JP2015211719A - Visual function testing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a visual function testing device capable of performing glare testing by respective targets under equivalent conditions while presenting a plurality of targets simultaneously.SOLUTION: A visual function testing device includes a target presentation part, a first light source part, and a second light source part. The target presentation part presents a target group arranged along a first direction. The first light source part irradiates first glare light toward an eye to be examined at a predetermined distance from a first target arranged on one end side of the target group along the first direction. The second light source part irradiates second glare light toward the eye to be examined at the predetermined distance from a second target arranged on the other end side of the target group along the first direction.

Description

  The present invention relates to a visual function inspection device.

  An example of a visual function test is a glare test. The glare test is an ophthalmic test for obtaining a visual function by causing a subject to respond to the appearance of a visual target in a state where glare light (glare light) is applied. The glare test is performed, for example, in order to grasp the influence of opacity of the lens and cornea on the vision.

  Devices disclosed in Patent Documents 1 to 4 are known as devices for performing a glare inspection. The apparatus disclosed in Patent Document 1 includes means for presenting a plurality of targets arranged vertically and horizontally, and means for applying glare light to respective left and right predetermined positions of these targets. The apparatus disclosed in Patent Document 2 has means for applying glare light to predetermined positions on the left and right sides of a single visual target. The apparatus disclosed in Patent Document 3 has a plurality of glare light sources arranged in a circle and means for presenting a visual target at the center position of the circle arrangement. The apparatus disclosed in Patent Document 4 projects a target with a measurement light source and a spot opening through which light from the measurement light source passes, and for a pair of glare lights provided above and below the spot opening. And a pair of glare light sources (glare lamps) arranged immediately after these openings are configured to apply glare light. Patent Document 4 also describes that a large number of glare light sources are arranged in a ring shape.

Japanese Patent Laid-Open No. 2005-87760 JP 2012-135528 A Patent No. 3129404 Japanese Patent No. 2848917

  When two or more glare lights are applied, in order to properly perform the glare inspection, it is necessary that the distances of the two or more glare light sources with respect to the target are equal. That is, it is necessary that the distances of two or more glare lights with respect to the visual target when viewed from the eye to be examined are equal. This is because if the effect of the glare light is not equivalent for each presented target, the inspection is performed under different conditions for each target.

  In the apparatus disclosed in Patent Document 1, a plurality of targets are presented simultaneously while applying two glare lights whose positions are fixed, and therefore the influence of glare light differs for each target.

  In the apparatus disclosed in Patent Document 2, since the two glare lights are applied to the left and right positions centered on a single target, the influence of the glare light is the same for each target. The mark cannot be presented at the same time. Therefore, the degree of freedom of presentation of the target is low, and the target to be presented must be frequently switched. The same applies to the device disclosed in Patent Document 4 that applies a pair of glare lights from above and below the target.

  In the devices disclosed in Patent Documents 3 and 4, a visual target is presented at the center of a plurality of glare light sources in a circular array. Therefore, as with the apparatus disclosed in Patent Document 2, the effect of glare light is the same for each target, but a plurality of targets cannot be presented at the same time. And the problem of target switching. Although it is conceivable to simultaneously present a plurality of targets at the center of the circular array, it is necessary to increase the size of the circular array, which increases the size of the apparatus.

  An object of the present invention is to provide a technique capable of simultaneously performing a glare test using each target while presenting a plurality of targets.

According to the first aspect of the present invention, the first target from the target presentation unit that presents the target group arranged along the first direction and the first target disposed on one end side of the target group. A first light source unit that emits first glare light toward a subject's eye from a position that is separated by a predetermined distance along the direction, and a second target that is arranged on the other end side of the target group. A visual function inspection device comprising: a second light source unit that emits second glare light toward the eye to be examined from a position separated by the predetermined distance along the direction.
Invention of Claim 2 is a visual function test | inspection apparatus of Claim 1, Comprising: The said optotype presenting part is the said some visual field arranged along the 2nd direction orthogonal to the said 1st direction. A mark group is presented, and each of the first light source unit and the second light source unit includes a surface light source whose longitudinal direction is the second direction.
A third aspect of the present invention is the visual function testing device according to the first aspect, wherein the visual target presenting unit is a plurality of the visual lines arranged along a second direction orthogonal to the first direction. A mark group is presented, and each of the first light source unit and the second light source unit includes a plurality of light sources arranged along the second direction.
A fourth aspect of the present invention is the visual function testing device according to the first aspect, wherein the visual target presenting unit is a plurality of the visual lines arranged along a second direction orthogonal to the first direction. Presenting a standard group, each of the first light source unit and the second light source unit includes a single light source or two or more light sources arranged along the second direction, the first light source unit and A first drive unit that moves the second light source unit in the second direction is provided.
Invention of Claim 5 is a visual function test | inspection apparatus of Claim 1 or Claim 4, Comprising: Each of the said 1st light source part and the said 2nd light source part is a single light source, or said 1st It includes two or more light sources arranged along a second direction orthogonal to one direction, and the target presentation unit is capable of changing the presentation position of the target group in the second direction. .
Invention of Claim 6 is a visual function test | inspection apparatus of any one of Claims 1-5, Comprising: Each of a said 1st light source part and a said 2nd light source part is said 1st direction. It is characterized by comprising a second drive unit for moving to the position.
A seventh aspect of the present invention is the visual function testing device according to the sixth aspect, wherein the second drive unit moves the first light source unit and the second light source unit in the opposite directions by an equal distance. It is characterized by doing.
Invention of Claim 8 is a visual function test | inspection apparatus of any one of Claims 1-7, Comprising: The said optotype presentation part is the brightness of the optotype contained in the said optotype group. And / or the brightness of the background of the target group can be changed.
The invention according to claim 9 is the visual function testing device according to any one of claims 1 to 8, wherein the first light source unit is capable of changing the brightness of the first glare light. The second light source unit is capable of changing the brightness of the second glare light.
The invention described in claim 10 is the visual function testing device according to any one of claims 1 to 9, wherein the target group is any one of a Landolt ring, a character target, and a contrast target. It is characterized by including these.

  According to the present invention, it is possible to perform a glare inspection with each target under the same condition while simultaneously presenting a plurality of targets.

It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the composition of the visual function inspection device concerning an embodiment. It is the schematic showing an example of the structure of the visual function inspection apparatus which concerns on a modification.

