JP2005046245A - Ophthalmologic measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ophthalmologic measuring device with a high measuring precision suppressing the influence by outer disturbing light. <P>SOLUTION: The ophthalmologic measuring device is constituted as the following. The projection light optical axis L1 of a projection optical system 4 and the reception light optical axis L2 of a reception light optical system 5 make a substantially right angle at the peak of the site S to be measured. The reception light optical axis L2 is set between the optical axis L4 of a cornea reflection light reflecting on the cornea when a projection light enter an eye to be tested and the optical axis L3 of an IOL reflection light which is the reflecting light of the projection light on an IOL 2 with the proviso that the IOL 2 is inserted into the eye to be tested so as not to intersect with any of the optical axis L3, L4. The distances between the reception light optical axis L2, the optical axis L4 of the cornea reflection light, and the optical axis L3 of the IOL reflection light is set so that the reception optical system 5 does not receive the cornea reflection light and the IOL reflection light. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention projects light into the eye to be examined, and receives the scattered light of the measurement target portion in the eye to be examined by the projected light, for example, biological characteristics such as the number of cells floating in the anterior chamber and protein concentration The present invention relates to an ophthalmologic measurement apparatus that measures the above.
[0002]
[Prior art]
Conventionally, flare meters and flare cell meters are known as ophthalmic measuring apparatuses. These ophthalmologic measuring apparatuses are capable of measuring the number of cells floating in the anterior chamber of the eye to be examined and the protein concentration (flare concentration).
[0003]
Such an ophthalmologic measuring apparatus projects light into the eye to be examined from an oblique direction with respect to the eyeball optical axis of the eye to be examined, and receives scattered light from the oblique direction on the opposite side of the eyeball optical axis from the projected light. (See Patent Documents 1 to 4).
[0004]
In the above method, in order to suitably measure scattered light, the light receiving optical system receives light from the measurement target scattered light (measurement target light) from a direction substantially perpendicular to the projection light optical axis of the projection optical system. The optical axis is arranged, and the projected optical axis and the received optical axis are substantially perpendicular to the measurement target portion in the eye to be examined.
[0005]
Then, since the projection light optical axis and the light reception optical axis are substantially perpendicular to each other, it is considered to be able to easily arrange both the projection light optical axis and the light reception optical axis from the ophthalmic measurement device facing the eye to be examined. It was done. In a conventional ophthalmic measurement apparatus, an angle between the projection light optical axis and the light reception optical axis is equally divided by an axis that passes through the measurement target portion in the subject eye parallel to the eyeball optical axis, that is, the projection light optical axis and the eyeball. A setting has been made such that the projection angle between the axis passing through the measurement target portion in the eye to be examined parallel to the optical axis is approximately 45 ° (see Patent Document 2).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 3-264044
[Patent Document 2]
JP-A-6-217939
[Patent Document 3]
Japanese Patent Laid-Open No. 7-178052
[Patent Document 4]
Japanese Patent Laid-Open No. 9-84763
[0007]
[Problems to be solved by the invention]
However, in recent years, an artificial lens (intraocular lens: IOL) is sometimes inserted into an eye to be examined in a cataract patient.
[0008]
Since the IOL has a high refractive index, the projection light of the conventional ophthalmic measurement apparatus reaches the IOL surface and is reflected as IOL reflected light (artificial crystalline lens reflected light) on the IOL surface. As shown in FIG. 5, the conventional ophthalmic measurement apparatus has a projection angle of about 45 ° with respect to the axis L0 ′ of the projection light optical axis L1, so when measuring a subject using an IOL. The IOL reflected light optical axis L3 of the IOL reflected light that has passed through the measurement target portion S and reflected from the IOL surface is aligned close to the light receiving optical axis L2.
[0009]
Then, the light receiving element of the light receiving optical system that should receive the scattered light of the measurement target portion S in the eye to be examined along the light receiving optical axis L2 also receives the IOL reflected light. Since the IOL reflected light has a strong light intensity, if the light receiving element of the light receiving optical system receives the IOL reflected light, as shown in FIG. 6, the light intensity of the saturated light is received and cannot be measured. Damage to the device will occur.
[0010]
For this reason, as shown in FIG. 7, the projection angle with respect to the axis L0 ′ of the projection light optical axis L1 is set to 30 ° so that the subject using the IOL can perform measurement well. It was considered that the projection light was removed together with the corneal reflection light (optical axis L4) reflected by the cornea when entering the eye to be examined. In this case, the angle formed by both the IOL reflected light optical axis L3 and the corneal reflected light optical axis L4 with the eyeball optical axis L0 was set small and could be separated from the light receiving optical axis L2.
