Optometer and optometry program

Abstract

To provide an optometer and an optometry program capable of efficiently examining the eye to be tested.SOLUTION: An optometer for examining the eye to be tested includes: target presenting means for presenting an examination target to the eye to be tested; operating means for the eye to be tested to visualize and operate the examination target and having an answer input part inputting answers to the examination target and an invisible input part inputting that the examination target cannot be visualized; and change control means which controls the target presenting means and changes the examination target to an examination target of different eyesight value when a first operation signal is inputted from the answer input part and a prescribed answer reaches first set frequency. The change control means skips remaining frequency of the first set frequency to control the target presenting means even though the prescribed answer does not reach the first set frequency when a second operation signal is inputted from the invisible input part, and changes the examination target to an examination target of different eyesight value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an ophthalmic apparatus and an ophthalmic program for examining an eye to be examined.

Background Art

[0002] As an ophthalmic apparatus, there is known a visual acuity examination apparatus that measures the visual function (e.g., visual acuity, etc.) of an eye to be examined by having the subject look into a presentation window and confirm an examination target (see Patent Document 1). In addition, there is known a subjective ophthalmic apparatus that measures the optical characteristics (e.g., refractive power of the eye, etc.) of an eye to be examined by arranging an optical member in front of the subject's eye and presenting an examination target to the eye to be examined through the optical member (see Patent Document 2). Recently, so-called self-ophthalmoscopy in which the subject himself / herself performs ophthalmic examination has also been carried out.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional ophthalmic apparatus, when a correct answer or an incorrect answer (e.g., a wrong answer or unrecognizable, etc.) to an examination target by the subject is obtained a certain number of times, the visual acuity value of the examination target is changed. However, with the ophthalmic apparatus configured in this way, for example, even when the subject cannot recognize the examination target at all, the subject has to repeat the answer, resulting in a problem of a long examination time.

[0005] In view of the above prior art, an object of the present disclosure is to provide an ophthalmic apparatus and an ophthalmic program capable of efficiently examining an eye to be examined.

Means for Solving the Problems

[0006] In order to solve the above problems, the present disclosure is characterized by having the following configuration. (1) The ophthalmic apparatus according to the first aspect of the present disclosure is an ophthalmic apparatus for examining an eye to be examined, and includes a target presenting means for presenting an examination target to the eye to be examined, and an operation means for the subject to visually recognize and operate the examination target, the operation means having a response input unit for inputting a response to the examination target and a non-visual recognition input unit for inputting that the examination target cannot be visually recognized, and change control means for controlling the target presenting means to change the examination target to an examination target with a different visual acuity value when a first operation signal is input from the response input unit and a predetermined response reaches a first set number of times. The change control means is characterized in that when a second operation signal is input from the non-visual recognition input unit, even if the predetermined response has not reached the first set number of times, the remaining number of times of the first set number of times is skipped, and the target presenting means is controlled to change the examination target to an examination target with a different visual acuity value. (2) The ophthalmic program according to the second aspect of the present disclosure has a target presenting means for presenting an examination target to an eye to be examined, and an operation means for the subject to visually recognize and operate the examination target, the operation means having a response input unit for inputting a response to the examination target and a non-visual recognition input unit for inputting that the examination target cannot be visually recognized, and is an ophthalmic program used in an ophthalmic apparatus for examining the eye to be examined. When the ophthalmic program is executed by a processor, the ophthalmic apparatus is caused to execute a change control step of controlling the target presenting means to change the examination target to an examination target with a different visual acuity value when a first operation signal is input from the response input unit and a predetermined response reaches a first set number of times. The change control step is characterized in that when a second operation signal is input from the non-visual recognition input unit, even if the predetermined response has not reached the first set number of times, the remaining number of times of the first set number of times is skipped, and the target presenting means is controlled to change the examination target to an examination target with a different visual acuity value.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0008] <Summary> The outline of the ophthalmic device according to the embodiment of the present disclosure will be described. Note that the items classified in the following <> can be used independently or in combination.

[0009] The ophthalmic device of the present embodiment is an ophthalmic device for examining an eye to be examined. For example, the ophthalmic device may be an ophthalmic device for measuring the optical characteristics of the eye to be examined. For example, the optical characteristics of the eye to be examined may be at least any one of eye refractive power (for example, spherical power, cylindrical power, astigmatic axis angle, etc.), visual function, binocular visual function (for example, prism amount, stereoscopic visual function, etc.), contrast sensitivity, etc.

[0010] For example, the ophthalmic device may be a visual acuity test device that measures the eye to be examined by having the subject look into the presentation window and confirm the test target presented in the target window inside the housing. Also, for example, the ophthalmic device may be a subjective ophthalmic device that projects a target light beam toward the eye to be examined and measures the eye to be examined by changing the optical characteristics of the target light beam. Note that the ophthalmic device may have a target presentation means, an operation means, a correction means, etc., which will be described later.

[0011] <Target Presentation Means> The ophthalmic apparatus of the present embodiment may include a target presenting means. The target presenting means presents a test target to the eye to be examined. For example, the test target may be a target with a directionality for the subject to distinguish directions (e.g., Landolt ring target, tumbling E target, etc.), a character target for the subject to read characters (e.g., hiragana target, katakana target, alphabet target, etc.), a numeric target for the subject to identify numbers, or at least any one of the like.

[0012] For example, the target presenting means may be a display (e.g., display 31). Also, for example, the target presenting means may be a light source and a DMD (Digital Micromirror Device). Also, for example, the target presenting means may be a light source and a target plate.

[0013] For example, the target light beam from the target presenting means may be directly emitted toward the eye to be examined. Also, for example, the target light beam from the target presenting means may be indirectly guided toward the eye to be examined through a projection optical system (e.g., projection optical system 30). For example, the projection optical system may have at least one optical member for allowing the target light beam emitted from the target presenting means to pass therethrough. As an example, it may have at least any one of a lens, a mirror, etc.

[0014] <Operation means> The ophthalmic apparatus of the present embodiment may include an operation means (e.g., subject controller 20). The operation means is an operation means for the subject to visually recognize and operate on the test target, and has a response input unit (e.g., response lever 21) for inputting a response to the test target, and a non-visible input unit (e.g., response button 22) for inputting that the test target cannot be visually recognized. For example, the response input unit and the non-visible input unit may be configured such that the subject can input an operation signal, and at least any one of a mouse, a keyboard, a touch panel, a controller, etc., as a user interface can be used.

