the corrective ophthalmic lenses of the spectacles prepared for the subject on the basis of these values ​​may differ from the vertex distance determined in step b).

[0212] The distance between the eyes and the corrective ophthalmic lenses of the spectacles prepared for the subject depends on the shape of the selected spectacle frame as well as on the morphology of the subject's head.

[0213] To determine the exact value of the corrective power of the ophthalmic lenses to be attached to the spectacles to be worn by the subject, said exact value of the refractive characteristics of the eye and said distance between the eye and the corrective ophthalmic lenses of the spectacles prepared for the subject are taken into account.

[0214] During the implementation of the method of the invention, the distance between the eye and the corrective ophthalmic lenses of the spectacles is taken into account when determining the refractive properties of the eye in near, far or intermediate vision, which is useful for the design of the lenses and, especially for aspheric and custom progressive lenses, for the accurate fitting of the lenses in the corresponding frames.

[0215] Indeed, in the particular embodiment detailed herein, the first and second test images provided by the display system 20 to the subject's first and second eyes include a plurality of peripheral image components that are displayed to appear three-dimensional.

[0216] The peripheral image components are stereoscopically positioned on the two test images such that the two test images appear three-dimensional to the subject when viewed by corresponding eyes.

[0217] The test image, or at least its peripheral portion, shows practical activities that are usually performed with near vision, such as cooking, reading, or using a computer, In this last case, the peripheral portion of the test image may include a joystick, a mouse, a keypad, or any other usual device of a computer.

[0218] The activities may be customized to the subject and designed to capture their attention, for example according to their age. Test images of games may be used for children.

[0219] As described in more detail below, each of the displayed first and second inspection images includes: a central part 51 for displaying the targets T4, T5, T6 (FIGS. 12 to 18) or any visual target T1, T1', T2, T2', T3A, T3B, or for the remaining blank space; and - a peripheral portion 52 which surrounds the central portion 51 and contributes to a well-balanced fusion process between the left and right visual pathways of the subject S, thereby providing the subject with comfortable binocular vision.

[0220] In each step, each eye is tested separately from the other while maintaining binocular vision. - subject eyes are provided with test images I21, I32, I41, I52, I81, I92, I122, I131 including images of real activities performed in near vision having a plurality of peripheral image components and subject eye targets T1, T2, T4, T5, T6 displayed in the central part of the test images (Figures 6, 7, and 9, 10, 13, 14, 17, 18); - includes similar images of practical activities performed in near vision having multiple peripheral image components; The target is not displayed in the center of the non-subject eye test image (FIGS. 13, 14, 17, and 18), or The non-subject eye targets T1' and T2' are displayed with a lower contrast than the contrast of the subject eye targets displayed on the corresponding subject eye test images (FIGS. 6, 7, 9, and 10). Any one of the test images I22, I31, I42, I51, I82, I91, I121, and I132 of the non-tested eye is provided to the fellow eye.

[0221] In each step where both eyes are tested simultaneously in binocular vision, each eye is provided with test images I11, I12, I61, I62, I71, I72, I101, I102, I111, I112 which include an image of a real activity performed in near vision having multiple peripheral image components and test targets T1, T2, T3A, T3B, T4, T5 displayed in the center of the test image (Figures 5, 11, 12, and 15, 16).

[0222] There are subjects who have binocular vision in which the image perceived by one of the subject's eyes, called the dominant eye, is strongly dominated. In other words, such subjects have a strong dominance of one visual pathway over the other in the neural process of binocular image fusion. For such subjects, if a completely blank image is presented to the subject's dominant eye during the binocular refraction procedure described above, a "suppression" phenomenon may occur due to binocular rivalry between the subject's left and right visual pathways. In this case, the image perceived by the subject is completely blank.

[0223] Such suppression of the visual target in the perceived image naturally makes it difficult or even impossible to determine the refractive error of the non-dominant eye while maintaining binocular vision. Even if the subject's ocular dominance is not strong enough to cause such suppression, it often causes the image perceived by the subject to flicker or blink. Furthermore, during such binocular refraction procedures, the blinking of the image perceived by the subject may also be caused by the subject's vision problems related to ocular convergence. These adverse effects reduce the accuracy or comfort of the binocular refraction procedure for the subject, and increase the time it takes to perform.