[0011]
However, even in this case, scattered light from the cornea when the IOL reflected light goes out of the eye to be examined (IOL reflected scattered light (optical axis L5)) enters the light receiving element of the light receiving optical system. The light intensity of the IOL reflected / scattered light approximates the light intensity when the measurement target portion has a large amount of scattering. Therefore, as shown in FIG. 8, the measurement result produces a ghost image G even if there is little scattering of the measurement target portion S, and the apparent flare amount is made larger than the actual flare amount, resulting in a measurement error. It was.
[0012]
The present invention has been made in view of the above prior art, and an object of the present invention is to provide an ophthalmic measurement apparatus with high measurement accuracy in which the influence of ambient light is suppressed.
[0013]
[Means for Solving the Problems]
In the present invention, there is a problem that the scattered light (IOL reflected / scattered light) from the cornea when the artificial lens reflected light (IOL reflected light) goes out of the eye to be examined enters the light receiving element of the light receiving optical system. A ghost image of scattered light (IOL reflected and scattered light (optical axis L5)) while passing through the cornea exists near the light receiving optical axis and has a scattering region R on the cornea when the artificial lens reflected light goes out of the eye to be examined. It was noticed that this occurs because it covers the measurement region on the light receiving optical axis (see FIG. 7).
[0014]
Then, it is considered that the scattering region R in the cornea when the artificial lens reflected light goes out of the eye to be examined can be separated from the light receiving optical axis L2 of the light receiving optical system, and this determines the projection angle of the projection light optical axis L1 of the projection optical system. Recalling that it can be achieved by extending beyond 45 degrees.
[0015]
However, if the projection angle of the projection light optical axis L1 is greatly widened, this time, the reflected light (corneal reflection light (optical axis L4)) of the projection light generated in all the examinee's eyes when entering the test eye. )) Enters the light-receiving element of the light-receiving optical system, and the cornea-reflected light causes a measurement failure problem of the same type as that of the artificial lens-reflected light and the scattered light in the cornea (IOL-reflected scattered light). Can not be expanded too much.
[0016]
Therefore, the optical axis of the artificial lens reflected light that determines the extending direction of the artificial lens reflected light and the scattering position of the artificial lens reflected light in the cornea when going out of the eye to be examined, and the projection light at the cornea when entering the eye to be examined The present invention has been embodied by expanding the projection angle only within a range in which a light receiving optical axis that does not intersect any optical axis and is not close to any optical axis is set between the optical axis of the reflected light.
[0017]
A specific ophthalmologic measurement apparatus according to the present invention is an ophthalmic measurement apparatus that measures biological characteristics in a subject eye by projecting light into the subject eye and receiving scattered light. A projection optical system that projects the projection light obliquely with respect to the optical axis of the eyeball; and a light receiving optical system that receives the scattered light scattered by the measurement unit in the eye to be examined. The projection light optical axis of the optical system and the light reception optical axis of the light receiving optical system form a substantially right angle with the measurement unit at the apex, and the light reception optical axis is reflected by the cornea reflected by the cornea when the projection light enters the eye to be examined. Between the optical axis and the optical axis of the artificial lens reflected light reflected by the artificial crystalline lens when the projected light is assumed to be inserted into the eye to be examined without intersecting any optical axis. The light receiving optical axis, the optical axis of the cornea reflected light, and the artificial crystalline lens reflection Each between the optical axis, and characterized in that said not receiving the corneal reflected light and the artificial lens reflected light to the light receiving optical system distance.
[0018]
The light receiving optical system includes a light receiving element that receives the scattered light, and a light receiving optical path along the light receiving optical axis to the light receiving element, and has a predetermined size at a position optically conjugate with the measurement unit. It is preferable that the light shielding member guides only the scattered light transmitted through the opening to the light receiving element.
[0019]
In this configuration, the light receiving optical system does not receive any of the corneal reflected light, artificial lens reflected light, and artificial lens reflected light scattered by the cornea when going out of the subject's eye, so that the target using an artificial lens (IOL) is used. For the examiner, the influence of disturbance light is suppressed, and since there is no ghost image due to disturbance light, no measurement error occurs and measurement can be performed with high measurement accuracy. Even for subjects who do not use an artificial lens, the artificial lens has a high refractive index, but the normal lens has a low refractive index, and it is difficult for reflection to occur in the lens, thus suppressing the effects of ambient light. And can be measured well.
