A multifunctional eye parameter measuring instrument

Abstract

The invention discloses a multifunctional eye parameter measuring instrument, which is characterized by comprising an axial length measuring system and a refractive measurement system, or an axial length measuring system and a corneal base map measuring system, or an axial length measuring system, a refractive measurement system and a corneal base map measuring system; the refractive measurement system comprises a measuring light reflector, a wedge-shaped semi-transparent reflector, a refractive LED light source, a refracting reflector, a front group collimating mirror, a rear group collimating mirror, a compound eye lens, a refractive image acquisition device and a calibration LED lamp. The invention organically integrates a variety of ophthalmic parameter measurement systems into one device, eliminates the error caused by switching, realizes one machine with multiple uses, and fully meets the needs of the ophthalmic market.

Description

Technical Field

[0001] The invention relates to ophthalmic equipment, in particular to a multifunctional eye parameter measuring instrument. Background Art

[0002] Generally speaking, most ophthalmic devices on the market measure certain parameters, such as:

[0003] Axial length measuring instruments are usually used to measure the thickness of the eyeball from the cornea to the fundus, assist in measuring the corneal curvature, pupil size, and even scan and measure the eyeball to build its three-dimensional model to obtain a complete eyeball data simulation structure. Refractometers can only measure the refractive power of the human eye. Corneal floor topographs can only measure the corneal floor map. Currently, there is no device that can organically integrate several functions. Summary of the invention

[0004] In view of the problems in the prior art, the present invention provides a multifunctional eye parameter measuring instrument, which can integrate the measurement of multiple eye parameters in one device.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a multifunctional eye parameter measuring instrument, characterized in that: it includes an axial length measurement system and a refraction measurement system, or includes an axial length measurement system and a corneal base map measurement system, or includes an axial length measurement system, a refraction measurement system and a corneal base map measurement system;

[0006] The axial length measurement system includes an SLD light source, a sample arm, a reference arm, a coupler and a photoelectric sensor.

[0007] The coupler is used to divide the light generated by the SLD light source into two paths, and process them in the reference arm and the sample arm respectively, and optically modulate the reflected light returned by the reference arm and the sample arm and output them to the photoelectric sensor;

[0008] The sample arm comprises a first collimator and a low-pass reflector, wherein the first collimator is used to collimate the light from the coupler into a collimated light, and the collimated light enters the fundus after being reflected by the low-pass reflector;

[0009] The refractive measurement system comprises a measuring light reflector, a wedge-shaped semi-transparent reflector, a refractive LED light source, a refracting reflector, a front group collimating mirror, a rear group collimating mirror, a compound eye lens, a refractive image acquisition device and a calibration LED lamp. The measuring light reflector can be moved between the first collimating mirror and the low-pass reflector of the sample arm through a switching mechanism. The refractive LED light source is located on the back of the wedge-shaped semi-transparent reflector. The light emitted by the refractive LED light source passes through the wedge-shaped semi-transparent reflector and then irradiates the measuring light reflector. The light from the fundus is reflected by the low-pass reflector, the light from the fundus is reflected by the low-pass reflector, the measuring light reflector, the wedge-shaped semi-transparent reflector, and the refracting reflector in sequence, and then enters the front group of collimating mirrors, the rear group of collimating mirrors, the compound eye lens, and then enters the refractive image acquisition device. The calibration LED lamp is located above the back of the low-pass reflector. The light from the calibration LED lamp passes through the low-pass reflector, is reflected by the measuring light reflector, the wedge-shaped semi-transparent reflector, and the refracting reflector, and then enters the front group of collimating mirrors, the rear group of collimating mirrors, the compound eye lens, and then enters the image acquisition device.

[0010] The present invention adopts the OCT optical principle to measure the distance between the various surfaces of the eyeball. The light emitted by the SLD light source enters the sample arm through the coupler and is collimated by a collimator to become a collimated light. It then enters the eye after being reflected by a low-pass reflector. The reflected light on each surface returns to the coupler along the original path. The light emitted by the light source SLD, after passing through the coupler, another part enters the reference arm. The light of the reference arm is reflected by the reflector on the reference arm and returns to the coupler along the original path. The above two paths of light are output from the output end in the coupler and reach the photoelectric sensor. This part of the signal, after processing, can obtain the information collected by the light of the sample arm on each surface of the eye, that is, the thickness of each surface can be obtained, that is, the principle of measuring the axial length of the eye.

[0011] The measuring light reflector can be switched. That is to say, when the axial length of the eye is measured, it is switched out of the axial length measurement optical path. In other words, when measuring the axial length of the eye, if the diopter measurement function is not needed, it is not necessary to allow the diopter measurement light to enter the eye, so a switching mechanism is designed to switch the measuring light reflector away. The switching mechanism can be a motor-controlled screw nut mechanism, or other mechanisms such as a cylinder telescopic mechanism, as long as it can allow the measuring light reflector to leave and enter.