[0224] The peripheral portion 52 of the test image with the peripheral image components stabilizes the fusion of the two test images by the subject's brain and reduces the "suppression" phenomenon. In this way, the vision test becomes more comfortable for the subject and provides more accurate results.

[0225] Advantageously, the test images provided to the subject's eye using said optometric device 1 have different contrasts: the test eye test image provided to the test eye (with a target / optotype in the central part) has a contrast greater than 80%, preferably greater than 90%, preferably equal to 100%; the non-test eye test image provided to the fellow eye, with a blank central or non-test eye target, has the same contrast as the test eye target but lower, a contrast less than 15%, preferably less than 10%, preferably equal to 5%.

[0226] The contrast of any central portion with a target can be defined as: (Loptotype-Lbackground) / (Loptotype+Lbackground), where Loptotype is the luminance of the target and Lbackground is the luminance of the background.

[0227] Alternatively, the peripheral portion of the subject eye test image and the peripheral portion of the non-subject eye test image may have the same contrast, if the central portion of the non-subject eye test image contains the same target as the subject eye test image and has low contrast. Only the central portion of the subject eye test image and the central portion of the non-subject eye test image have different contrast. For example, the central portion of the subject eye test image has a contrast greater than 80%, preferably greater than 90%, preferably equal to 100%. The central portion of the non-subject eye test image has a contrast less than 15%, preferably less than 10%, preferably equal to 5%. Typically, the central portion of the non-subject eye test image has a contrast less than 50% of the contrast of the central portion of the subject eye test image.

[0228] Typically, the non-patient test image is displayed with a contrast that is less than half the contrast of the patient test image.

[0229] Additionally, to improve subject comfort and further reduce suppression effects, the peripheral portion 52 of each test image includes components with different binocular disparities.

[0230] Preferably, each component of the plurality of peripheral image components is displayed with a particular disparity between the test images presented to both eyes of the subject, which disparity is different from the disparity associated with other components of the plurality of peripheral image components.

[0231] In reality, the eyes are separated horizontally so that a subject's two eyes have different perspectives on any scene observed by the subject. The difference in the eyes' perspectives creates binocular disparity, which the brain uses to extract depth information from the combination of the two 2D retinal images.

[0232] Binocular disparity refers to the difference in the position of an object seen by the left and right eyes during binocular observation of an object. In practice, binocular disparity represents the distance between two corresponding points in the left and right images of a stereo pair, reflecting the difference in the image positions of an object seen by the left and right eyes resulting from the horizontal separation of the eyes.

[0233] A similar viewpoint difference is simulated in a stereoscopic 3D representation by generating two images that differ from each other by a viewpoint difference corresponding to a given disparity, and displaying each of them to one eye of the subject.

[0234] The disparity of the stereoscopic 3D representation of any component of the test image is determined based on the actual distance between the objects in real life to the subject and the subject's interpupillary distance, with disparity typically being larger for objects closer to the subject than for objects further away.

[0235] Disparity is sometimes expressed as the viewing angle through which a component is seen. Disparity can also be calculated as a number of pixels.

[0236] To determine parallax, the size of the screen, the interpupillary distance, and the distance between the subject's eyes and the screen are taken into account.

[0237] The test images shown in Figures 5-7 and 9-15 are test images displayed on a screen of a display system. In the example test images shown in Figures 5-7 and 9-15, the components in the peripheral portion of the test image are fruits, vegetables, or cookware. Each type of fruit, vegetable, or cookware is displayed with a different parallax. For example, the components in the peripheral portion of the test image have parallax of 1600'', 800'', 400'', 340'', 280'', 200'', 160'', 120'', 100'', and 80''. These parallaxes are expressed in arc minutes.

[0238] The central portion 51 of the example test images shown in Figures 5 to 7 each includes a visual target T1 for determining the spherical power of the eye.

[0239] FIG. 5 shows test images I11, I12 in step d1) or step d3) where both eyes are tested simultaneously.