[0020]
Therefore, in the present invention, uniform measurement can be performed uniformly with high accuracy for all subjects without limiting the subjects to be measured.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.
[0022]
"overall structure"
FIG. 1 is a schematic configuration diagram of a laser flare meter (hereinafter referred to as LFM) according to the present embodiment. In the present embodiment, the description will be given by taking LFM as an example of an ophthalmic measurement apparatus. Note that the LFM of the present embodiment not only measures biological properties such as the number of cells (cells) floating in the normal anterior chamber of the eye to be examined and protein concentration (flare concentration), but also turbidity of the eye lens to be examined. The degree of biological properties can also be measured.
[0023]
In FIG. 1, an eye 1 to be examined, which is an eyeball of a subject, is shown, and an LFM measurement unit 3 is arranged facing the eye 1 to be examined. In the eye 1 to be examined, the contents of the turbid lens are sucked out and an artificial lens (IOL) 2 is inserted and operated.
[0024]
The measuring unit 3 of the LFM generally includes a projection optical system 4 along the projection light optical axis L1, a light reception optical system 5 along the light reception optical axis L2, and an XY along the eyeball optical axis L0 where the eye 1 to be examined stares. The direction alignment part 6 and the Z direction alignment part 7 along the incident light optical axis L6 and the reflected light optical axis L7 are provided.
[0025]
The LFM measuring unit 3 includes one display unit 8 for performing various displays at one place, an analysis unit 9 for performing various data analysis, and a switcher 10 for switching data displayed on the display unit 8; It has.
[0026]
In the present embodiment, all the components mounted on the measurement unit 3 of the LFM are moved by the alignment of the measurement unit 3.
[0027]
Here, the eyeball optical axis L0 extends straight from the corneal apex of the subject eye 1 to the front. The eyeball optical axis L0 is shifted without overlapping the measurement target portion S that is the intersection of the projection light optical axis L1 and the light receiving optical axis L2. Note that the eyeball optical axis L0 is normally one, but for the sake of explanation, FIG. 1 shows each optical path from each light source.
[0028]
Further, as shown in FIG. 2, the incident light optical axis L6 and the reflected light optical axis L7 for alignment in the Z direction are reflected at the corneal apex of the eye 1 to be examined, which intersects the eyeball optical axis L0, and with respect to the eyeball optical axis L0. It has a symmetric 30 ° incident angle and reflection angle.
[0029]
On the other hand, the projection light optical axis L1 and the light reception optical axis L2 intersect at a predetermined position in the eye 1 to be examined, that is, in the anterior chamber of the eye 1 to form an intersection of both optical axes L1 and L2. The intersection position indicates the measurement target portion S. Thereby, the light receiving optical system 5 can receive the scattered light on the light receiving optical axis L <b> 2 in which the projection light from the projection optical system 4 is scattered by the measurement target portion S in the anterior chamber of the eye to be examined.
[0030]
As shown in FIG. 2, the angle at the intersection of the projection optical axis L1 and the light receiving optical axis L2 is set to be a right angle so that the scattered light of the measurement target can be measured favorably. In other words, the light receiving optical axis L2 of the light receiving optical system 5 is disposed so as to receive the scattered light to be measured from the direction substantially perpendicular to the projection light optical axis L1 of the projection optical system 4, and the projection light optical axis L1 and the light receiving optical axis L2 are perpendicular to the vertex of the measurement target portion S in the eye 1 to be examined.
[0031]
The projection light optical axis L1 extends into the eye to be examined with a projection angle of 50 ° with the axis L0 ′ passing through the measurement target portion S parallel to the eyeball optical axis L0. Since the projection light optical axis L1 and the light reception optical axis L2 form a right angle, the light reception optical axis L2 has a light reception angle between the axis L0 ′ passing through the measurement target portion S parallel to the eyeball optical axis L0. It extends from the eye 1 to be examined.
[0032]
“Relationship between optical position of projection optical axis L1 and light receiving optical axis L2”
As described above, the projection light optical axis L1 is disposed with a projection angle of 50 ° between the projection light optical axis L1 and the axis L0 ′ passing through the measurement target portion S parallel to the eyeball optical axis L0. The reason for setting the projection angle to 50 ° is that the subject using the IOL 2 can perform measurement well, and the measurement accuracy is improved by suppressing the influence of ambient light.