  An example of an embodiment of a visual function testing device according to the present invention will be described in detail with reference to the drawings.

  The visual function testing device according to the embodiment includes a configuration capable of performing at least a subjective visual function test, and may further include a configuration for performing another ophthalmic test. Other ophthalmic examinations may include measuring the characteristics of the eye to be examined and / or photographing the eye to be examined. Configurations according to embodiments may be part of any ophthalmic device including the devices listed below.

  As an apparatus for measuring the characteristic of the eye to be examined, an apparatus for measuring an eye refraction characteristic (keratometer, refractometer, etc .: see, for example, Patent Documents 2 and 4), a tonometer, a cornea characteristic (corneal thickness, There are a specular microscope for obtaining a cell distribution, a wavefront analyzer for obtaining aberration information of an eye to be examined using a Hartmann-Shack sensor, an axial length measuring device, and the like.

  On the other hand, as an apparatus for photographing an eye to be examined, an optical coherence tomography (Optical Coherence Tomography, OCT) for obtaining a cross-sectional image using an optical coherence tomography, a fundus camera for photographing a fundus, and a confocal optical system are used. There is a scanning laser ophthalmoscope (SLO) that obtains an image of the fundus oculi by laser scanning, a slit lamp that obtains an image by cutting a light section of the cornea using slit light, and the like.

  Further, the visual function testing device according to the embodiment may be a dedicated device for subjective optometry including a glare test and a contrast test (see, for example, Patent Documents 1 and 3). Furthermore, the visual function testing device according to the embodiment may have a configuration capable of performing subjective optometry as a single device (see, for example, Patent Document 3), or may be configured to be used with other devices in subjective optometry. Good (see, for example, Patent Document 1).

[Overview]
Several examples of the information presented to the subject by the visual function testing device according to the embodiment and the configuration therefor will be schematically described. The information presented to the subject includes a target (chart) and glare light. A specific configuration of the apparatus for presenting these pieces of information will be described later. In addition, any two or more of the examples described below can be arbitrarily combined. In the following example, description will be made using the direction when the direction from the subject toward the visual function testing device is used as a reference.

(First example)
A first example is shown in FIG. FIG. 1 shows a schematic configuration of the front surface (surface facing the eye to be examined) of the visual function testing device 100 according to this example. An optotype presenting unit 110 and a pair of light source units 121 and 122 are provided on the front surface of the visual function testing device 100. The light source unit 121 is arranged on the left side of the optotype presenting unit 110, and the light source unit 122 is arranged on the right side of the optotype presenting unit 110.

  The optotype presenting unit 110 is provided, for example, in the central portion of the front surface of the visual function testing device 100, and the eye to be examined is arranged at a position facing the optotype presenting unit 110 during the examination. The optotype presenting unit 110 can present the optotype group arranged along the left-right direction.

  Note that the optotype presenting unit 110 does not need to be provided on the front surface of the visual function testing device 100, and deflects the light beam forming the optotype by a reflecting member or the like, for example, as in the configuration disclosed in Patent Document 1. Accordingly, the target may be presented on the front of the eye to be examined. Further, as in the configuration described later, a configuration in which a target is projected onto the eye to be examined using a refractive optical system including a lens or the like may be used.

  The optotype presenting unit 110 of this example is provided with four optotype presenting areas 111, 112, 113, and 114 in order from the top to the bottom. In each of the target presentation areas 111 to 114, a target group composed of two targets is presented.

  Each target group shown in FIG. 1 includes a contrast target used for glare inspection (contrast glare inspection). Note that the type of the target included in the target group is not limited to the contrast target. For example, the target group may include any type of target applicable to the glare inspection, such as a Landolt ring or a character target.

  The optotype presenting unit 110 includes an arbitrary configuration. For example, the target presentation unit 110 may include a target drawing unit that draws a plurality of targets and a light emitting unit provided on the back side thereof. Examples of the target drawing means include a liquid crystal panel capable of displaying a target and a sheet on which a target design is drawn in advance. The light emitting means includes an arbitrary light source. It should be noted that the visual target drawing means and the light emitting means may be individually configured or may be integrated.

  The light source unit 121 provided on the left side of the optotype presenting unit 110 will be described. The light source unit 121 is used for irradiating glare light toward the eye to be examined. The light source unit 121 is arranged at a position left by a predetermined distance in the left direction from the visual target arranged on the leftmost side among the visual target groups presented on the visual target presenting unit 110.

  The predetermined distance may be a fixed value or a variable value (a variable case will be described later). When the predetermined distance is a fixed value, the fixed value is set so that the visual target and the glare light form a visual angle of 7 degrees, for example. When the predetermined distance is variable, the variable range is set to an arbitrary range including, for example, the above-described visual degree of 7 degrees.

  The light source unit 122 provided on the right side of the optotype presenting unit 110 will be described. Similar to the light source unit 121, the light source unit 122 is used to irradiate glare light toward the eye to be examined. The light source unit 122 is disposed at a position that is a predetermined distance in the right direction from the visual target disposed on the rightmost side among the visual target group presented by the visual target presenting unit 110. This predetermined distance is substantially equal to the distance between the target group and the light source unit 121 (that is, the “predetermined distance” in the description regarding the light source unit 121). Specifically, the two predetermined distances may be included in a range that satisfies the requirements for the appropriateness (accuracy, accuracy, etc.) of the glare inspection, and / or within a tolerance in manufacturing of the device. May be included.

  The light sources 121 and 122 do not need to be provided on the front surface of the visual function testing device 100. For example, as in the configuration disclosed in Patent Document 1, the eye to be examined is deflected by a reflective member or the like. It may be the composition which irradiates glare light from the front. Moreover, the structure which irradiates glare light to a to-be-examined eye using the refractive optical system containing a lens etc. like the structure mentioned later may be sufficient.

  Each of the light source units 121 and 122 may include one or more surface light sources. Examples of the surface light source include a fluorescent lamp and an organic EL panel. Moreover, the structure which irradiates the to-be-examined eye with the light from a point light source via a diffuser can also be used as a surface light source.