[0240] 6 and 7 show test images I21, I22, I31, I32 displayed for testing a first eye (FIG. 6) separately from the other, and test images provided for testing a second eye (FIG. 7). In FIG. 6, a test image I21 having a test target T1 is provided to the first eye, and a non-test image I22 having a non-test target T1' identical to the test target T1 and having a lower contrast than the test target T1 is provided to the second eye. In FIG. 7, a test image I32 having a test target T1 is provided to the second eye, and a non-test image I31 having a non-test target T1' identical to the test target T1 and having a lower contrast than the test target T1 is provided to the first eye. The non-patient's eye test image I22 and the non-patient's eye test image I31 may be the same as the patient's eye test images I21, I32, and have a low contrast, for example, lower than half the contrast of the patient's eye test images I21, I32. Alternatively, the non-patient's eye test image I22 and the non-patient's eye test image I31 may be the same as the patient's eye test images I21, I32, and only the central portions may have a low contrast, for example, lower than half the contrast of the central portions of the patient's eye test images I21, I32, and the contrast of the peripheral portions of the two test images is the same.

[0241] The final image IF seen by the subject in all cases is shown in FIG.

[0242] In the illustrated example, the test images I21, I32 seen by the test eye have a contrast equal to 100%, and the non-test target T1' seen by the non-test eye has a contrast of 5%. The peripheral components of the test images I21, I22, I31, I32 are 3D (stereovision) for increased comfort and reduced inhibition. These peripheral components have different levels of 3D representation, in other words, different parallax, depending on the component.

[0243] Figures 9 and 10 show test images I41, I42 provided for performing step d2) for testing a first eye (Figure 9) separately from the other, and test images I51, I52 provided for performing step d2) for a second eye (Figure 10). The targets T2, T2' are a group or matrix of black dots on a green background. The targets T2, T2' are shown here in the center of the image of a kiwi, in order to attract the subject's attention. The peripheral part 52 of each test image contains here some fruits displayed with different parallax. The non-subject target T2' is identical to the subject target T2, as explained in the case of Figures 6 and 7, but with a lower contrast.

[0244] Figure 11 shows the test images I61, I62 used in the binocular balance process. A row of points for specific targets T3A, T3B is displayed in the center of the cake.

[0245] The peripheral portion 52 of each test image contains several ingredients of the cake displayed at different parallaxes.

[0246] Figure 12 shows the test images I71, I72 used in step e). The target T4 is displayed in the center of a book. The peripheral part 52 of each test image contains some fruit displayed at different parallaxes.

[0247] Similarly, the test images I81, I82, I91, I92, I101, and I102 shown in Figures 13 to 15 are used for visual acuity testing. A visual target T5 for the test eye is displayed in the central portion 51 of each of the test images I81, I92, I101, and I102. The peripheral portion 52 of each test image includes several fruits displayed with different parallaxes.

[0248] The central portion 51 of each non-tested eye I82, I91 does not now include a target.

[0249] In the method according to the invention, as mentioned above, the test image may be displayed by one or two screens of a display system, each screen may belong to a smartphone.

[0250] Finally, the method according to the invention is implemented by a control unit, which for example includes a computer having at least a processor and a memory, the computer being capable of being programmed to display the examination images at the appropriate times.

[0251] The test image sets of the first eye and the second eye may be placed in a memory of a computer, which may include a smartphone if the screen used belongs to a smartphone. The change from test image to the next test image may be triggered manually by the operator of the optometric device, for example by clicking on the screen when he wants to change images.

[0252] Alternatively, the control unit may comprise a smartphone different from the one or two smartphones used in the display system to provide the screen.

[0253] All smartphones are connected to the same Wi-Fi network and communicate via the TCP-IP protocol. They may also communicate using the NearbyAPI protocol.

[0254] A message is sent to each smartphone in the display system 20 indicating the method steps to be performed.

[0255] Each smartphone in the display system receives the message and opens a file containing a list of all the inspection images corresponding to this step, which, when opened, displays the first image in the list on the screen of the corresponding smartphone.

[0256] The operator can remain separate from the wearer and the examination.