[0033]
Specifically, in recent years, IOL 2 may be inserted into the eye 1 to be examined of a cataract patient to restore visual acuity. Since the IOL2 has a high refractive index, as shown in FIG. 3, IOL reflected light (artificial crystalline lens reflected light) that passes through the measurement target portion S in the eye 1 and is reflected by the surface of the IOL2 is generated. If the IOL reflected light is received, the photoelectric detector 15 of the light receiving optical system 5 receives the saturated light amount and becomes impossible to measure (see FIG. 6).
[0034]
Further, when scattered light (IOL reflected / scattered light) from the cornea when the IOL reflected light goes out of the subject's eye enters the photoelectric detector 15 of the light receiving optical system 5, the IOL reflected / scattered light is scattered by the measurement target portion S. In order to approximate the light intensity in this case, a ghost image G is generated even if the scattering of the measurement target portion S is small, and the apparent flare amount is increased, resulting in a measurement error (see FIG. 8).
[0035]
Further, when the reflected light (corneal reflected light) of the projection light generated in the subject's eye 1 of all subjects enters the photoelectric detector 15 of the light receiving optical system 5 when entering the subject's eye, IOL reflected light or It causes the same measurement failure problem as the scattered light (IOL reflected scattered light) in the cornea.
[0036]
Therefore, as shown in FIG. 3, the IOL reflected light optical axis L3 that determines the extending direction of the IOL reflected light and determines the scattering position of the IOL reflected light in the cornea when going out of the eye to be examined, and when the projection light enters the eye to be examined As a projection angle of the projection light optical axis L1 limited to a range in which the light reception optical axis L2 that does not intersect with any of the optical axes L3 and L4 and is not close to the cornea reflected light optical axis L4 in the cornea In this embodiment, 50 ° is set. As an invention, the projection angle is not limited to 50 ° as long as the above conditions can be satisfied. A range of 50 ° to 53 ° is preferred.
[0037]
By setting the projection angle of the projection light optical axis L1 in this way, the light reception optical axis L2 is the optical axis L3 of the IOL reflected light in which the projection light is reflected by the IOL2 in the eye 1 to be examined, and the projection light is the eye to be examined. The optical axis L4 of the corneal reflected light reflected by the cornea at the time of entry is set without crossing any of the optical axes L3 and L4, and between the light receiving optical axis L2 and the IOL reflected light optical axis L3 and light receiving. The optical axis L2 and the corneal reflected light optical axis L4 are separated by a distance at which the light receiving optical system 5 does not receive the corneal reflected light and the IOL reflected light. The IOL reflected light optical axis L3 and the corneal reflected light optical axis L4 are separated away from the light receiving optical axis L2 toward the eye 1 to be examined.
[0038]
For this reason, since the corneal reflected light, the IOL reflected light, and the scattered light of the IOL reflected light at the cornea when going out of the subject's eye are not received by the light receiving optical system 5, disturbance to the subject using the IOL 2 Since the influence of light is suppressed and there is no ghost image due to disturbance light, no measurement error occurs, and measurement can be performed with high measurement accuracy. Also, for subjects not using IOL2, IOL2 has a high refractive index, but a normal crystalline lens has a low refractive index, and it is difficult for reflection of projection light from the crystalline lens to occur. Suppress and measure well.
[0039]
Therefore, in the LFM of the present embodiment, the disturbance light is applied to all subjects without limiting the subject to be measured to either a subject using IOL or a subject not using IOL. It is possible to perform uniform measurement with high accuracy uniformly while suppressing the influence of.
[0040]
"Specific explanation of each component"
(Projection optical system)
The projection optical system 4 of the LFM measuring unit 3 will be described. In the projection optical system 4, laser light as projection light emitted from a laser light source 11 such as a visible laser diode passes through a condenser lens 12 along the projection optical axis L 1 and the anterior chamber of the subject's eye 1. Projected into.
[0041]
The condenser lens 12 is driven in a direction perpendicular to the projection light optical axis L1 and the paper surface by a driving unit (not shown), and scans the laser light in a one-dimensional manner.
[0042]
As described above, since the scanning of the laser beam is performed by simply moving the condensing lens 12, the scanning can be realized with a simple configuration, and the cost can be reduced. In addition, when scanning laser light in multiple directions to measure the number of cells (cells) floating in the anterior chamber as a laser flare cell meter, it is only necessary to add another movable condensing lens, Improvement of the device is also simple.