  In this example, each of the light source parts 121 and 122 has a light emitting surface whose longitudinal direction is the arrangement direction (vertical direction) of the four visual target presenting areas 111 to 114. The length of the light emitting surface may exceed the arrangement length of the four visual target presenting areas 111 to 114. That is, the upper end of the light emitting surface is positioned above the upper end of the uppermost visual target presentation area 111, and the lower end of the light emitting surface is positioned lower than the lower end of the lowermost visual target presenting area 114. May have been. In particular, in the case where a plurality of target presentation areas are provided, the effect of glare light on all the targets can be made the same level by applying this configuration.

  When a surface light source is used, the distribution of light emission luminance of the surface light source may be substantially uniform or intentionally non-uniform. When the light emission luminance distribution is made substantially uniform, the effect of glare light on all the targets can be made the same level.

  On the other hand, a configuration in which the light emission luminance distribution of the surface light source is intentionally non-uniform is effective when, for example, it is desired to divide all the targets into two or more and apply glare light with different brightness. For example, the upper half of each of the light source units 121 and 122 emits light with a relatively high luminance, and the lower half emits light with a relatively low luminance, thereby comparing the targets shown in the target presentation areas 111 and 112. Bright glare light can be applied, and relatively dark glare light can be applied to the target presented in the target presentation regions 113 and 114. Even in such a case, it is desirable that the effect of glare light be given to one or more targets included in each set to the same extent. Specifically, in the light source units 121 and 122, it is desirable that portions having the same vertical position (height position) output light having substantially the same brightness.

(Second example)
A second example is shown in FIG. Note that any of the configurations described in the first example can be applied to the second example. FIG. 2 shows a schematic configuration of the front surface of the visual function testing device 200 according to this example. An optotype presenting unit 210 and a pair of light source units 221 and 222 are provided on the front surface of the visual function testing device 200. The light source unit 221 is disposed on the left side of the visual target presenting unit 210, and the light source unit 222 is disposed on the right side of the visual target presenting unit 210.

  The optotype presenting unit 210 has the same configuration as that of the optotype presenting unit 110 in the first example, and includes four visual target presenting areas 211, 212, 213, and 214 in order from the top to the bottom.

  The light source unit 221 is used for irradiating glare light toward the eye to be examined. The light source unit 221 is disposed at a position left by a predetermined distance in the left direction from the visual target disposed on the leftmost side among the visual target group presented by the visual target presenting unit 210. This predetermined distance may be a fixed value or a variable value.

  Similar to the light source unit 221, the light source unit 222 is used for irradiating glare light toward the eye to be examined. The light source unit 222 is disposed at a position that is a predetermined distance in the right direction from the target disposed on the rightmost side in the target group presented by the target presenting unit 210. This predetermined distance is substantially equal to the distance between the target group and the light source unit 221.

  The light source unit 221 includes a plurality of light sources 221i (i = 1 to k, k ≧ 2) arranged in the vertical direction. Similarly, the light source unit 222 includes a plurality of light sources 222i (i = 1 to k, k ≧ 2) arranged in the vertical direction. Examples of the light sources 221i and 222i include a light emitting diode (LED), an organic EL light source, an incandescent lamp, and a (bulb-shaped) fluorescent lamp. The light sources 221i and 222i may be arbitrary light sources, and may be point light sources or surface light sources, for example.

  The plurality of light sources 221i and the plurality of light sources 222i have an array corresponding to each other. For example, if the symbols i = 1 to k of the plurality of light sources 221i and 222i are sequentially attached from the upper side to the lower side, the light source 221i and the light source 222i have the same position (the same in the vertical direction) for each of the symbols i. (Height position). Further, each of the plurality of light sources 221i and the plurality of light sources 222i may be arranged at equal intervals or may be arranged at non-equal intervals.

  The arrangement intervals of the plurality of light sources 221i and the plurality of light sources 222i correspond to, for example, the arrangement intervals of the target presentation areas 211 to 214 (that is, the arrangement intervals of the four target groups arranged in the vertical direction). It may be. For example, the pitch of the arrangement of the plurality of target groups in the vertical direction may be an integral multiple of the pitch of the arrangement of the plurality of light sources 221i (and 222i).

  The arrangement length of the plurality of light sources 221i may exceed the arrangement length of the four target presentation areas 211 to 214. That is, among the plurality of light sources 221i, the light source located at the upper end is located above the upper end of the uppermost target presentation area 211, and the light source located at the lower end from the lower end of the lowermost target presentation area 214. Also, it may be configured to be positioned below. The same applies to the arrangement length of the plurality of light sources 222i. In particular, in the case where a plurality of target presentation areas are provided, the effect of glare light on all the targets can be made the same level by applying this configuration.

  The light emission luminance of the plurality of light sources 221i and 222i may be substantially uniform or intentionally non-uniform. When the light emission luminance is made substantially uniform, the effect of glare light on all the targets can be made the same level.

  On the other hand, the configuration in which the light emission luminances of the plurality of light sources 221i and 222i are intentionally non-uniform is effective when, for example, it is desired to divide all the targets into two or more and apply glare light with different brightness. is there. For example, when an even number (2m) of light sources 221i and an even number (2m) of light sources 222i are provided, the upper half m light sources 221i and the upper half m light sources 222i have relatively high luminance. And the lower half m light sources 221i and the lower half m light sources 222i emit light with a relatively low luminance, so that the targets shown in the target display regions 211 and 212 are relatively bright. Glare light is applied, and relatively dark glare light can be applied to the visual target presented in the visual target presenting regions 213 and 214. Even in such a case, it is desirable that the effect of glare light be given to one or more targets included in each set to the same extent. Specifically, it is desirable that the light sources 221i and 222i having the same vertical position (height position) output light having substantially the same brightness.

(Third example)
A third example is shown in FIG. Note that any of the configurations described in the first example or the second example can be applied to the third example. FIG. 3 shows a schematic configuration of the front surface of the visual function testing device 300 according to this example. An optotype presenting unit 310 and a pair of light source units 321 and 322 are provided on the front surface of the visual function testing device 300. The light source unit 321 is disposed on the left side of the visual target presenting unit 310, and the light source unit 322 is disposed on the right side of the visual target presenting unit 310.

  The optotype presenting unit 310 has the same configuration as that of the optotype presenting unit 110 in the first example, and includes four target presentation areas 311, 312, 313, and 314 in order from the top to the bottom.