[0015] For example, the response input unit of the operation means may be a response input unit for inputting a number or the like assigned to the test target. Also, for example, the response input unit of the operation means may be a response input unit for inputting the direction of the test target. For example, in this case, the response input unit may be configured to enable input in a plurality of predetermined directions. As an example, it may be possible to input in four directions: up, down, left, and right. In other words, it may be possible to input angles of 0° (360°), 90°, 180°, and 270°. Of course, the plurality of predetermined directions may be four directions different from up, down, left, and right (as an example, diagonal directions such as upper left, lower left, upper right, lower right, etc.).

[0016] <Correction means> The ophthalmic apparatus of the present embodiment may include correction means. The correction means changes the optical characteristics of the target light beam emitted from the target presenting means. For example, the optical characteristics of the target light beam may be at least any one of the spherical power, cylindrical power, astigmatic axis angle, etc. of the target light beam.

[0017] The correction means may include a correction optical system as a part of the correction means. For example, the correction optical system may change the optical characteristics of the target light beam by being disposed in the optical path of the projection optical system.

[0018] The correction optical system may be configured to be able to change the optical characteristics of the target light beam. For example, the correction optical system may change the spherical power of the target light beam by optically changing the presentation distance of the test target to the eye to be examined. Also, for example, the correction optical system may change at least any one of the spherical power, cylindrical power, astigmatic axis angle, etc. of the target light beam by controlling the optical element. As an example, the optical element may be at least any one of a spherical lens, a cylindrical lens, a cross cylinder lens, a rotary prism, a wavefront modulation element, a variable focus lens, etc. Of course, it may be an optical element different from these optical elements. Note that the correction optical system may be a configuration that combines a configuration for changing the presentation distance of the test target and a configuration for controlling the optical element.

[0019] Further, for example, the corrective optical system may be an eye refractive power measurement unit (e.g., the eye refractive power measurement unit 40) that arranges an optical element in front of the eye to be examined. For example, the eye refractive power measurement unit may have a variable focus lens and be configured to change the refractive power of the variable focus lens. Also, for example, the eye refractive power measurement unit may include a lens disk on which a plurality of optical elements are arranged on the same circumference, and a driving means (e.g., a motor) for rotating the lens disk, and be configured to electrically switch the optical elements by driving the driving means. Of course, the eye refractive power measurement unit may be configured to have a variable focus lens, a lens disk, and a driving means.

[0020] Further, for example, the corrective optical system may be configured to change the optical characteristics of the target light beam by arranging an optical element between a target presenting means and an optical member for guiding the target light beam emitted from the target presenting means, and controlling the optical element. That is, the corrective optical system may be configured as a phantom lens refractometer (phantom corrective optical system).

[0021] <Setting means> The ophthalmic apparatus of the present embodiment may include a setting means (e.g., the control unit 60). The setting means sets a first set number for determining the presence or absence of the visual acuity of the eye to be examined based on a first operation signal from the answer input unit in the operation means. For example, the setting means may be able to set an arbitrary number of times by the examiner as the first set number, or may be able to select one value from a plurality of set values (preset values) as the first set number. Note that, for example, the first set number may be once, or a plurality of times of two or more times. Also, for example, the first set number may be the number of "correct answers" to the test targets of the subject to be examined, or may be the number of "incorrect answers" to the test targets of the subject to be examined.

[0022] Further, the setting means sets a second set number for determining the non-visibility of the test target based on the second operation signal from the non-visible input section in the operation means. For example, the setting means may set any number of times by the examiner as the second set number, or may select one value from a plurality of set values (preset values) as the second set number. Note that, for example, the first set number may be once, or a plurality of times of two or more times.

[0023] For example, the setting means (first setting means) for setting the first set number and the setting means (second setting means) for setting the second set number may be provided as separate configurations, or may be provided as a configuration that shares each other.

[0024] <Change control means> The ophthalmic apparatus of the present embodiment may include change control means (for example, control unit 60). When a first operation signal is input from the answer input section of the operation means and a predetermined answer reaches the first set number, the change control means controls the target presenting means to change the test target to a test target with a different visual acuity value. For example, the first set number may be the number of times set for determining the presence or absence of the visual acuity of the eye to be examined. As an example, the first set number may be the number of "correct answers" for the test target of the subject, or the number of "incorrect answers" for the test target of the subject. Further, for example, the first set number may be a fixed value set in advance, or a variable value that can be changed by the above-described setting means.

[0025] For example, when a second operation signal is input from the non-visible input unit of the operation means, the change control means may skip the remaining number of times of the first set number even if a predetermined answer has not reached the first set number, and control the visual target presenting means to change the test visual target to a test visual target with a different visual acuity value. For example, the second set number may be a fixed value set in advance, or a variable value that can be changed by the above-mentioned setting means. Thereby, for example, even when the subject determines that the test visual target is "unknown", the visual acuity value of the test visual target can be switched without repeating the input until the total number of correct or incorrect answers is reached, so that the test time can be shortened. In addition, the number of times the subject inputs an answer of "unknown" is reduced, and the operational burden and psychological burden on the subject can be reduced.

[0026] For example, when the input of the second operation signal from the non-visible input unit of the operation means reaches the second set number set by the setting means, the change control means may skip the remaining number of times of the first set number and control the visual target presenting means to change the test visual target to a test visual target with a different visual acuity value. Thereby, for example, when the second set number is a small number, the examination of the test eye can be advanced more efficiently. Also, for example, when the second set number is a large number, the possibility that the subject accidentally inputs an answer of "unknown" is considered, and the examination of the test eye can be advanced more accurately.

[0027] For example, when the second set number preset in the ophthalmic apparatus or the second set number set by the above-mentioned setting means is two or more, the change control means may skip the remaining number of times of the first set number when the second operation signals from the non-visible input unit are continuous. For example, thereby, it is possible to more accurately detect that the subject has determined that the test visual target is non-visible. That is, for example, it becomes easier to detect that the subject's operation of the non-visible input unit because the test visual target cannot be visually recognized is not an erroneous operation. Therefore, the examination of the test eye can be advanced more accurately.