[0257] According to the present invention, the method for determining the complete set of values ​​of the refractive properties of the subject's eye in distance and near and / or intermediate vision conditions also comprises a determination 101 of the exact values ​​of the refractive properties of the subject's eye in distance vision conditions, which is performed before the determination of the exact values ​​of the refractive properties of the subject's eye in near and / or intermediate vision conditions, as described above.

[0258] Advantageously, said determination 101 of the exact value of the refractive properties of the subject's eye in a distance viewing condition comprises steps similar to those of the method for determining the exact value of the refractive properties of the subject's eye in a near and / or intermediate viewing condition, which are performed with an eye trial device in a horizontal configuration.

[0259] The following steps are carried out: A) adjusting the relative positions of the subject and the refraction testing unit such that, in a far-viewing condition, the pupil of the subject's eye is aligned with the first optical axis and the second optical axis; B) determining a vertex distance between the first or second optical refractive element and the first or second eye of the subject in a distance viewing condition; C) determining a value of a parameter representative of an accommodation characteristic of the subject's eye in a far vision condition or modifying said accommodation of the subject's eye; D) determining preliminary values ​​of the refractive properties of the subject's eyes in a distance viewing condition, including at least a preliminary value of the spherical power of each eye and a preliminary value of the cylindrical power of each eye; E) checking the subject's binocular vision perception by adding a predetermined additional spherical power to the vision correction provided to the eye; F) farsightedness determining the subject's final visual acuity under the condition; G) determining accurate values ​​of the refractive properties of the subject's eye in far vision based on the results of the previous step; Including, The above steps D ) comprises the steps of: - D1) measuring a first preliminary value of the spherical refraction of each eye of the subject; - D2) measuring said preliminary value of cylindrical refraction for each eye; - D3) measuring a second preliminary value of the spherical refraction of each eye of the subject, the preliminary value of the spherical refraction of each eye of the subject being determined based on the second preliminary value; are performed in this order.

[0260] These steps are carried out as described above, except that they are adapted for distance vision testing. As described above in the description of the near or intermediate vision testing procedure, the preliminary spherical and cylindrical values ​​of the eye in the distance vision condition may include a spherical power Se and a cylindrical power Ce with an orientation represented by an angle Ae. The preliminary spherical and cylindrical values ​​of the eye may also include the values ​​of any other set of parameters that represent the above-mentioned refractive power characteristics of the eye, for example the triplet {Me, J0e, J45e} defined above. During step D2), the spherical equivalent remains constant.

[0261] The refractive properties of the eye in a distance viewing condition and a near viewing condition are determined within 24 hours, preferably on the same day, and preferably the refractive properties of the eye in a distance viewing condition are determined prior to determining the refractive properties of the eye in a near viewing condition.

[0262] It is particularly useful to have similar procedures for determining the refractive properties of a subject's eye in both distance and near / intermediate vision, which reduces the risk of having errors / deviations between the distance and near / intermediate vision measurements.

[0263] Performing both the distance vision test and the near / intermediate vision test within a short period of time also avoids errors / deviations between the two measurements.

[0264] Steps A) and B) are carried out as steps a) and b) of the method described for near and / or intermediate vision.

[0265] Steps B) to F) are performed when the relative positions of the subject and the refraction measuring unit are adjusted according to this step A).

[0266] In the method according to the present disclosure, the vertex distance for each eye determined in step B) is kept constant for all subsequent steps performed using the refraction testing unit 10 .

[0267] Step C) may be performed in a manner similar to step c) for near / intermediate vision or may correspond to a step of fogging the subject's vision to prevent accommodation, furthermore this step C) is performed at the relative position of the subject and the refraction test unit determined in step A) while maintaining the vertex distance determined in step B).

[0268] This atomization process is carried out as known from the prior art.

[0269] For example, the fogging process uses a test image in which a letter or line of letters is displayed as a target, which, when read by a subject, is blurred by a positive addition of spherical power.

[0270] The initial power of the lenses of the optical refractive elements 11, 12 is determined based on objective measurements of the refraction of the eye, for example performed with an autorefractometer, or based on the power of the ophthalmic lenses of the subject's existing optical device, or based on the subject's previous prescription.