  The light source unit 321 is used for irradiating glare light toward the eye to be examined. The light source unit 321 is arranged at a position left by a predetermined distance in the left direction from the visual target arranged on the leftmost side among the visual target groups presented by the visual target presenting unit 310. This predetermined distance may be a fixed value or a variable value.

  Similar to the light source unit 321, the light source unit 322 is used to irradiate glare light toward the eye to be examined. The light source unit 322 is disposed at a position that is a predetermined distance in the right direction from the visual target disposed on the rightmost side among the visual target group presented by the visual target presenting unit 310. This predetermined distance is substantially equal to the distance between the target group and the light source unit 321.

  The light source unit 321 includes two or more light sources 321i (i = 1 to k, k ≧ 2) arranged in the vertical direction. Similarly, the light source unit 322 includes two or more light sources 322i (i = 1 to k, k ≧ 2) arranged in the vertical direction. Examples of the light sources 321i and 322i include a light emitting diode (LED), an organic EL light source, an incandescent lamp, and a (bulb-shaped) fluorescent lamp. The light sources 321i and 322i may be arbitrary light sources, and may be point light sources or surface light sources, for example. Each of the two or more light sources 321i and the two or more light sources 322i may be arranged at equal intervals, or may be arranged at non-equal intervals. The light emission luminance of the two or more light sources 321i and the two or more light sources 322i may be substantially uniform or intentionally non-uniform.

  The arrangement length of the two or more light sources 321i may be shorter than the arrangement length of the four visual target presenting areas 311 to 314. In particular, the arrangement length of the two or more light sources 321i may be sufficiently shorter than the arrangement length of the four target presentation areas 311 to 314, for example, 4 of the arrangement length of the four target presentation areas 311 to 314. It may be about 1 / minute (that is, it may be about the same as the length of one target presentation area in the vertical direction). The same applies to the arrangement length of the plurality of light sources 322i.

  The light source unit 321 is moved by the driving unit 331 in the arrangement direction of the four target presentation areas 311 to 314 (vertical direction, the direction indicated by the bidirectional arrow A in FIG. 3). As an example of a specific configuration for that purpose, the light source unit 321 is fitted to a rail whose longitudinal direction is the vertical direction. The drive unit 331 includes an actuator (such as a pulse motor) whose operation is controlled by an arithmetic control unit, which will be described later, and a mechanism that converts a force generated by the actuator into a force that moves the light source unit 321 along the rail. May be. Alternatively, the drive unit 331 includes an operation unit (handle, knob, dial, etc.) that accepts a manual operation, and a mechanism that converts the force applied to the operation unit into a force that moves the light source unit 321 along the rail. You can leave. Similarly, the light source unit 322 is moved in the vertical direction by the driving unit 332.

  The driving unit 331 and the driving unit 332 can be configured to perform linked operations. This linkage operation is, for example, an operation of moving the light source unit 321 and the light source unit 322 up and down in a state where they are arranged at substantially the same height position. That is, this linkage operation is an operation of moving the light source unit 321 and the light source unit 322 simultaneously in the same direction and at the same speed, and when the operation is stopped at an arbitrary timing, the light source unit 321 and the light source unit 321 The operation may be such that 322 are arranged at substantially the same height.

  Control that can be executed by the visual function testing device 300 according to this example will be described. The control at each stage is executed by an arithmetic control unit described later. First, a target group is presented in each of the target presentation areas 311 to 314, the light source unit 321 is arranged at the left position of the target presentation area 311, and the light source unit 322 is arranged at the right position. In this state, a glare test using the optotype group presented in the optotype presentation area 311 is performed. The examiner or the subject inputs the response content of the subject with respect to the target group. Upon receiving this input (or receiving an instruction to shift to the next inspection stage), the drive unit 331 moves the light source unit 321 to the left position of the target presentation area 312, and the drive unit 332 views the light source unit 322. Move to the right position of the sign presentation area 312. In this state, when the glare test using the optotype group presented in the optotype presenting area 312 is performed and the response content of the subject is input, the drive unit 331 causes the light source unit 321 to move to the optotype presenting area. The drive unit 332 moves the light source unit 322 to the right position of the visual target presenting area 313. In this state, when the glare test using the optotype group presented in the optotype presenting area 313 is performed and the response content of the subject is input, the drive unit 331 causes the light source unit 321 to pass through the optotype presenting area. The drive unit 332 moves the light source unit 322 to the right position of the visual target presenting area 314. In this state, a glare test is performed using the optotype group presented in the optotype presentation area 314, and the response content of the subject is input. If necessary, another target group is presented in each of the target presentation areas 311 to 314, and the glare inspection is continuously performed in the manner described above.

  Another control example will be described. In the above control example, the inspection is performed in a state in which the target group is presented in all the target presentation areas 311 to 314. On the other hand, the target group is selectively presented in any one of the target presentation areas 311 to 314, and the light source unit 321 is moved to the left position of the target presentation area where the target group is presented. It is possible to control the drive unit 331 to control the drive unit 332 to move the light source unit 322 to the right position. Note that the selection of the target presentation area in which the target group is presented is performed, for example, in response to a user's selection instruction. Alternatively, an order is set in advance for the target presentation areas 311 to 314, and a target group switching instruction (that is, an instruction to end the current inspection step (input of response contents, etc.) to be used for the inspection, or the next In response to an instruction to shift to the inspection step, etc., it is possible to sequentially switch the target presentation area where the target group is presented according to the setting order. The selective target group presentation as described above can be executed by the target example presentation control unit 430 of the fourth example.

  According to the third example, glare light can be applied from the left position and the right position of the target group used for the examination. Accordingly, it is possible to apply the same degree of glare light to a plurality of target groups used sequentially in the glare inspection.

(Fourth example)
A fourth example is shown in FIG. Note that any of the configurations described in any of the first to third examples can be applied to the fourth example. FIG. 4 shows a schematic configuration of the front surface of the visual function testing device 400 according to this example. An optotype presenting unit 410 and a pair of light source units 421 and 422 are provided on the front surface of the visual function testing device 400. The light source unit 421 is disposed on the left side of the visual target presenting unit 410, and the light source unit 422 is disposed on the right side of the visual target presenting unit 410.

  The optotype presenting unit 410 has the same configuration as that of the optotype presenting unit 110 in the first example, and includes four visual target presenting areas 411, 412, 413, and 414 in order from the top to the bottom.