[0043]
(Reception optical system)
Next, the light receiving optical system 5 will be described. The light receiving optical system 5 is a light receiving element that scatters the scattered light in the measurement target portion S in the eye 1 to be examined by the laser light from the laser light source 11 through the lens 13 and the light receiving mask 14 as a light shielding member along the light receiving optical axis L2. Detection is performed by a photoelectric detector 15 such as a photomultiplier tube.
[0044]
The lens 13 is a spherical lens in which the optical axis of the lens 13 is inclined with respect to the light receiving optical axis L2. The lens 13 is used to remove large astigmatism that occurs when an image of scattered light that has passed through the cornea that generates large aberration is formed. Thereby, aberrations can be easily removed, and measurement accuracy can be improved.
[0045]
The light receiving mask 14 is used to limit the field of view in the direction of the light receiving optical axis L2 and to define the measurement range. The light receiving mask 14 is provided in a light receiving optical path along the light receiving optical axis L2 up to the photoelectric detector 15 and has an opening of a predetermined size at a position optically conjugate with the measurement target portion S. The light receiving mask 14 guides only the scattered light transmitted through the opening to the photoelectric detector 15. The IOL reflected light optical axis L3 and the corneal reflected light optical axis L4 do not overlap in the optical path range limited by the opening of the light receiving mask 14 due to the optical axis arrangement relationship of FIG. 3, but the IOL reflected light, the IOL reflected scattered light, the cornea The reflected light is blocked by the light receiving mask 14.
[0046]
The photoelectric detector 15 receives only the scattered light limited by the light receiving mask 14, converts the received light intensity into an electrical signal, and outputs it as an output signal.
[0047]
The scattered light in the subject eye 1 is, for example, scattered light from proteins present in the anterior chamber of the subject eye 1, scattered light from floating cells (cells) in the anterior chamber, Or scattered light from the crystalline lens of the optometer 1.
[0048]
In the light receiving optical system 5, a shutter 16 is disposed between the lens 13 and the light receiving mask 14 to block scattered light when not measuring. The shutter 16 is closed to prevent the photoelectric detector 15 from receiving scattered light or external disturbance light when not measuring.
[0049]
Then, the output signal from the photoelectric detector 15 that has received the scattered light in the light receiving optical system 5 is supplied to the analysis unit 9. The analysis unit 9 calculates biological characteristics such as protein concentration from the output signal of the scattered light, and displays the measurement result on the display unit 8 based on the calculation.
[0050]
For example, for the calculation of the biological characteristics, the analysis unit 9 analyzes the output signal digitized using the photon counting method. In the case of this photon counting method, a photocount value is used as the received light intensity. Each photocount value obtained by scanning with laser light is stored in a memory in the analysis unit 9 in time series.
[0051]
In addition, the light receiving optical system 5 includes a half mirror 17 for branching the optical path, a CCD camera 18 as second imaging means on the optical path branched by the half mirror 17, and a lens provided in front of the CCD camera 18. 19 are arranged.
[0052]
The half mirror 17 branches scattered light from the light receiving optical axis L 2, the scattered light branched by the half mirror 17 is collected by the lens 19, and the collected image is received by the CCD camera 18.
[0053]
As a result, the CCD camera 18 can photograph the appearance of the measurement portion of the eye 1 from the light receiving optical system 5. Then, by displaying the output of the CCD camera 18 on the display unit 8, the examiner can enlarge and display the appearance of the measurement part appearance of the eye 1 to be examined on the display unit 8.
[0054]
(XY direction alignment part)
Next, the XY direction alignment unit 6 will be described. The XY-direction alignment unit 6 is an optical configuration that is disposed along the eyeball optical axis L0. In the XY direction alignment unit 6, the illumination light from the illumination light source 20, which is an infrared LED, passes through the lens 21, the half mirror 22, and the lens 23 along the eyeball optical axis L 0, in particular, Irradiates the apex of the cornea.
[0055]
In addition, illumination light from the internal fixation lamp 24, which is a green LED for the subject to stare at one point, passes through the half mirror 25, the half mirror 22, and the lens 23 along the eyeball optical axis L0. The optometry 1 is irradiated.