[0271] Thereafter, the refractive power of the lenses of the optical refractive elements 11, 12 is modified: to obtain a fogging sphere value for a first target visual acuity, for example 0.3 LogMAR, a positive sphere is added in front of the subject's eye until the letters are no longer readable.

[0272] Step C) therefore also comprises a defogging step. Negative or less positive sphere values ​​are applied to the subject's eye until the most convex sphere giving the best sharpness is obtained. The added positive sphere values ​​are for example removed in order to obtain a second target visual acuity of for example about -0.1 LogMAR for a spherical eye without amblyopia. The subject is then asked: "Can you read the line of letters in the middle of the screen?"

[0273] Step C) makes it possible to provide the value of the spherical refraction of the eye in which the subject's eye has relaxed, accommodative vision.

[0274] The sphere value provided at the end of step C) is then used as a starting point for step D).

[0275] Step D) is preferably carried out as mentioned for near / intermediate vision.

[0276] For example, in step D1), the initial value of the spherical power of the set of optical refractive elements 11, 12 corresponds to the value of the spherical power that makes it possible to obtain the relaxed accommodated vision determined in step C). Step D1) is preferably performed as mentioned for near / intermediate vision.

[0277] In another embodiment of step D1), the search for the maximum convex sphere (i.e. the spherical refraction of the eye) is performed, for example, using a red / green dichromatic test. The aim is to find the sphere that results in the highest sharpness, with a final visual acuity target value equal to, for example, -0.1 LogMAR. The target is, for example, a row of letters on a red / green background. The subject must choose whether the letters appear darker on one of the two backgrounds or whether the shading of the letters is the same. If possible, the test is performed on the 0 LogMAR visual acuity row if the subject can read the entire row of letters, or on the lower visual acuity row otherwise. The question asked of the subject may be: "Tell me whether you feel that the shading of the letters is stronger on red, on green, or whether you feel that they are the same". This embodiment of step D1) provides a first value of the spherical refraction of each eye.

[0278] Other steps such as step D2) and step D3) as well as step E) and step F) are performed as mentioned for near / intermediate vision.

[0279] As mentioned in the description of the method used for near / intermediate vision, an optional step of preliminary vision testing and / or binocular balancing may be performed.

[0280] Optionally, before step D), or preferably between steps B) and C), a preliminary vision test of the subject's eyes is carried out.

[0281] This step is performed under distance viewing conditions that correspond to the visual conditions under which testing is currently performed.

[0282] Each of steps D1), D2) and D3) is preferably performed with binocular vision of the subject, either by presenting the test image to only one eye or by presenting the test image to both eyes.

[0283] Between steps D) and E) a step of adjusting the binocular balance of the subject's eyes is carried out in order to obtain an adjustment value of said refractive properties of the eyes in near or intermediate viewing conditions.

[0284] Binocular balance testing may be performed by any known procedure.

[0285] In one embodiment, prior to carrying out steps a) to g) of the method in near / intermediate vision as described above, the refractive characteristics of the eye in a distance viewing condition are determined and a test 102 is carried out to determine the need to correct the astigmatism of the eye, including measuring the visual acuity of the eye using test images with different contrasts.

[0286] Alternatively, the refractive characteristics of the eye in distance vision may be determined based on the subject's existing optical device or previous prescription.

[0287] Testing to screen and / or determine the need for correction of ocular astigmatism is performed by measuring binocular and / or monocular visual acuity in near vision using high and low level contrast visual acuity targets.

[0288] For example, a vision target including at least a row of targets is first presented to the subject's eyes at 100% contrast, and then in a second step, the vision target is presented to the eyes at a contrast including 5-10%.

[0289] If the subject's visual acuity deteriorates with decreasing contrast, different targets are presented to both eyes, including black lines radiating from a single point. The subject is asked whether all the lines appear the same. If the subject perceives some lines as darker than others, it is deemed particularly useful to determine the exact refractive properties of the subject's eyes in near and / or intermediate vision.

[0290] The subject's comfort with natural images may also be tested, and the subject's reading speed may also be tested.