  The optotype presenting unit 410 is controlled by the optotype presenting control unit 430. The visual target presentation control unit 430 causes the visual target group to be presented in any of the four visual target presentation regions 411 to 414. For example, the optotype presentation control unit 430 first presents the optotype group in the topmost target presentation area 411. Further, the visual target presentation control unit 430 receives a user's selection instruction and presents a visual target group in the visual target presentation area designated by the selection instruction. Alternatively, when the order is set in advance for the visual target presentation areas 411 to 414, the visual target presentation control unit 430 instructs the switching of the visual target group to be used for the inspection (that is, the instruction to end the current inspection step). In response to (input of response contents, etc.) or an instruction to shift to the next examination step), the target presentation area where the target group is presented is sequentially switched according to the setting order.

  The light source unit 421 is used for irradiating glare light toward the eye to be examined. The light source unit 421 is arranged at a position left by a predetermined distance in the left direction from the visual target arranged on the leftmost side among the visual target groups presented on the visual target presentation unit 410. This predetermined distance may be a fixed value or a variable value.

  Similarly to the light source unit 421, the light source unit 422 is used to irradiate glare light toward the eye to be examined. The light source unit 422 is disposed at a position that is a predetermined distance in the right direction from the visual target disposed on the rightmost side among the visual target group presented by the visual target presenting unit 410. This predetermined distance is substantially equal to the distance between the target group and the light source unit 421.

  Each of the light source units 421 and 422 may include a surface light source similar to the first example. Or each of the light source parts 421 and 422 may contain the some light source arranged in the up-down direction similarly to the 2nd example. As another example, each of the light source units 421 and 422 includes a single light source or two or more light sources arranged in the vertical direction as in the third example, and is moved in the vertical direction by the driving unit. It may be configured to be possible. In this case, the drive unit is controlled so that the light source unit 421 is disposed at the left position of the visual target presenting area where the visual target group is presented and the light source unit 422 is disposed at the right position.

  According to this example, the effect of glare light on all the targets can be made the same level.

(Fifth example)
A fifth example is shown in FIG. Note that any of the configurations described in any of the first to fifth examples can be applied to the fifth example. FIG. 5 shows a schematic configuration of the front surface of the visual function testing device 500 according to this example. An optotype presenting unit 510 and a pair of light source units 521 and 522 are provided on the front surface of the visual function testing device 500. The light source unit 521 is disposed on the left side of the optotype presenting unit 510, and the light source unit 522 is disposed on the right side of the optotype presenting unit 510.

  The optotype presenting unit 510 has, for example, the same configuration as the optotype presenting unit 110 in the first example, and has four target presentation areas 511, 512, 513, and 514 in order from the top to the bottom. .

  The light source unit 521 is used for irradiating glare light toward the eye to be examined. The light source unit 521 is disposed at a position left by a predetermined distance in the left direction from the visual target disposed on the leftmost side among the visual target group presented by the visual target presenting unit 510. In this example, the predetermined distance is variable.

  Similar to the light source unit 521, the light source unit 522 is used for irradiating glare light toward the eye to be examined. The light source unit 522 is arranged at a position that is a predetermined distance in the right direction from the visual target arranged on the rightmost side among the visual target group presented by the visual target presenting unit 510. This predetermined distance is variable and is substantially equal to the distance between the target group and the light source unit 521.

  Each of the light source units 521 and 522 may include a surface light source similar to that in the first example. Or each of the light source parts 521 and 522 may contain the some light source arranged in the up-down direction similarly to the 2nd example. As another example, each of the light source units 521 and 522 includes a single light source or two or more light sources arranged in the vertical direction as in the third example, and is moved in the vertical direction by the driving unit. It may be configured to be possible. In this case, the drive unit is controlled so that the light source unit 521 is disposed at the left position of the visual target presenting area where the visual target group is presented and the light source unit 522 is disposed at the right position.

  The light source unit 521 is moved in the left-right direction (the direction indicated by the bidirectional arrow B in FIG. 5) by the drive unit 531. As an example of a specific configuration for that purpose, the light source unit 521 is fitted to a rail whose longitudinal direction is the left-right direction. The drive unit 531 includes an actuator (such as a pulse motor) whose operation is controlled by an arithmetic control unit, which will be described later, and a mechanism that converts the force generated by the actuator into a force that moves the light source unit 521 along the rail. May be. Alternatively, the drive unit 531 includes an operation unit (handle, knob, dial, etc.) that accepts a manual operation, and a mechanism that converts a force applied to the operation unit into a force that moves the light source unit 521 along the rail. You can leave. Similarly, the light source unit 522 is moved in the left-right direction by the drive unit 532. The range in which the light source units 521 and 522 are moved is set to an arbitrary range including, for example, a position where the visual target and the glare light have a viewing angle of 7 degrees.

  For example, the drive units 531 and 532 operate to move the light source units 521 and 522 in the opposite directions by the same distance. More specifically, at a certain point in time, the light source unit 521 is arranged at a position away from the visual target arranged on the leftmost side among the visual target groups presented by the visual target presentation unit 510 by a distance D1. In addition, the light source unit 522 is disposed at a position separated by a distance D1 in the right direction from the target disposed on the rightmost side among the target groups presented on the target presenting unit 510. . When an instruction for bringing the light source units 521 and 522 closer to the visual target presenting unit 510 is input (that is, when an instruction for reducing the above-described vision is input), the driving unit 531 moves the light source unit 521 in the right direction. And the driving unit 532 moves the light source unit 522 leftward by the distance d1 (or at the moving speed v1). In addition, when an instruction for moving the light source units 521 and 522 away from the visual target presenting unit 510 is input (that is, when an instruction for enlarging the vision is input), the driving unit 531 causes the light source unit 521 to move. The drive unit 532 moves the light source unit 522 to the right by the distance d2 (or at the moving speed v2). The distance d1 and the distance d2 may be equal or different, and the moving speed v1 and the moving speed v2 may be equal or different.

  According to this example, the effect of glare light on all the targets can be made the same level. Furthermore, according to this example, since the position (vision) of the glare light with respect to the target can be changed, it is possible to grasp how the scattering due to the opacity of the crystalline lens and the cornea changes depending on the position of the glare light (that is, , The angular dependence of scattering can be measured).