[0028] In addition, in the present embodiment, the second set number for the input of the second operation signal from the invisible input unit may be set to a smaller number than the first set number for the input of the first operation signal from the answer input unit. In this case, the method of proceeding with the eye examination can be appropriately switched between the case where the subject views the examination target and inputs an answer such as a number or a direction, and the case where the subject inputs an answer without being able to view the examination target. As a result, the examination can be efficiently advanced and the time can be shortened.

[0029] Further, in the present embodiment, when the answer input unit of the operation means is an answer input unit for inputting the direction of the examination target, the change control means controls the target presentation means to change the examination target to an examination target with a different visual acuity value and a different direction when a first operation signal is input from the answer input unit and a predetermined answer reaches the first set number. Even when a second operation signal is input from the invisible input unit and the predetermined answer has not reached the first set number, the remaining number of times of the first set number may be skipped, and the target presentation means may be controlled to change the examination target to an examination target with a different visual acuity value and a different direction. Thereby, when the examination target has a direction, the subject can input an answer by an intuitive operation, and since the visual acuity value and the direction are changed when the examination target is switched, it becomes difficult to remember the direction of the examination target.

[0030] Further, in the present embodiment, when the ophthalmic apparatus includes a correction means, the change control means controls the correction means to change the first correction degree to a different second correction degree when a first operation signal is input from the answer input unit and a predetermined answer reaches the first set number in a state where the eye to be examined is corrected by the correction means with the first correction degree. Even when a second operation signal is input from the invisible input unit and the predetermined answer has not reached the first set number, the remaining number of times of the first set number may be skipped, and the correction means may be controlled to change the first correction degree to a different second correction degree. For example, thereby, even when obtaining the complete correction value or the prescription value of the eye to be examined, when the subject determines that the examination target is "unknown", the correction degree can be appropriately switched without repeating the input until the total number of correct or incorrect answers is reached. Therefore, the examination time of the eye to be examined can be shortened.

[0031] Note that the present disclosure is not limited to the apparatus described in this embodiment. For example, terminal control software (program) that performs the functions of the following embodiments can be supplied to a system or apparatus via a network or various storage media, etc., and a control device (e.g., CPU, etc.) of the system or apparatus reads and executes the program.

[0032] <Example> An example of the ophthalmic apparatus in this embodiment will be described. In this example, the left - right direction of the ophthalmic apparatus is represented as the X - direction, the up - down direction as the Y - direction, and the front - back direction as the Z - direction.

[0033] FIG. 1 is an external view of the ophthalmic apparatus 100. FIG. 1(a) shows a state where the eye refractive power measurement unit 40 is supported at the standby position. FIG. 1(b) shows a state where the eye refractive power measurement unit 40 is supported at the measurement position. For example, the ophthalmic apparatus 100 includes a housing 1, a presentation window 2, a speaker 3, a holding unit 4, an examiner controller 10, a subject controller 20, an eye refractive power measurement unit 40, etc.

[0034] The housing 1 has a light - projecting optical system 30 inside. The presentation window 2 transmits the target light beam from the light - projecting optical system 30. The target light beam is projected onto the subject's eye E through the presentation window 2. When the eye refractive power measurement unit 40 is disposed between the subject's eye E and the presentation window 2 (see FIG. 1(b)), the target light beam is projected onto the subject's eye E through the presentation window 2 and an inspection window 43 described later. Thereby, an inspection target is presented to the subject's eye E. The speaker 3 outputs voice guidance, etc.

[0035] The holding unit 4 holds the eye refractive power measurement unit 40. For example, the holding unit 4 moves the arm by driving a drive unit (motor, etc., not shown), thereby moving the eye refractive power measurement unit 40 connected to the arm. Thereby, the standby position and the measurement position of the eye refractive power measurement unit 40 are switched.

[0036] The examiner's controller 10 is used for the examiner to operate the subjective ophthalmic apparatus 100. The examiner's controller 10 includes a switch unit 11, a monitor 12, etc. The switch unit 11 inputs signals for performing various settings (for example, the movement of the eye refractive power measurement unit 40, etc.). The monitor 12 displays various information (for example, the measurement results of the eye to be examined E, etc.). Note that the monitor 12 may function as a touch panel that also serves as the switch unit 11. The operation signal from the examiner's controller 10 is output to the control unit 60 by wired communication or wireless communication.

[0037] The subject's controller 20 is used to input the subject's answers. The subject's controller 20 includes a response lever 21, a response button 22, etc. The response lever 21 is used when the subject inputs the direction with respect to the test target. For example, the operation signals in the four directions of up, down, left, and right corresponding to the direction of the break of the ring of the Landolt ring target can be input by a tilting operation. The response button 22 is used when the subject does not select the direction with respect to the test target. For example, the operation signal indicating that the test target cannot be visually recognized can be input by a pressing operation. The operation signal from the subject's controller 20 is output to the control unit 60 by wired communication or wireless communication.

[0038] <Light projection optical system> Figure 2 is a schematic diagram of the light projection optical system 30. Figure 2(a) shows the optical arrangement during distance vision testing. Figure 2(b) shows the optical arrangement during near vision testing. The light projection optical system 30 projects a target light beam toward the eye to be examined E. For example, the light projection optical system 30 includes a display 31, a plane mirror 32, a concave mirror 33, a near / far switching unit 34, etc.

[0039] The display 31 displays targets (for example, fixation targets, test targets, etc.). By forming an image of the target light beam emitted from the display 31 on the fundus of the eye to be examined E, the target is presented to the eye to be examined E. For example, the display 31 may be an LCD (Liquid Crystal Display), an organic EL (Electro Luminescence), a plasma display, etc.

[0040] The plane mirror 32 reflects the target light beam from the display 31 and guides it to the concave mirror 33. Also, the plane mirror 32 reflects the target light beam from the display 31 and guides it to the eye under test E. For example, the plane mirror 32 is arranged such that the distance (presentation distance) from the eye under test E to the display 31 is optically 40 cm during the near vision test of the eye under test E. Note that instead of the plane mirror 32, it is also possible to use a reflecting member such as a prism, a beam splitter, or a half mirror.

[0041] The concave mirror 33 reflects the target light beam from the display 31 and guides it to the plane mirror 32. For example, the concave mirror 33 is arranged such that the distance (presentation distance) from the eye under test E to the display 31 is optically 5 m during the far vision test of the eye under test E. Note that instead of the concave mirror 33, it is also possible to use a reflecting member such as an aspherical mirror or a freeform mirror. Also, instead of the concave mirror 33, it is possible to use a lens or the like.