[0291] In another example, a specific questionnaire may be used to determine a subject's needs and / or difficulties in near and / or intermediate viewing conditions. [Explanation of symbols]

[0292] 10 Refraction Test Unit 10 Binocular Refraction Test Unit 11 First optical refractive element 12 Second optical refractive element 13 Support 20 Image Display System 51 Central part 52 Periphery 60 Head support

Claims

1. 1. A method for determining accurate values ​​of the refractive properties of an eye of a subject (S) in near and / or intermediate vision conditions using an optometric device (1) having a refraction test unit (10) with a first optical refractive element (11) adapted to provide different vision correction powers to a first eye of the subject along a first optical axis (OA1) and a second optical refractive element (12) adapted to provide different vision correction powers to a second eye of the subject along a second optical axis (OA2), comprising: The following steps: a) adjusting (100) the relative positions of the subject (S) and the refraction testing unit (10) such that the pupils of the eyes of the subject (S) are aligned with the first optical axis (OA1, OA2) in near and / or intermediate vision conditions; b) determining (200) a vertex distance between the first or second optical refractive element (11, 12) and the first or second eye of the subject in near and / or intermediate viewing conditions; c) determining (300) values ​​of parameters representative of the accommodation properties of the eye of the subject in near and / or intermediate viewing conditions; d) determining (400) preliminary values ​​of the refractive properties of the eyes of the subject in near and / or intermediate viewing conditions, including at least a preliminary value of the spherical power of each eye in the near and / or intermediate viewing conditions and a preliminary value of the cylindrical power of each eye in the near and / or intermediate viewing conditions; e) verifying the subject's binocular vision perception by applying to said eye a vision correction equal to said preliminary values ​​of the corresponding sphere and cylinder powers plus a predetermined sphere power (500); f) determining (600) the subject's final visual acuity in near and / or intermediate vision conditions; g) determining (700) the exact values ​​of the refractive properties of the subject's eye in near and / or intermediate vision based on the results of the previous step; Including, In said step d), the following steps are carried out: - measuring a first value of the spherical refraction of each of said eyes of said subject; - measuring said preliminary value of cylindrical refraction for each of said eyes; - measuring a second value of the spherical refraction of each of the eyes of the subject, the preliminary value of the spherical refraction of each of the eyes of the subject being determined on the basis of the second value; are performed in this order: method.

2. The method of claim 1 , wherein step a) uses a camera aimed at the subject's eye, an eye-tracking device, or a support for the subject's head.

3. 3. The method according to claim 1 or 2, wherein in step b) at least a profile image (PIR, PIL) of the subject (S) positioned in front of the refraction testing unit (10) is acquired, and from this profile image (PIR, PIL) the distance between each eye and the corresponding optical refraction testing element (11, 12) is estimated.

4. 2. The method according to claim 1, wherein prior to step d), a preliminary vision test of the eye of the subject is carried out with initial sphere and / or cylinder power and axis of each optical refractive element (11, 12) determined based on the refractive characteristics of the subject's existing optical device or the refractive characteristics of the eye of the subject in far vision conditions.

5. 2. The method according to claim 1, wherein in step c) a binocular accommodation test is performed by presenting to each of the subject's eyes an identical target located at a near or intermediate vision optical distance from the subject's eyes, modifying the spherical power of each of the first and second optical refractive elements (11, 12), and determining the minimum spherical power of the first and second optical refractive elements (11, 12) for the subject to accommodate to the target.

6. 2. The method of claim 1, wherein each of the steps of measuring the first value of the spherical refraction of each of the subject's eyes, measuring the preliminary value of the cylindrical refraction of each of the eyes, and measuring the second value of the spherical refraction is performed by testing both of the subject's eyes simultaneously with binocular vision or by testing each of the subject's eyes separately from the other while maintaining binocular vision.

7. 2. The method of claim 1, wherein the first and second values ​​of spherical refraction and the preliminary value of cylindrical refraction of each eye of the subject are determined by testing each eye separately from the other while maintaining binocular vision, and the first value of spherical refraction, the preliminary value of cylindrical power, and the second value of spherical refraction are obtained by alternating measurements of the first eye and the second eye of the subject.