[Device configuration]
A configuration of the visual function testing device according to the embodiment will be described. The visual function testing device according to the embodiment can realize any one of the first to fifth examples described above, for example. Hereinafter, a configuration for projecting the visual target and the glare light through the refractive optical system will be described.

  The structural example of the visual function inspection apparatus which concerns on embodiment is shown to FIG. 6A, FIG. 6B, and FIG. 6A is a top view of the optical system of the visual function inspection device 1, FIG. 6B is a side view of the optical system, and FIG. 7 is a block diagram showing the control system. 6A and 6B are schematic views in which some optical elements (for example, a diaphragm member) unnecessary for the description of the embodiment are omitted.

  The optical system of the visual function inspection device 1 includes a projection optical system and a light receiving optical system. The optical path of the projection optical system and the optical path of the light receiving optical system are combined by a beam splitter 2 composed of a half mirror or the like.

  The projection optical system projects a visual target on the fundus of the eye E. The projection optical system projects glare light onto the fundus of the eye E. The projection optical system is used in subjective optometry (glare examination, visual acuity examination, etc.) and objective optometry (eye refractive power measurement, corneal shape measurement, etc.). The light receiving optical system is used in objective optometry. The projection optical system includes an optotype presenting unit 11, a pair of light source units 12 a and 12 b, a lens 13, and a lens 14.

  The projection optical system is configured as, for example, a Badal optical system. That is, the examination is executed in a state where the focal point of the lens 14 (objective lens) on the eye E side coincides with the focal point of the eye E on the lens 14 side.

  The target presentation unit 11 can display a target and includes a display device such as a liquid crystal display (LCD). The optotype presenting unit 11 is disposed on the optical axis of the projection optical system. The light output from the optotype presenting unit 11 (the light beam forming the visual target; referred to as the “target light beam”) is refracted by the lens 13, passes through the beam splitter 2, and is refracted by the lens 14 to the eye E. Incident. The target luminous flux incident on the eye E is refracted by the cornea or the crystalline lens and projected onto the fundus. Thereby, the optotype image is projected onto the fundus and the subject recognizes the optotype.

  The optotype presenting unit 11 functions as an example of the optotype presenting units 110, 210, 310, 410, and 510 in the first to fifth examples.

  The pair of light source parts 12a and 12b are arranged with the optotype presenting part 11 in between. When viewed from the eye E side, the light source unit 12 a is arranged on the left side of the optotype presenting unit 11, and the light source unit 12 b is arranged on the right side of the optotype presenting unit 11. Each of the light source units 12a and 12b includes, for example, a surface light source or a plurality of point light sources. Alternatively, each of the light source units 12a and 12b may include a single light source. When a plurality of point light sources are included, a configuration for moving these point light sources in the vertical direction may be provided. The same applies to the case where a single light source is included.

  The light (glare light) output from the light source unit 12a (or 12b) is refracted by the lens 13, passes through the beam splitter 2, is refracted by the lens 14, and enters the eye E. The glare light incident on the eye E is refracted by the cornea or the crystalline lens and projected onto the fundus. Thereby, glare light is projected onto the fundus.

  The light source unit 12a (12b) functions as an example of the light source units 121 (122), 221 (222), 321 (322), 421 (422), and 521 (522) in the first to fifth examples. The glare light is diffused by the turbidity of the cornea and the lens of the eye E, and affects the visual recognition state of the visual target. The light sources 12a and 12b are used in the glare test and are turned off in the normal visual test or the like.

  The optotype presenting unit 11 and the light source units 12a and 12b are configured as a single unit, for example. This unit is moved in a direction indicated by a bidirectional arrow C in FIG. 6A by a driving mechanism (not shown). This movement control is executed for diopter correction according to the refractive power of the eye E, for example. As a specific example of this movement control, the arithmetic control unit 30 moves the unit while analyzing the image obtained by the light receiving optical system photographing the fundus in a state where a predetermined target is projected. The position of the unit can be determined so that the upper visual target image becomes clear.

  The light receiving optical system includes a lens 21, a lens 22, and a photodetector 23 as shown in FIG. 6B. As described above, the light receiving optical system is used in objective optometry and the like. When a target luminous flux (for example, a circular target) is projected onto the fundus by the projection optical system, the fundus reflection light of this visual target luminous flux is refracted by the lens 14 and reflected by the beam splitter 2, and by the lenses 21 and 22. The light is refracted and forms an image on the light receiving surface of the photodetector 23. The photodetector 23 converts the light projected on the light receiving surface into an electric signal (image signal). This image signal is input to the arithmetic control unit 30. The examination data generation unit 34 of the arithmetic control unit 30 calculates the eye refractive power (spherical power, astigmatism power, astigmatism axis angle, etc.) of the eye E based on the image signal generated by the photodetector 23. This process is executed in the same manner as a conventional refractometer (see, for example, Patent Document 2).

  A control system of the visual function testing device 1 will be described. As shown in FIG. 7, the control system of the visual function testing device 1 includes an arithmetic control unit 30. Further, the visual function testing device 1 includes a user interface (UI) 50.

  The user interface 50 includes at least an operation unit. The operation unit includes hardware keys (buttons, dials, joysticks, switches, etc.) for performing various operations. When the user (examiner or subject) operates the operation unit, a signal (operation signal) corresponding to the operation content is input to the arithmetic control unit 30. The arithmetic control unit 30 executes control processing and / or arithmetic processing according to the operation signal.

  The user interface 50 may include a display unit including a display device such as an LCD. The display unit displays information under the control of the calculation control unit 30. The displayed information includes an operation screen, information on the subject, examination results, and the like. When the display unit is provided, the user interface 50 may function as a GUI. As a specific example, a touch panel is used as the display unit, and the calculation control unit 30 executes control processing and calculation processing in accordance with an operation input to the touch panel. As another example, the arithmetic control unit 30 may be configured to display a pointer or a cursor on the display unit, and the operation unit includes a pointing device for moving the pointer or the like.

  The arithmetic control unit 30 executes a control process for each part of the visual function testing device 1 and a predetermined arithmetic process. The arithmetic control unit 30 includes a microprocessor such as a CPU and a storage device (RAM, ROM, etc.). In a storage device such as a ROM, various control programs and various arithmetic programs are stored in advance. The microprocessor executes control processing and arithmetic processing according to these programs.

  The arithmetic control unit 30 includes a target presentation control unit 31, a light source control unit 32, a drive control unit 33, and an examination data generation unit 34.