[0042] The near / far switching unit 34 switches the arrangement of the display 31 during the far vision test and the near vision test of the eye under test E. For example, the near / far switching unit 34 moves the holding unit by driving a driving unit (such as a motor) (not shown), thereby moving the display 31 held by the holding unit. As a result, the far vision arrangement and the near vision arrangement of the display 31 are switched.

[0043] For example, during the far vision test of the eye under test E, the display screen of the display 31 faces the back surface of the housing 1 (see Fig. 2(a)). The target light beam from the display 31 enters the plane mirror 32 passing through the optical axis L1, and is reflected by the plane mirror 32 in the direction of the optical axis L2. Also, it enters the concave mirror 33 passing through the optical axis L2, and is reflected by the concave mirror 33 in the direction of the optical axis L3. Also, it enters the plane mirror 32 passing through the optical axis L3, and is reflected by the plane mirror 32 in the direction of the optical axis L4. As a result, on the eye under test E, the target light beam that has passed through each optical member inside the housing 1 and is emitted outside the housing 1 is projected.

[0044] For example, during the near vision examination of the eye E to be examined, the display screen of the display 31 faces the upper surface of the housing 1 (see Fig. 2(b)). The target light beam from the display 31 enters the plane mirror 32 through the optical axis L3, and is reflected by the plane mirror 32 in the direction of the optical axis L4. As a result, the target light beam that has passed through each optical member inside the housing 1 and is emitted outside the housing 1 is projected onto the eye E to be examined.

[0045] <Eye refractive power measurement unit (correction optical system)> Fig. 3 is a schematic diagram of the eye refractive power measurement unit 40. The eye refractive power measurement unit 40 measures the eye refractive power of the eye E to be examined subjectively. In addition, the eye refractive power measurement unit 40 is used as a correction optical system. The correction optical system is arranged in the optical path of the light projection optical system 30 and changes the optical characteristics of the target light beam. For example, the eye refractive power measurement unit 40 includes a forehead rest 41, a lens unit 42, an inspection window 43, a moving unit 44, etc.

[0046] The forehead rest 41 fixes the eye E to be examined at a predetermined inspection position by abutting against the head of the subject, and keeps the distance from the eye E to be examined to the inspection window 43 constant. The lens unit 42 has a pair of left and right lens units 42L and 42R. The lens unit 42 has inspection windows 43 (left inspection window 43L and right inspection window 43R).

[0047] The moving unit 44 adjusts the distance between the left lens unit 42L and the right lens unit 42R, and the convergence angle (inward convergence angle) between the left lens unit 42L and the right lens unit 42R. For example, the moving unit 44 adjusts the distance between the left lens unit 42L and the right lens unit 42R by driving the driving units 45 (left driving unit 45L and right driving unit 45R). Also, for example, the moving unit 44 adjusts the convergence angle between the left lens unit 42L and the right lens unit 42R by driving the driving unit 46. Note that for the detailed configuration of the moving unit 44, refer to, for example, Japanese Patent Application Laid-Open No. 2004-329345.

[0048] The lens unit 42 includes a lens disk 50 inside. The lens disk 50 has a pair of left and right lens disks, namely a left lens disk 50L and a right lens disk 50R. The lens disk 50 is rotated by the drive of a drive unit 51 (a left drive unit 51L and a right drive unit 51R). Also, the lens disk 50 arranges an aperture (or a 0D lens) and a plurality of optical elements 52 (a left optical element 52L and a right optical element 52R) on the same circumference. These optical elements are rotated by the drive of a drive unit 53 (a left drive unit 53L and a right drive unit 53R). Thereby, a desired optical element 52 is switched and arranged at a desired angle on the inspection window 43.

[0049] The lens disk 50 consists of one lens disk or a plurality of lens disks. For example, a spherical lens disk, a cylindrical lens disk, an auxiliary lens disk, etc. may be provided. As an example, the spherical lens disk may have a plurality of spherical lenses with different spherical powers (spherical refractive powers). Also, as an example, the cylindrical lens disk may have a plurality of cylindrical lenses with different cylindrical powers (cylindrical refractive powers). Also, as an example, the auxiliary lens disk may have a shielding plate, a polarizing filter, a red filter / green filter, a dispersive prism, a Maddox lens, a rotary prism, a cross cylinder lens, an auto cross cylinder lens, an alignment lens, etc. The drive unit 51 and the drive unit 53 may be provided for each lens disk.

[0050] <Control Unit> FIG. 4 is a schematic diagram of the control system of the ophthalmic device 100. For example, the control unit 60 includes a CPU (processor), a RAM, a ROM, etc. The CPU controls the drive of each part in the ophthalmic device 100. Various information is temporarily stored in the RAM. Various programs executed by the CPU are stored in the ROM. As an example, a program for realizing an application (self-ophthalmic application) that automatically advances the ophthalmic examination based on the answers input by the subject is stored. Note that the control unit 60 may be composed of a plurality of control units (that is, a plurality of processors).

[0051] Connected to the control unit 60 are a speaker 3, a display 31, an examiner controller 10, a subject controller 20, a non-volatile memory 70 (hereinafter referred to as memory 70), etc. Also connected to the control unit 60 are a drive unit of the holding unit 4, a drive unit of the telephoto / short-focus switching unit 34, a drive unit of the eye refractive power measurement unit 40 (drive units 45, 46, 51, 53), etc.

[0052] The memory 70 is a non-transitory storage medium that can retain stored content even when power supply is interrupted. For example, as the memory 70, a hard disk drive, a flash ROM, a USB memory, etc. can be used.

[0053] <Control Operation> The control operation of the ophthalmic apparatus 100 having the above configuration will be described. For example, after alignment between the eye to be examined E and the eye refractive power measurement unit 40 is performed, the ophthalmic apparatus 100 can perform self-ophthalmoscopy on the eye to be examined. For example, in self-ophthalmoscopy, as a subjective measurement of the eye to be examined, spherical aberration examination, astigmatism examination, visual acuity examination, etc. are performed in order. Of course, different examinations may be performed in self-ophthalmoscopy.