[0056]
When the illumination light from the illumination light source 20 reaches the corneal surface of the eye 1 to be examined, the anterior segment image of the eye 1 to be examined, which is a virtual image of the bright spot of corneal reflection, is reflected. The reflected anterior segment image of the subject eye 1 travels straight through the lens 23, the half mirror 22, and the half mirror 25 on the eyeball optical axis L 0, and then serves as a first imaging unit that constitutes a light receiving unit with the lens 26. The image is formed on the light receiving surface of the CCD camera 27.
[0057]
In addition, an infrared filter 28 that passes only the wavelength of the infrared LED of the illumination light source 20 is disposed in front of the light receiving surface of the CCD camera 27 in order to reduce the influence of disturbance light.
[0058]
Further, illumination light from the light source 29 that is an infrared LED is also received by the CCD camera 27 on the screen displaying the anterior segment image. The illumination light from the light source 29 displays a circle that glows in a ring shape. The circle indicates the position of the measurement unit 3 of the LFM, and the position determination point where the alignment matching of the measurement unit 3 of the LFM is taken is determined by aligning the anterior segment image in the circle.
[0059]
The illumination light from the light source 29 is received by the CCD camera 27 via the circle display mask 30, the lens 31, the half mirror 25, and the lens 26. Since the light source 29 is also an infrared LED, the circle display from the light source 29 is received by the CCD camera 27 without being excluded by the infrared filter 28.
[0060]
The CCD camera 27 is connected to the display unit 8 via the switch 10. The anterior ocular segment image and circle of the subject eye 1 received by the CCD camera 27 are displayed on the display screen of the display unit 8.
[0061]
(Z direction alignment part)
Next, the Z direction alignment part 7 is demonstrated. In the Z-direction alignment unit 7, illumination light from a light source 32 that is an LED having a wavelength different from that of the illumination light source 20 is irradiated to the cornea of the eye 1 through the lens 33 along the incident light optical axis L 6.
[0062]
Then, the reflected light that becomes a virtual image of the bright spot on the surface of the cornea is detected by the two-divided sensor 35 such as a two-divided photodiode on the reflected light optical axis L7 through the lens 34.
[0063]
The incident light optical axis L6 and the reflected light optical axis L7 are set to have a line-symmetric inclination with respect to the eyeball optical axis L0 with the apex angle of the cornea. In the present embodiment, the incident light optical axis L6 and the reflected light optical axis L7 are each 30 ° with respect to the eyeball optical axis L0.
[0064]
The two-divided sensor 35 is for determining the distance (Z-axis direction) between the corneal apex of the eye 1 to be examined and the LFM measuring unit 3 from the light quantity ratio of the corneal reflection incident on the light receiving surface. In this two-divided sensor 35, two alignment completion points are set as standard. A plurality of alignment completion points can also be provided.
[0065]
In the present embodiment, the measurement target can be set to the anterior chamber position and the crystalline lens position of the eye 1 to be measured by the output of the two-divided sensor 35. For example, when the intensity ratio of the two-divided sensor 35 is 10:10, it is set as the measurement target part of the protein mass (flare) in the anterior chamber, and when the intensity ratio is 5:15, it is set as the measurement target part of the turbidity of the lens To do. In the present embodiment, a case is described in which measurement is performed by adjusting the position in the anterior chamber position.
[0066]
Here, all adjustments of the alignment of the LFM measurement unit 3 in the XYZ directions may be performed manually by the examiner's joystick. Alternatively, control may be performed so that all alignment adjustments are automatically performed. Further, the coarse movement may be performed in the XY directions by an examiner's operation of a joystick, and the fine movement may be automatically performed.
[0067]
(Display section)
The display unit 8 includes (1) a measurement result from the analysis unit 9 at the time of measurement, (2) appearance of a measurement part appearance of the eye 1 to be examined from the CCD camera 18 at the time of alignment adjustment, and (3) an object to be measured from the CCD camera 27. An anterior segment image and a circle of the optometry 1 are displayed. That is, the three displays (1) to (3) are switched and displayed. The display is switched by the switch 10 under the control of the analysis unit 9.
[0068]
Since only one display unit 8 is provided and the display is switched as described above, the examiner only needs to observe the screen of the display unit 8 at all times, and the examiner is different between the alignment adjustment and the measurement. There is no need to move the viewpoint to the part, improving the operability for the examiner.
[0069]
(Analysis Department)
The analysis unit 9 is a part that performs information analysis and operation control. That is, processing such as analysis work and operation work is executed using a hardware configuration according to a program stored in advance. As a hardware configuration, for example, a general computer configuration can be adopted.