  The optotype presenting control unit 31 controls the optotype presenting unit 11. The optotype presenting control unit 31 executes, for example, the optotype presenting process described in the first to fifth examples described above. This control includes, for example, a process of displaying a target and a process of changing the brightness of the target (or its background). The visual target presentation control unit 430 in the fourth example described above is an example of the visual target presentation control unit 31.

  The light source control unit 32 controls the light source units 12a and 12b. For example, the light source control unit 32 executes the control related to the glare light described in the first to fifth examples. This control includes, for example, processing for changing the brightness of glare light.

  As another control mode, the light source control unit 32 may be configured to change the wavelength of the glare light. Thereby, it is possible to acquire the influence of the glare light according to the wavelength (that is, the wavelength dependence of the influence of the glare light).

  Moreover, the light source control part 32 may be comprised so that the irradiation range of glare light may be changed. As a specific example, when the light source units 12a and 12b include a surface light source, the light source control unit 32 can change the light emitting area of the surface light source. As another specific example, when a diaphragm member is provided in the optical path of the glare light, the light source control unit 32 can change the size and position of the light transmitting part (hole) of the diaphragm member.

  The drive control unit 33 controls the drive unit 40 for moving the light source units 12a and 12b. That is, the drive control unit 33 performs movement control of the light source units 12a and 12b. The drive units 331 and 332 in the third example and the drive units 531 and 532 in the fifth example are examples of the drive unit 40.

  The inspection data generation unit 34 generates an inspection result for the eye E. For example, the examination data generation unit 34 obtains a visual acuity value (a subjective value) of the eye E based on a response of the subject in a subjective eye examination such as a glare examination. Here, the response of the subject is input by operating the user interface 50 by the subject himself or the examiner. Also in the objective optometry such as the eye refractive power measurement described above, the examination data generation unit 34 calculates the eye refractive power value (objective value) of the eye E based on the image signal input from the photodetector 23. To do.

[effect]
The effect of the visual function testing device according to the embodiment will be described.

  The visual function inspection device according to the embodiment includes an optotype presenting unit, a first light source unit, and a second light source unit. The optotype presenting unit presents the optotype group arranged along the first direction (for example, the left-right direction). The first light source unit (for example, the light source unit 121) is applied to the eye to be examined from a position that is separated from the first target disposed on one end side (for example, the left end side) in the target group by a predetermined distance along the first direction. Irradiate the first glare light toward. The second light source unit (for example, the light source unit 121) is covered from a position away from the second target arranged on the other end side (for example, the right end side) of the target group by the predetermined distance along the first direction. The second glare light is irradiated toward the optometry.

  According to such a visual function inspection device, it is possible to perform a glare inspection using a pair of light source units arranged at an equal distance from the target group. Therefore, it is possible to perform a glare inspection with each target under equivalent conditions while simultaneously presenting a plurality of targets. That is, it is possible to apply glare light so as to have a substantially equivalent effect on a target that is sequentially used in the glare inspection. Thereby, the accuracy and accuracy of the glare inspection can be improved.

  In the embodiment, the optotype presenting unit may be configured to present a plurality of optotype groups arranged along a second direction (for example, the vertical direction) orthogonal to the first direction (for example, the horizontal direction). Specifically, for example, as shown in FIG. 1, the optotype presenting units are arranged in the first direction (left-right direction) in each of a plurality of target-presentation areas arranged in the second direction (vertical direction). The target group can be presented. Furthermore, each of the 1st light source part and the 2nd light source part may be the structure containing the surface light source which makes a 2nd direction a longitudinal direction.

  According to this configuration, it is possible to perform a glare inspection with each target under equivalent conditions while simultaneously presenting a plurality of targets. Furthermore, since a plurality of targets arranged two-dimensionally can be presented, there is also an advantage that the degree of freedom of presentation of the targets is high. In addition, since a surface light source is used as the glare light source, discomfort (glare) given to the subject is reduced as compared with a conventional glare light source using a point light source.

  When the optotype presenting unit is configured to present a plurality of optotype groups arranged along a second direction (for example, the vertical direction) orthogonal to the first direction (for example, the left-right direction), the first light source Each of the unit and the second light source unit may include a plurality of light sources arranged along the second direction.

  According to this configuration, it is possible to perform a glare inspection with each target under equivalent conditions while simultaneously presenting a plurality of targets. Furthermore, there is a merit that the degree of freedom of presentation of the target is high. In addition, when each of the plurality of light sources is a surface light source, or when it is a point light source and a diffuser plate or the like is disposed in front of the light source, it reduces the discomfort (glare) given to the subject. Can be planned.

  When the optotype presenting unit is configured to present a plurality of optotype groups arranged along a second direction (for example, the vertical direction) orthogonal to the first direction (for example, the left-right direction), the following configuration It is possible to apply. First, each of the first light source unit and the second light source unit includes a single light source or two or more light sources arranged along the second direction. Furthermore, the visual function testing device includes a first drive unit that moves the first light source unit and the second light source unit in the second direction. Drive units 331 and 332 shown in FIG. 3 are examples of the first drive unit.

  According to this configuration, it is possible to appropriately change the application position of the glare light according to the position of the target currently used in the glare inspection. Therefore, it is possible to perform a glare inspection with each target under the same conditions while simultaneously presenting a plurality of targets. Furthermore, there are also merits such as an improvement in the degree of freedom of presentation of the target and a reduction in discomfort (glare) given to the subject.

  Each of the first light source unit and the second light source unit is a single light source or two or more light sources arranged along a second direction (for example, the vertical direction) orthogonal to the first direction (for example, the horizontal direction). May be included. Furthermore, the optotype presenting unit may be configured to be able to change the presentation position of the optotype group arranged in the first direction in the second direction.

  According to this configuration, since the target presentation position can be changed as appropriate, there is an advantage that the degree of freedom of presentation of the target is high.

  The visual function testing device according to the embodiment may include a second drive unit for moving each of the first light source unit and the second light source unit in a first direction (for example, the left-right direction). That is, the second drive unit has a function of moving the first light source unit and the second light source unit closer to or away from the target group presented by the target display unit.

  According to this configuration, it is possible to obtain the angle dependency of scattering caused by turbidity in the eye to be examined.