[0054] In the visual acuity examination of this embodiment, a Landolt ring target is presented to the subject at a predetermined visual acuity value. When the subject operates the response lever 21 and inputs the direction of the break of the Landolt ring target, the correctness of the direction is determined. At this time, when the number of correct answers (or incorrect answers) for a predetermined visual acuity value of the Landolt ring target reaches the first set number, the Landolt ring target is changed to a different visual acuity value. Also, when the subject operates the response button 22 and inputs "don't know" for the direction of the break of the Landolt ring target, it is determined that the Landolt ring target is unrecognizable. At this time, when the number of "don't know" for a predetermined visual acuity value of the Landolt ring target reaches the second set number, the Landolt ring target is changed to a different visual acuity value.

[0055] For example, the first set count for the input from the response lever 21 and the second set count for the input from the response button 22 are set in advance as initial set counts, but can also be changed to arbitrary values.

[0056] <Confirmation and Change of the First Set Count and the Second Set Count> FIG. 5 is an example of a display screen displayed on the monitor 12 of the examiner controller 10. FIG. 5(a) is a start screen 80 for starting the self-examination of the eye to be examined. FIG. 5(b) is a setting screen 81 for confirming or changing various settings in the self-examination of the eye to be examined.

[0057] For example, the start screen 80 is displayed as the home screen on the monitor 12 of the examiner controller 10. For example, on the start screen 80, a start button 72 for starting the self-examination of the eye to be examined, a transition button 71 for transitioning to the setting screen 81, etc. are displayed. For example, the examiner may confirm the first set count for the input from the response lever 21 and the second set count for the input from the response button 22 before starting the self-examination of the eye to be examined. For example, the examiner presses the transition button 71 located at the lower left of the start screen 80 to call the setting screen 81. The control unit 60 causes the setting screen 81 to be displayed on the monitor 12 based on the input signal from the transition button 71.

[0058] For example, on the setting screen 81, there are displayed a change button 76 for changing the voice guide language in the self-eye examination, a selection button 73 for selecting the first set number for the input from the answer lever 21, a selection button 74 for selecting the second set number for the input from the answer button 22, an OK button 75, and the like. For example, the first set number for the input from the answer lever 21 is represented by taking the total number of times the Landolt ring visual target is presented at a predetermined visual acuity value as the denominator and the number of correct answers among the total number of times as the numerator. As an example, it is represented by "1 / 2", "3 / 4", "3 / 5", etc. For example, when the selection button 73 is pressed, these numbers are shown as a drop-down list. Also, for example, the second set number for the input from the answer button 22 is represented as the number of operations of the answer button 22. For example, when the selection button 74 is pressed, the numbers from 1 to 3 are shown as a drop-down list.

[0059] The examiner operates the selection button 73 and the selection button 74, and if necessary, changes the first set number and the second set number from the initial set numbers to arbitrary set numbers. Here, an example is given where the first set number is changed to "3 / 5" and the second set number is changed to "1". Also, when the examiner changes the first set number and the second set number, the examiner presses the OK button 75 located in the lower right of the setting screen 81. When the control unit 60 receives the input signal from the OK button 75, based on this input signal, it reflects each setting and causes the start screen 80 to be displayed on the monitor 12 (that is, returns the display from the setting screen 81 to the start screen 80).

[0060] For example, the examiner sets the second set number (in other words, the number of times of "I don't know") for the input from the answer button 22 to a smaller number than the first set number (in other words, the number of correct answers) for the input from the answer lever 21. Note that the control unit 60 may limit the drop-down list so that only a number of the second set number smaller than the first set number can be selected according to the first set number selected by the examiner, so that the second set number does not become a number larger than the first set number. In other words, it may be made impossible to set a number larger than the first set number as the second set number. Alternatively, the control unit 60 may notify that the second set number is larger than the first set number by generating an audio guide or displaying a message.

[0061] <Start of Subjective Measurement for the Eye Under Test> When the examiner finishes changing the first set number for the input from the answer lever 21 and the second set number for the input from the answer button 22, the examiner presses the start button 72 on the start screen 80 to start the subjective measurement for the eye under test. The control unit 60 generates an audio guide indicating the operation method of the subject controller 20 from the speaker 3 according to the operation signal from the start button 72. In addition, the control unit 60 displays the test target on the display 31 according to the operation signal from the start button 72. Further, the control unit 60 controls the eye refractive power measurement unit 40 so as to correct the eye under test E with a predetermined correction degree (for example, spherical degree, cylindrical degree, and astigmatic axis angle), and arranges a spherical lens or a cylindrical lens in the inspection window 43. For example, the predetermined correction degree of the eye under test E may be determined based on the objective refractive power of the eye under test E, and such a correction degree is the initial value at the start of the measurement.

[0062] First, the control unit 60 performs a spherical aberration test as an examination item for subjective measurement of the eye E to be examined. For example, the spherical aberration test is a test for adjusting the spherical power set as the initial value of the eye E to be examined to an appropriate spherical power using a red-green target. The subject answers which side, the red side or the green side, of the red-green target appears clearer, or whether both appear equally clear, by operating the response lever 21 and the response button 22. For example, when the control unit 60 detects that a second operation signal has been input from the response button 22 and that the red side and the green side of the red-green target appear equally clear, it determines that the adjustment to the appropriate spherical power has been made.

[0063] Next, the control unit 60 performs an astigmatism test as an examination item for subjective measurement of the eye E to be examined. For example, the astigmatism test is a test for adjusting the cylinder power and the axis angle of astigmatism set as the initial values of the eye E to be examined to appropriate cylinder power and axis angle of astigmatism using a dot pattern target. The subject answers which of the two dot pattern targets is easier to see, or whether both appear equally clear, by operating the response lever 21 and the response button 22. For example, when the control unit 60 detects that a second operation signal has been input from the response button 22 and that the two dot pattern targets appear equally clear, it determines that the adjustment to the appropriate cylinder power and axis angle of astigmatism has been made.

[0064] Next, the control unit 60 performs a visual acuity test as an examination item for subjective measurement of the eye E to be examined. For example, the visual acuity test is a test for measuring the highest visual acuity value in a state where the eye E to be examined is corrected with an appropriate spherical power, an appropriate cylinder power, and an appropriate axis angle of astigmatism using a Landolt ring target. In the visual acuity test of this embodiment, the visual acuity value of the Landolt ring target is changed based on the first set number and the second set number set on the aforementioned setting screen 81. Hereinafter, a detailed description will be given along the flowchart shown in FIG. 6.