8. 2. The method of claim 1, wherein the preliminary values ​​of the spherical and cylindrical powers of the eye include a spherical power Se and a cylindrical power Ce having an orientation represented by an angle Ae, or an equivalent spherical power Me equal to the spherical power Se plus half the cylindrical power Ce, and the refractive powers J0e, J45e of two Jackson cross cylinder lenses representing the cylindrical power characteristics of the eye.

9. 2. The method of claim 1, wherein between steps d) and e), a step of adjusting the binocular balance of the subject's eyes is carried out to obtain an adjustment value of the spherical refraction and the cylindrical refraction of the eye in a near or intermediate viewing condition, and in step e), the binocular visual perception of the subject is confirmed by providing the eye with a vision correction power equal to the adjustment value of the spherical refraction and the cylindrical refraction, plus a predetermined spherical power.

10. In each step in which each of the eyes is tested separately from the other while maintaining binocular vision, - a subject's eye examination image (I21, I32, I41, I52, I71) with a target is presented to the subject's eye, the subject's eye examination image (I21, I32, I41, I52, I71) including an image of a real activity performed in near vision with a plurality of peripheral image components and test targets (T1, T2, T3A, T3B, T4) displayed in a central part (51) of the subject's eye examination image, - a non-subject test image (I22, I31, I42, I51, I72) is provided to the other eye, the non-subject test image including a similar image of a real activity performed in near vision having a plurality of peripheral image components and the same test target as that displayed on the subject test image, the test target having a lower contrast than the contrast of the test target in the subject test image, the peripheral image components of the subject test image and the peripheral image components of the non-subject test image are displayed stereoscopically; The method of claim 1.

11. At each step when both eyes are tested simultaneously, a test image having a target is presented to each eye, the test image including an image of a realistic activity performed in near or intermediate vision having multiple peripheral image components displayed stereoscopically; each component of the plurality of peripheral image components is displayed with a particular disparity between the test images presented to both eyes of the subject, the disparity being different from the disparities associated with other components of the plurality of peripheral image components; The method of claim 10.

12. 2. The method of claim 1, wherein prior to carrying out steps a) to g), the refractive characteristics of the eye in a distance viewing condition are determined and a test is carried out to determine the need to correct astigmatism of the eye, comprising measuring the visual acuity of the eye using test images having different contrasts.

13. 2. The method according to claim 1, wherein during steps a) to f), the first and second optical axes (OA1, OA2) of the optical refractive elements (11, 12) are tilted downwards.

14. 10. A method for determining a complete set of values ​​of refractive properties of a subject's eye in distance and near and / or intermediate viewing conditions, comprising determining (101) exact values ​​of the refractive properties of the subject's eye in distance viewing conditions and determining (103) exact values ​​of the refractive properties of the subject's eye in near and / or intermediate viewing conditions according to claim 1.

15. Said determination (101) of the exact values ​​of the refractive properties of the subject's eye in far vision conditions comprises the following steps: A) adjusting the relative positions of the subject and the refraction testing unit such that, in a far-viewing condition, the pupil of the eye of the subject is aligned with the first optical axis and the second optical axis; B) determining a vertex distance between the first or second optical refractive element and the first or second eye of the subject in a distance viewing condition; C) determining a value of a parameter representative of an accommodation characteristic of the eye of the subject in a distance viewing condition or modifying accommodation of the eye of the subject; D) determining preliminary values ​​of the refractive properties of the eyes of the subject in a distance viewing condition, including at least a preliminary value of the spherical power of each eye and a preliminary value of the cylindrical power of each eye; E) checking the subject's binocular vision perception by adding an additional predetermined spherical power to the preliminary value of the spherical power; F) determining the subject's final visual acuity in a hyperopic condition; G) determining accurate values ​​of the refractive properties of the subject's eye in far vision based on the results of the previous step; Including, In said step D), the following steps are carried out: - measuring a first preliminary value of the spherical refraction of each of said eyes of said subject; - measuring said preliminary value of cylindrical refraction for each of said eyes; - measuring a second preliminary value of the spherical refraction of each of the eyes of the subject, the preliminary value of the spherical refraction of each of the eyes of the subject being determined on the basis of the second preliminary value; The method of claim 14 , wherein:

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