  Further, the second drive unit may be configured to move the first light source unit and the second light source unit in the opposite directions by an equal distance.

  According to this configuration, the first light source unit and the first light source unit and the first light source unit are maintained while the distance between the visual target presenting unit and the first light source unit is kept equal to the distance between the visual target presenting unit and the second light source unit. Two light source parts can be moved. Thereby, glare light from the left direction and glare light from the right direction can be applied at substantially the same angle with respect to the visual target. Therefore, the measurement of the angle dependency of scattering can be optimized.

  The optotype presenting unit may be configured to be able to change the brightness of the optotype included in the optotype group and / or the brightness of the background of the optotype group.

  According to this configuration, it is possible to measure the dependence of the visual function on the brightness of the visual target and the dependence of the visual function on the background brightness of the visual target in the glare test.

  The first light source unit may be configured to change the brightness of the first glare light, and the second light source unit may be configured to be able to change the brightness of the second glare light.

  According to this configuration, it is possible to measure the dependence of the visual function on the brightness of the glare light in the glare inspection.

  The optotype presenting unit is configured to be able to present any type of optotype that can be used in the glare examination. Examples of such targets include Landolt rings, character targets, and contrast targets.

[Modification]
The configuration described above is merely an example for favorably implementing the present invention. Therefore, arbitrary modifications (omitted, replacement, addition, etc.) within the scope of the present invention can be made as appropriate.

  In the above embodiment, the light source units are arranged on the left side and the right side of the optotype presenting unit, but the arrangement of the pair of light source units is not limited to this. For example, the light source units can be arranged on the upper side and the lower side of the optotype presenting unit, respectively. In that case, the optotype group includes a plurality of optotypes arranged in the vertical direction.

  A configuration of a modified example of the visual function testing device is shown in FIG. FIG. 8 is a top view of the optical system of the visual function inspection device 1000. This optical system is applicable instead of the configuration shown in FIG. 6A described above. The side view of the optical system may be the same as the configuration shown in FIG. 6B, and the control system may be the same as the configuration shown in FIG.

  The difference from the configuration illustrated in FIG. 6A is the position of the pair of light source units. That is, in FIG. 6A, the two light source parts 12a and 12b are arranged so as to sandwich the optotype presenting part 11, but in this modified example, the two light source parts 15a and 15b are arranged so as to sandwich the lens 14. ing.

  Moreover, in this modification, the optotype presenting unit 11 is moved in the direction indicated by the bidirectional arrow D in FIG. 8 for diopter correction. Even with the configuration according to this modification, the same effect as the above-described embodiment can be obtained.

  As another modified example, in any conventional apparatus including the apparatuses disclosed in Patent Documents 1 to 4, it is possible to replace the means for projecting the glare light with the means according to the present invention. For example, a pair of glare lamps (indicated by reference numeral 5 in FIG. 1) of the device disclosed in Patent Document 4 (referred to as a conventional device) is used as the first light source unit and the second light source according to the present invention. Part can be substituted.

  More specifically, the visual function testing device according to the present modification is different from the measurement target plate (reference numeral 4) of the conventional device in that a spot opening for forming a target, and above and below the spot opening, respectively. The measurement target plate is provided with an opening (glare opening) in which the horizontal direction is the longitudinal direction and the vertical direction is the short direction. Further, a pair of light source portions is provided immediately after the pair of glare openings. The pair of light source units may have any configuration of the above embodiment. According to such a configuration, it is possible to apply the visual target and the glare light to the eye to be examined in the manner shown in FIGS. When a mechanism for changing the distance between the pair of light source units is provided (see FIG. 5), that is, a mechanism for moving the pair of light source units in the vertical direction (second drive unit) is provided. In this case, the glare opening is formed so as to have a width corresponding to the movement in the vertical direction. Here, the case where the configuration according to the present invention is applied to the conventional device disclosed in Patent Document 4 has been described in detail, but application to other devices can be realized in the same manner.

DESCRIPTION OF SYMBOLS 1,100 Visual function test | inspection apparatus 11,110 Visual target presentation part 12a, 12b, 121,122 Light source part 30 Computation control part 40 Drive part

Claims (10)

An optotype presenting unit for presenting an optotype group arranged along the first direction;
A first light source unit that emits first glare light toward a subject's eye from a position that is separated by a predetermined distance along the first direction from a first target disposed on one end side of the target group;
A second light source unit that emits second glare light toward the eye to be examined from a position separated by a predetermined distance along the first direction from a second target arranged on the other end side of the target group. And a visual function inspection device. The optotype presenting unit presents a plurality of the optotype groups arranged along a second direction orthogonal to the first direction,
Each of the said 1st light source part and the said 2nd light source part contains the surface light source which makes the said 2nd direction a longitudinal direction. The visual function test | inspection apparatus of Claim 1 characterized by the above-mentioned. The optotype presenting unit presents a plurality of the optotype groups arranged along a second direction orthogonal to the first direction,
Each of the said 1st light source part and the said 2nd light source part contains the some light source arranged along the said 2nd direction. The visual function test | inspection apparatus of Claim 1 characterized by the above-mentioned. The optotype presenting unit presents a plurality of the optotype groups arranged along a second direction orthogonal to the first direction,
Each of the first light source unit and the second light source unit includes a single light source or two or more light sources arranged along the second direction,
The visual function testing device according to claim 1, further comprising a first drive unit that moves the first light source unit and the second light source unit in the second direction. Each of the first light source unit and the second light source unit includes a single light source or two or more light sources arranged along a second direction orthogonal to the first direction,
The visual function testing device according to claim 1, wherein the visual target presenting unit is capable of changing a presentation position of the visual target group in the second direction. The view according to any one of claims 1 to 5, further comprising a second drive unit for moving each of the first light source unit and the second light source unit in the first direction. Functional inspection device. The visual function testing device according to claim 6, wherein the second driving unit moves the first light source unit and the second light source unit by an equal distance in opposite directions. The said optotype presenting part can change the brightness of the optotype included in the optotype group and / or the brightness of the background of the optotype group. The visual function testing device according to any one of the above. The first light source unit can change the brightness of the first glare light,
The visual function testing device according to any one of claims 1 to 8, wherein the second light source unit is capable of changing a brightness of the second glare light. The visual function testing device according to any one of claims 1 to 9, wherein the target group includes a Landolt ring, a character target, or a contrast target.