[0065] The eye E to be examined is in a corrected state with an appropriate spherical power, an appropriate cylindrical power, and an appropriate astigmatism axis angle through spherical examination and astigmatism examination (step P1). The control unit 60 causes the Landolt ring target to be displayed on the display 31 at a predetermined visual acuity value (step P2). As an example, the Landolt ring target is displayed at a visual acuity value of 1.0. Also, the control unit 60 generates an audio guide asking about the direction of the break of the Landolt ring target. The subject confirms the Landolt ring target and tilts the answer lever 21 if the direction of the break can be read, or presses the answer button 22 if the direction of the break cannot be read. For example, when the subject tilts the answer lever 21, the control unit 60 outputs a first operation signal indicating that there has been an input from the answer lever 21. Also, for example, when the subject presses the answer button 22, the control unit 60 outputs a second operation signal indicating that there has been an input from the answer button 22.

[0066] The control unit 60 detects the first operation signal from the answer lever 21 or the second operation signal from the answer button 22 (step P3). For example, when the control unit 60 obtains the first operation signal from the answer lever 21, it proceeds to detect the correctness of the subject's answer (the tilting direction of the answer lever 21) and the direction of the break of the Landolt ring target (step P4). Also, for example, when the control unit 60 obtains the second operation signal from the answer button 22, it proceeds to detect the number of operations of the answer button 22 (step P13). Note that step P13 will be described later.

[0067] First, the case where the first operation signal is obtained from the answer lever 21, that is, the case where it proceeds from step P3 to step P4 will be described. The control unit 60 detects the answer as a correct answer when the tilting direction of the answer lever 21 and the direction of the break of the Landolt ring target match. Also, the control unit 60 detects the answer as an incorrect answer when the tilting direction of the answer lever 21 and the direction of the break of the Landolt ring target do not match.

[0068] When the answer of the subject in step P4 is correct, the control unit 60 detects whether the number of correct answers has reached the first set number (step P5). Here, since the first set number is set to "3 / 5", if 3 or more out of 5 presentations of the Landolt ring target at a predetermined visual acuity value (for example, 1.0) are correct answers, it is considered that the subject's eye has that visual acuity. If the number of correct answers of the subject has reached the third time, the control unit 60 proceeds to detect whether the Landolt ring target presented to the subject's eye is at the highest visual acuity value (step P10). Also, if the number of correct answers of the subject has not reached the third time, the control unit 60 changes only the direction of the break while maintaining the visual acuity value of the Landolt ring target (step P6).

[0069] On the other hand, when the answer of the subject in step P4 is incorrect, the control unit 60 detects whether the number of incorrect answers has reached the number based on the first set number (step P7). As described above, since the first set number is set to "3 / 5", if 3 or more out of 5 presentations of the Landolt ring target at a predetermined visual acuity value are incorrect answers, it is considered that the subject's eye does not have that visual acuity. If the number of incorrect answers of the subject has reached the third time, the control unit 60 lowers the visual acuity value of the Landolt ring target by one step (for example, 0.9) and changes the direction of the break (step P8). Also, if the number of incorrect answers of the subject has not reached the third time, the control unit 60 changes only the direction of the break while maintaining the visual acuity value of the Landolt ring target (step P9).

[0070] Note that in the ophthalmic apparatus 100, the largest visual acuity value (for example, 2.0) of the Landolt ring target that can be presented to the subject's eye is set as the default highest visual acuity value. Therefore, in step P10, if the visual acuity value of the Landolt ring target presented to the subject's eye is the same as the highest visual acuity value, the control unit 60 acquires it by storing the highest visual acuity value in the memory 70 (step P12) and ends the visual acuity test. Also, in step P10, if the visual acuity value of the Landolt ring target presented to the subject's eye is different from the highest visual acuity value, the control unit 60 raises the visual acuity value of the Landolt ring target by one step (for example, 1.2) and changes the direction of the break (step P11).

[0071] In steps P6, P8, P9, and P11, when only the direction of the break of the Landolt ring chart or the visual acuity value and the direction of the break of the Landolt ring chart are changed, the control unit 60 returns to step P2 and displays the Landolt ring chart on the display 31 again.

[0072] Next, the case where a second operation signal is obtained from the answer button 22 in step P3 of FIG. 6 will be described. Conventionally, the second operation signal from the answer button 22 has been regarded as equivalent to a wrong answer and has proceeded to steps P4 and P7. If the number of correct answers or wrong answers does not reach the first set number, the visual acuity value of the Landolt ring chart has not been changed. However, with such a configuration, even though the subject admits that they "don't know" the direction of the break of the Landolt ring chart, it is necessary to repeat the input many times. Therefore, based on the number of operations of the answer button 22 by the subject and a preset second set number, the control unit 60 skips the remaining number of times of the first set number and controls to change the visual acuity value of the Landolt ring chart even if the number of correct answers or wrong answers has not reached the first set number.

[0073] When the control unit 60 obtains a second operation signal from the answer button 22 in step P3, it detects whether the number of operations has reached the second set number (step P13). Here, since the second set number is set to "1", if the second operation signal is detected even once, it is considered that the test eye cannot visually recognize the Landolt ring chart. If the number of operations of the answer button 22 has reached 1, the control unit 60 lowers the visual acuity value of the Landolt ring chart by one step (for example, to 0.9) and changes the direction of the break (step P14).

[0074] More specifically, for example, when the Landolt ring target is presented to the eye to be examined at a visual acuity of 1.0, if there is an input that cannot be recognized in the first presentation of the Landolt ring target, even if the number of correct answers is less than 3, the remaining 4 presentations of the visual acuity of 1.0 are skipped and the visual acuity is switched to 0.9. Also, for example, if the correct answers are given in the first and second presentations of the Landolt ring target and there is an input that cannot be recognized in the third presentation, even if the number of correct answers is less than 3, the remaining 2 presentations of the visual acuity of 1.0 are skipped and the visual acuity is switched to 0.9.

[0075] In addition, when the second set number is set to "1", since the number of operations always reaches 1 by operating the answer button 22, the detection process in step P13 may not be necessary. That is, it may be possible to proceed directly from step P3 to step P14. Of course, if the second set number is 2 or more, when the number of operations of the answer button 22 has not reached 2 or more, only the direction of the break may be changed while maintaining the visual acuity value of the Landolt ring target (step P15).