[0012] Correspondingly, when the diopter needs to be measured, the measuring light reflector cuts into the optical path. The measuring light reflector can only reflect light but not transmit it. Therefore, when the measuring light reflector enters the optical path, the light for measuring the axial length of the eye can no longer enter the eye. At this time, only the light for measuring the refraction is working.

[0013] When the measuring light reflector is switched each time, it is difficult to ensure that there is no reflection angle error after each switch into the optical path due to the motion switching structure. This slight error will directly cause the reflected light to deflect along the long optical path after entering the refractive image acquisition device. In order to offset this deflection error, we designed a calibration optical path:

[0014] The calibration LED light emitted by the calibration LED lamp is collimated light. After being projected through a low-pass reflector, it is reflected by the measuring light reflector, and then reflected by the wedge-shaped semi-transparent reflector, and enters the optical path until it appears as a relatively thin point image on the refractive image acquisition device. Since the measuring light reflector is a movable structure, there may be a slight error angle each time. Then, the position of the fine point image of the reflected light on the refractive image acquisition device will have a corresponding slight change. We assume it to be a value: deltaxy. We believe that this deltaxy is the error of the machine itself. Therefore, when taking specific measurements and samples, this detaxy will be subtracted, and then the position point of the central axis of the reflected light from the ocular surface will be determined. In this way, measurement errors caused by switching errors can be avoided.

[0015] The wedge-shaped semi-transparent reflector is designed with a wedge angle according to the characteristics of the optical path. Instead of a standard flat glass with two parallel sides, it is a flat glass with two surfaces (two reflective surfaces, i.e., the two surfaces close to the refractive LED light source and the two surfaces far away from the refractive LED light source) with an angle. The purpose of this design is to allow the near-infrared light to pass through it and be transmitted into the eye. When the light reflected from the eye passes through this glass part with two surfaces again, the light reflected from both surfaces will not enter the optical path, resulting in overlapping images. That is, the angle of the wedge-shaped semi-transparent reflector is used to prevent the light reflected from the two parallel surfaces from being transmitted in one direction. Therefore, it is designed to have a wedge shape so that the light reflected from the two surfaces is no longer parallel, thus avoiding ghost images on the image plane.

[0016] The above scheme also includes a corneal base map measurement system for measuring the corneal base map, the corneal base map measurement system includes a Placido disk, an imaging lens group and a corneal fundus image acquisition device, a center hole is provided at the center of the Placido disk, and multiple circles of apertures are provided on the Placido disk. The light emitted by the aperture of the Placido disk irradiates the fundus and enters the low-pass reflector after reflection. The light passing through the low-pass reflector enters the imaging lens group and then enters the corneal fundus image acquisition device.

[0017] The Placido disk has a hole in the center to allow light and lenses to pass through.

[0018] The corneal curvature and corneal base map can be measured. The schematic diagram of measuring corneal curvature is as follows Figure 2As shown in the figure, the halo (object point) at point A on the Placido disk is irradiated onto the cornea, and after being reflected by the cornea, it is imaged on the corneal fundus image acquisition device through the optical system. According to the distribution of image points on the corneal fundus image acquisition device, the corneal curvature and other characteristics can be calculated.

[0019] Corneal topography measurements Figure 4 As shown in the figure, the standard apertures A, B, .... on the Placido disk are illuminated in multiple circles. After passing through the optical system in the figure above, they are imaged on the corneal fundus image acquisition device. A, B, ... correspond to A', B'......

[0020] After the corneal fundus image acquisition device collects these multiple ring images, it can compare and calculate the measured corneal surface shape data by comparing with the standard corneal curvature data. This calculation method is a prior art.

[0021] In the above scheme, the first large objective lens of the imaging lens group is located in the central hole of the Placido disk. Such a structural design, instead of placing the imaging optical system behind the Placido disk, has the advantage of achieving the function while being compact in structure, and can take into account both corneal base map measurement and corneal curvature measurement.

[0022] The Placido disk of the present invention is designed on the principal optical axis of the axial length measurement system, which has the following advantages:

[0023] When measuring the corneal fundus pattern, the position of the patient (i.e. the eye being measured) needs to be exactly in the ideal position with the machine, which is called "alignment". The traditional existing technology is to install a light-emitting device and a receiving device on the left and right sides of the machine, and determine whether the alignment is ideal by sensing the position of the corneal reflected light. The present invention designs the Placido disk on the main optical axis of the axial length measurement system, which can not only realize the measurement of the corneal curvature radius, but also realize the alignment when measuring the axial length, and the alignment is accurate. That is to say, when OCT light (the above-mentioned axial length measurement function) is used for measurement, the light incident on the eye surface that coincides with the central optical axis is measured to obtain the interference signals of each surface of the eye until the human eye parameters can be measured. Under such an accurate premise, that is, when measuring the axial length, it has been aligned, and when measuring the axial length, the alignment is also required to be very accurate. This is far more reliable than the traditional method of using only the reflected light from the eye surface as the basis for determining the alignment! More accurate.