[0070]
The analysis unit 9 analyzes the output signal on the one hand, and controls the switch 10 in accordance with the input of the examiner on the other hand to switch the display target to be displayed on the display unit 8 and also displays the joystick of the examiner and the like. The drive motor is driven according to the input operation.
[0071]
"Measurement"
Next, measurement using LFM will be described. Measurement is divided into alignment adjustment before the start of measurement and execution of actual measurement.
[0072]
"Adjusting the alignment"
First, the case where alignment adjustment is performed on the eye 1 to be examined will be described.
[0073]
The alignment is adjusted by adjusting the XY direction alignment by the XY direction alignment unit 6 and the Z direction alignment by the Z direction alignment unit 7 before adjusting the XY direction alignment.
[0074]
(Adjustment of XY direction alignment)
The adjustment of the XY direction alignment performed first will be described. The XY direction alignment is adjusted using the XY direction alignment unit 6.
[0075]
The XY direction alignment is adjusted by using an anterior ocular segment image and a circle of the subject eye 1 received by the CCD camera 27 displayed on the display unit 8, and an anterior corneal eye image showing a virtual image of the corneal reflection of the subject eye. It is performed by moving in the XY direction perpendicular to the axis L0 and aligning the position of the LFM measuring unit 3 within a defined circle.
[0076]
First, the illumination light source 20 is turned on, and the reflected light reflected from the cornea surface of the eye 1 to be examined of the illumination light source 20 is received by the CCD camera 27, and the anterior segment image of the subject eye 1 is displayed on the display screen of the display unit 8. Let Similarly, the circle in which the position of the measurement unit 3 of the LFM is received is also received and displayed on the display screen of the display unit 8.
[0077]
Then, for example, the examiner moves the LFM measurement unit 3 with a joystick while looking at the anterior ocular segment image and the circle on the display unit 8 so as to align the anterior ocular segment image within the circle.
[0078]
In the present embodiment, the X direction in the XY direction is set to the horizontal (left and right) direction of the LFM, and the Y direction is set to the vertical (up and down) direction of the LFM.
[0079]
(Adjustment of alignment in Z direction)
When the alignment in the XY directions is completed, the alignment in the Z direction is next adjusted.
[0080]
Adjustment of alignment in the Z direction is performed using the Z direction alignment unit 7.
[0081]
In the adjustment of the Z-direction alignment, the output value of the two-divided sensor 35, which is the adjustment completion, is set in advance, so that the LFM is measured in the Z direction, that is, in the perspective direction with respect to the eye 1 to be measured. The measurement unit 3 is moved back and forth.
[0082]
The examiner performs an operation according to a forward instruction, a backward instruction, or the like displayed on the display unit 8 with a joystick while looking at the display unit 8.
[0083]
When the measurement unit 3 of the LFM is moved in the perspective direction with respect to the subject eye 1 and the output value of the two-divided sensor 35 reaches a preset value, the position is determined, for example, by displaying a buzzer sound or a determination completion display. Inform the person that the alignment is complete.
[0084]
“Perform Measurement”
After the alignment is completed by the above operation, the measurement is actually started.
[0085]
(Check for disturbance)
First, the brightness around the device is checked in consideration of the influence of ambient light. The brightness around the apparatus is checked by opening the shutter 16 of the light receiving optical system 5 without irradiating laser light from the projection optical system 4 and the amount of disturbance light received by the photoelectric detector 15 exceeds a predetermined amount that can be measured. Judge whether or not.
[0086]
(Main measurement)
If the amount of disturbance light is within a predetermined amount that can be measured, the laser light source 11 of the projection optical system 4 starts to irradiate and starts measurement.
[0087]
The laser beam irradiation start point is set at an upper position exceeding the measurement scanning width of the eye 1 to be examined by scanning of the condensing lens 12, and the condensing lens 12 finely performs one-dimensional scanning, The laser beam is scanned across the measurement scanning width from above to below the eye 1 to be examined.
[0088]
Therefore, in the light receiving optical system 5, the scattered light in the subject eye 1 of the irradiated laser light is irradiated from the laser light irradiation start position (above the subject eye) across the measurement scanning width to the irradiation end position (below the subject eye). Detect in the range of.