[0076] In steps P14 and P15, when the control unit 60 changes only the direction of the break of the Landolt ring target, or changes the visual acuity value and the direction of the break of the Landolt ring target, it returns to step P2 and displays the Landolt ring target on the display 31 again.

[0077] In this embodiment, in this way, until the number of correct answers (or the number of incorrect answers) of the subject reaches the first set number, the Landolt ring target is repeatedly presented to the eye to be examined at a predetermined visual acuity value. When the answer button 22 is operated, the remaining number of times of the first set number is skipped and the visual acuity value of the Landolt ring target is changed. When the control unit 60 acquires the maximum visual acuity value in step P12, it is considered that the visual acuity examination of the eye to be examined is completed, and the subjective measurement is terminated.

[0078] As described above, for example, the ophthalmic apparatus in the present embodiment includes a target presenting unit that presents an examination target to the eye to be examined, and an operation unit that the subject visually recognizes and operates the examination target, the operation unit including a response input unit that inputs a response to the examination target, and a non-visual recognition input unit that inputs that the examination target cannot be visually recognized. The apparatus further includes a change control unit that controls the target presenting unit to change the examination target to an examination target with a different visual acuity value when a first operation signal is input from the response input unit and a predetermined response reaches a first set number of times. When a second operation signal is input from the non-visual recognition input unit, the change control unit skips the remaining number of times of the first set number of times and controls the target presenting unit to change the examination target to an examination target with a different visual acuity value even if the predetermined response has not reached the first set number of times. As a result, for example, even when the subject determines that the examination target is "unknown", the visual acuity value of the examination target can be switched without repeating the input until the total number of incorrect answers is reached, so that the examination time can be shortened. In addition, the number of times the subject inputs an answer of "unknown" is reduced, and the operational and psychological burdens on the subject can be reduced.

[0079] Further, for example, the ophthalmic apparatus in the present embodiment includes a setting unit that sets a second set number of times for determining non-visual recognition of the examination target based on a second operation signal from the non-visual recognition input unit of the operation unit. The change control unit skips the remaining number of times of the first set number of times when the input of the second operation signal from the non-visual recognition input unit reaches the second set number of times. That is, for example, the examiner is configured to be able to set at least the second set number of times for the answer of "unknown" to an arbitrary number of times, and skips the remaining number of times for the answer of "incorrect answer" based on such an arbitrary number of times. As a result, for example, when the second set number of times is set to 1, the examination of the eye to be examined can be advanced more efficiently. Further, for example, when the second set number of times is set to 2 or more, the possibility that the subject accidentally inputs an answer of "unknown" is considered, and the examination of the eye to be examined can be advanced more accurately.

[0080] Further, for example, in the ophthalmic apparatus according to the present embodiment, the second set number is set to be smaller than the first set number. For this reason, when the subject visually recognizes the test target and inputs an answer such as a number or a direction, and when the subject inputs an answer without being able to visually recognize the test target, the method of proceeding with the ophthalmic examination is appropriately switched. As a result, the examination can be efficiently advanced and the time can be shortened.

[0081] Further, for example, in the ophthalmic apparatus according to the present embodiment, the answer input unit of the operation means is an answer input unit for inputting the direction of the test target. When a first operation signal is input from the answer input unit and a predetermined answer reaches the first set number, the change control means controls the target presenting means to change the test target to a test target with a different visual acuity value and a different direction. When a second operation signal is input from the non-visible input unit, even if the predetermined answer has not reached the first set number, the remaining number of times of the first set number is skipped, and the target presenting means is controlled to change the test target to a test target with a different visual acuity value and a different direction. Thereby, when the test target has a direction, the subject can input an answer by an intuitive operation. In addition, when the test target is switched, its visual acuity value and direction are changed, so that it becomes difficult to remember the direction of the test target.

[0082] <Modification example> In the present embodiment, the configuration in which the Landolt ring target is used as the test target for the astigmatism test has been described as an example, but the present invention is not limited to this. For example, the test target for the astigmatism test is not limited to the Landolt ring target, and a Snellen target or an E chart may be used.

[0083] In the present embodiment, the configuration in which the first set number for the number of correct answers or incorrect answers when the subject reads the Landolt ring target and the second set number for the non-visibility of the Landolt ring target by the subject are set by operating the setting screen 81 has been described as an example, but the present invention is not limited to this. For example, each setting may be reflected by reading the first set number and the second set number using an external storage device (for example, an SD card or a USB memory).

[0084] In this embodiment, the configuration in which the examiner sets the second set number to "1" is taken as an example for description, but the present invention is not limited thereto. For example, the examiner may set the second set number to a plurality of times. In this case, when the control unit 60 continuously obtains the second operation signal from the answer button 22, the remaining number of times of the first set number may be skipped, and the visual acuity value of the Landolt ring target may be switched. As an example, the second set number may be "2" or more, and when the second operation signal is input continuously twice, the remaining number of times of the first set number may be skipped, and the visual acuity value of the Landolt ring target may be switched.

[0085] In the ophthalmic apparatus according to this embodiment, in this way, the second set number for determining that the test target cannot be visually recognized is set to 2 or more, and when the second operation signal from the non-visual recognition input unit is continuous, the change control means may skip the remaining number of times of the first set number. For example, this can more accurately detect that the subject has determined that the test target cannot be visually recognized. That is, for example, it becomes easier to detect that the subject's operation of the non-visual recognition input unit because the test target cannot be visually recognized is not an erroneous operation. Therefore, the examination of the eye to be examined can be advanced with higher accuracy.

[0086] In this embodiment, the configuration in which the first set number and the second set number are used in combination in the visual acuity examination is taken as an example for description, but the present invention is not limited thereto. For example, the application of the second set number may be selectable in the visual acuity examination. For example, in this case, a mode in which the second set number is applied and a mode in which the second set number is not applied may be provided respectively. As an example, when switched to the mode in which the second set number is applied, the control according to the flowchart shown in FIG. 5 may be executed. Also, as an example, when switched to the mode in which the second set number is not applied, the control according to the conventional flowchart in which the second operation signal from the answer button 22 is regarded as equivalent to an incorrect answer may be executed.

[0087] In this embodiment, among the five presentations of the Landolt ring target to the eye to be examined at a predetermined visual acuity value, even if the input of "don't know" is made by operating the answer button 22 at any time, if the number of operations has reached the second set number, the configuration of decreasing the visual acuity value has been described as an example, but it is not limited to this. For example, depending on which presentation of the five presentations of the Landolt ring target the "don't know" input is made for, the control for changing the visual acuity value and the direction of the break of the Landolt ring target may be made different. For example, when "don't know" is input for the first presentation of the Landolt ring target, the control along the flowchart of FIG. 6 may be executed. Also, for example, when "don't know" is input for the second and subsequent presentations of the Landolt ring target, the second operation signal of "don't know" from the answer button 22 may be regarded as equivalent to a wrong answer, and subsequent control may be executed. Note that especially when the second set number is "2" or more, such switching of control can suppress the inspection time from becoming long.

[0088] In this embodiment, in the state where the eye to be examined is corrected with an appropriate correction degree obtained by spherical aberration inspection and astigmatism inspection, the configuration of appropriately changing the visual acuity value of the Landolt ring target and obtaining the maximum visual acuity value has been described as an example, but it is not limited to this. For example, it may be configured to further adjust the correction degree of the eye to be examined to obtain the value of the correction degree of the plus degree (that is, the complete correction value) at which the maximum visual acuity of the eye to be examined is obtained. For example, in this case, even if the number of correct answers or wrong answers of the subject has not reached the first set number, the control unit 60 may skip the remaining number of times of the first set number based on the input of the second operation signal from the answer button 22 and correct the eye to be examined with different correction degrees. As an example, the control unit 60 may increase the spherical degree by one step based on the input of "don't know" after increasing the visual acuity value of the Landolt ring target by one step. Also, as an example, the control unit 60 may decrease the spherical degree by one step based on the input of "don't know" after decreasing the visual acuity value of the Landolt ring target by one step.

[0089] The ophthalmic apparatus in this embodiment may be provided with a correction means for changing the optical characteristics of the target light beam emitted from the target presenting means. When the test eye is corrected at the first correction power by the correction means and a first operation signal is input from the response input unit, and when a predetermined response reaches the first set number of times, the change control means controls the correction means to change the first correction power to a different second correction power. When a second operation signal is input from the non-visible input unit, even if the predetermined response has not reached the first set number of times, the remaining number of times of the first set number of times is skipped, and the correction means can be controlled to change the first correction power to a different second correction power. For example, thereby, even when obtaining the complete correction value or prescription value of the test eye, when the subject determines that the test target is "unknown", the correction power can be appropriately switched without repeating the input until the total number of incorrect answers is reached. Therefore, the examination time of the test eye can be shortened.

Explanation of Signs

[0090] 1 Housing 2 Presentation Window 3 Speaker 10 Examiner Controller 20 Subject Controller 30 Light Projection Optical System 40 Ocular Refractive Power Measurement Unit 43 Inspection Window 60 Control Unit 100 Subjective Ophthalmic Apparatus

Claims

1. An ophthalmic apparatus for examining an eye to be examined, a target presenting means for presenting an examination target to the eye to be examined, an operation means for the subject to visually recognize and operate the examination target, the operation means having a response input unit for inputting a response to the examination target and a non-visual recognition input unit for inputting that the examination target cannot be visually recognized, a change control means for controlling the target presenting means to change the examination target to an examination target with a different visual acuity value when a first operation signal is input from the response input unit and a predetermined response reaches a first set number of times, comprising, when a second operation signal is input from the non-visual recognition input unit, the change control means skips the remaining number of times of the first set number even if the predetermined response has not reached the first set number of times, and controls the target presenting means to change the examination target to an examination target with a different visual acuity value. The ophthalmic apparatus is characterized by this.

2. In the ophthalmic apparatus according to Claim 1, provided with setting means for setting a second set number of times for determining non-visual recognition of the examination target based on the second operation signal from the non-visual recognition input unit, the change control means is characterized by skipping the remaining number of times of the first set number when the input of the second operation signal from the non-visual recognition input unit reaches the second set number of times. The ophthalmic apparatus is characterized by this.

3. In the ophthalmic apparatus according to Claim 2, the ophthalmic apparatus is characterized in that the second set number is a number smaller than the first set number.

4. In the ophthalmic apparatus according to Claim 2 or 3, the second set number is 2 or more, the change control means is characterized by skipping the remaining number of times of the first set number when the second operation signal from the non-visual recognition input unit is continuous. The ophthalmic apparatus is characterized by this.

5. In the ophthalmic apparatus according to any one of Claims 1 to 4, The response input unit of the operation means is a response input unit for inputting the direction of the test target, and the change control means when the first operation signal is input from the response input unit and the predetermined response reaches the first set number of times, controls the target presenting means to change the test target to a test target with a different visual acuity value and in a different direction, when the second operation signal is input from the non-visible input unit, even if the predetermined response has not reached the first set number of times, skips the remaining number of times of the first set number of times and controls the target presenting means to change the test target to a test target with a different visual acuity value and in a different direction An ophthalmic apparatus characterized by the above.

6. In the ophthalmic apparatus according to any one of claims 1 to 5, It is provided with correction means for changing the optical characteristics of the target light beam emitted from the target presenting means, the change control means in a state where the eye to be examined is corrected by the correction means with a first correction degree, when the first operation signal is input from the response input unit and the predetermined response reaches the first set number of times, controls the correction means to change the first correction degree to a different second correction degree, when the second operation signal is input from the non-visible input unit, even if the predetermined response has not reached the first set number of times, skips the remaining number of times of the first set number of times and controls the correction means to change the first correction degree to a different second correction degree An ophthalmic apparatus characterized by the above.

7. A target presenting means for presenting a test target to the eye to be examined, An operation means for the subject to visually recognize and operate the test target, the operation means having a response input unit for inputting a response to the test target and a non-visible input unit for inputting that the test target cannot be visually recognized, having An ophthalmic program used in an ophthalmic apparatus for examining the eye to be examined, When the ophthalmic examination program is executed by a processor, a first operation signal is input from the response input unit, and when a predetermined response reaches a first set number of times, a change control step is executed by the ophthalmic apparatus to control the target presenting means to change the examination target to an examination target with a different visual acuity value. The change control step is characterized in that, when a second operation signal is input from the non-visible input unit, even if the predetermined response has not reached the first set number of times, the remaining number of times of the first set number of times is skipped, and the target presenting means is controlled to change the examination target to an examination target with a different visual acuity value. An ophthalmic examination program.

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