[0089]
(Intensity of scattered light)
The intensity of the scattered light detected by the photoelectric detector 15 is as shown in the table of FIG. Here, in the table of FIG. 4, it is shown from T1 when the shutter 16 is first opened, T2 when the laser beam irradiation starts, T3 when measurement starts, T4 when measurement ends, and laser beam irradiation. The intensity of the scattered light is shown in a time series from T5 when completed to T6 when the shutter 16 is closed.
[0090]
In FIG. 4, regions A and E are light intensities detected by the photoelectric detector 15 due to disturbance light that is not irradiated with laser light. Regions B and D are light intensities (background values) due to disturbance light that has been irradiated with laser light but has not yet been scanned in the measurement target portion. Region C is the light intensity during measurement (measurement scanning width) in which the laser beam is actually scanned over the portion to be measured.
[0091]
In the region C, the height H indicates the flare amount (flare value) that is the protein concentration in the anterior chamber of the eye to be examined. Moreover, although not shown, the value which protrudes and becomes high in some places shows the cell (cell) which floats in the anterior chamber of the eye 1 to be examined.
[0092]
(Measurement result display)
When the measurement is completed, the output signal of the photoelectric detector 15 is analyzed by the analysis unit 9 and the measurement result is displayed on the display unit 8 as a display screen. The display of the display unit 8 is displayed when the analysis unit 9 controls the switch 10 to switch the display from the image display of the CCD camera 27 to the data display in the analysis unit 9.
[0093]
【The invention's effect】
As described above, the present invention can suppress the influence of disturbance light and increase the measurement accuracy.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a laser flare meter (LFM) according to an embodiment.
FIG. 2 is a detailed diagram illustrating an optical positional relationship with respect to an eye to be examined by a laser flare meter (LFM) according to an embodiment.
FIG. 3 is a detailed diagram illustrating an optical positional relationship between a projection light optical axis and a light reception optical axis of a laser flare meter (LFM) according to an embodiment.
FIG. 4 is a table showing the light intensity detected by the photoelectric detector according to the embodiment over time.
FIG. 5 is a detailed diagram for explaining the optical positional relationship between a projected light optical axis and a received light optical axis of a conventional laser flare meter (LFM).
6 is a table showing the light intensity received by the apparatus of FIG.
FIG. 7 is a detailed diagram for explaining the optical positional relationship between a projection light optical axis and a light reception optical axis of a conventional improved laser flare meter (LFM).
8 is a table showing the light intensity received by the apparatus of FIG.
[Explanation of symbols]
1 Eye to be examined
2 IOL
3 Measurement unit
4 Projection optical system
5 Light receiving optical system
6 XY direction alignment part
7 Z direction alignment part
8 Display section
9 Analysis Department
10 changer
L0 Eye optical axis
L0 'axis passing through the measurement target portion S parallel to the eyeball optical axis L0
L1 Projection optical axis
L2 Light receiving optical axis
L3 Reflected light optical axis
L4 cornea reflection light optical axis
L5 Reflected scattered light optical axis
L6 Incident optical axis
L7 Reflected light optical axis

Claims (2)

In an ophthalmologic measurement apparatus that measures biological characteristics in an eye to be examined by projecting light into the eye to be examined and receiving scattered light,
A projection optical system that projects projection light obliquely with respect to the eyeball optical axis of the eye to be examined from the light source into the eye to be examined;
A light receiving optical system for receiving the scattered light scattered by the measurement target portion in the eye to be examined;
With
The projection optical axis of the projection optical system and the light receiving optical axis of the light receiving optical system form a substantially right angle with the measurement target portion at the top,
The light receiving optical axis is an artificial axis reflected by an artificial crystalline lens when the projected light is assumed to be an optical axis of corneal reflected light reflected by the cornea when entering the eye to be examined and an artificial crystalline lens in which the projected light is inserted into the examined eye. It is set without intersecting any optical axis between the optical axis of the lens reflected light,
The distance between the light receiving optical axis and the optical axis of the corneal reflected light and the optical axis of the artificial crystalline lens reflected light is set to a distance that does not allow the optical receiving system to receive the corneal reflected light and the artificial crystalline lens reflected light. An ophthalmic measurement device characterized by the above. The light receiving optical system includes a light receiving element that receives the scattered light, and a light receiving optical path along the light receiving optical axis to the light receiving element, and a predetermined size at a position optically conjugate with the measurement target portion. A light-shielding member having an opening,
The ophthalmic measurement apparatus according to claim 1, wherein the light shielding member guides only the scattered light transmitted through the opening to the light receiving element.

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