[0024] In the above scheme: the position of the refractive LED light source satisfies the requirement that the light reflected from the ocular surface deviates from the vertical axis of the center of the ocular surface, so that the light reflected from the ocular surface does not enter the refractive image acquisition device.

[0025] Preferably, the light reflected from the ocular surface deviates from the vertical axis of the center of the ocular surface by an angle of 0°-3°

[0026] Adjust the position of the refractive LED light source so that the light reflected from the ocular surface deviates from the vertical axis in the center of the ocular surface, so that the light reflected from the ocular surface does not enter the refractive image acquisition device. In other words, make a slight adjustment to the incident angle so that when the near-infrared measurement working light is directed to the ocular surface, the reflected light has a slight angle with the vertical axis in the center of the ocular surface before entering the refractive image acquisition device, causing the reflected light to have a slight axial deviation when it is reflected by the ocular surface, thereby causing the reflected light to deviate from entering the image plane and generate stray light.

[0027] Preferably, the included angle between the two reflecting surfaces of the wedge-shaped semi-transparent reflector is 1°-5°.

[0028] In the above scheme: the refractive image acquisition device and the corneal fundus image acquisition device are both CCD.

[0029] In the above scheme: the reference arm includes a second collimator, two corner cube prisms and a reflector. The light coming out of the coupler is collimated into collimated light by the second collimator, and then reaches the reflector after passing through the two corner cube prisms. The light reflected by the reflector returns to the coupler along the original path.

[0030] In the above scheme, a rotatable flat glass for light to pass through is arranged obliquely between the first collimator and the low-pass reflector, and the measuring light reflector can be switched between the flat glass and the low-pass reflector. This means that the light passes through the flat glass and the surface of the flat glass is not perpendicular to the direction of the optical axis. The flat glass is driven to rotate by a motor and a gear mechanism, and this mechanism is a conventional rotating mechanism. The rotating flat glass is set to allow the parallel collimated light to penetrate the rotating flat glass, so that the light after passing through the flat glass moves in a circle. The light entering the eye is caused to shake in a larger range, making it easier to capture the required data.

[0031] Since the human eye always has a slight shake within a time range, it is difficult to completely fix it. In addition, since the visual axis and the optical axis of the human eyeball have a certain angle of deviation, if the light entering the eye is perpendicular to the macula of the fundus according to the visual axis, it will inevitably be non-perpendicular to the eyeball, and the reflected light on the surface of the lens will also have a deflection angle, which makes it very difficult to collect the reflected light, that is, it is difficult to enter the original emission point. Therefore, allowing the incident light to rotate with the visual axis of the eyeball will solve the above-mentioned problems.

[0032] That is, the inclined flat glass rotates at high speed driven by the motor, causing the collimated straight light beam to move in a circle, so that the circle range covers a certain range around the eye axis, making it easier to collect the reflected light and enter the original emission point, making it easier to capture the required data.

[0033] In the above solution, the inclination angle of the flat glass is 0.1°-5°.

[0034] Beneficial effects: The present invention organically integrates a variety of ophthalmic parameter measurement systems into one device, eliminates the errors caused by switching, realizes multiple uses of one device, and fully meets the needs of the ophthalmic market. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the optical structure of the present invention.

[0036] Figure 2 This is the principle diagram of corneal curvature radius measurement.

[0037] Figure 3 Schematic diagram of the corneal topography measurement system.

[0038] Figure 4 Schematic diagram of existing alignment method. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with embodiments and drawings.

[0040] Example 1

[0041] like Figure 1-3 As shown, the multifunctional eye parameter measuring instrument of the embodiment of the present invention includes an axial length measuring system, a refraction measuring system and a corneal base map measuring system for measuring a corneal base map.

[0042] Of course, in actual use, only the combination of the axial length measurement system and the refractive measurement system, or the combination of the axial length measurement system and the corneal base map measurement system may be selected.

[0043] The axial length measurement system includes an SLD light source 1, a sample arm, a reference arm, a coupler 2 and a photoelectric sensor 3.

[0044] The coupler 2 is used to split the light generated by the SLD light source 1 into two paths, and process them in the reference arm and the sample arm respectively, and optically modulate the reflected light returning from the reference arm and the sample arm and output it to the photoelectric sensor 3.

[0045] The sample arm comprises a first collimator 4 and a low-pass reflector 5. The first collimator 4 is used to collimate the light from the coupler 2 into a collimated light beam. The collimated light beam enters the fundus after being reflected by the low-pass reflector 5.

[0046] The reference arm includes a second collimator 6, two corner cube prisms 7 and a reflector 8. The light coming out of the coupler 2 is collimated by the second collimator 6 into collimated light, and then passes through the two corner cube prisms 7 to reach the reflector 8. The light reflected by the reflector 8 returns to the coupler 3 along the original path.

[0047] A rotatable flat glass 21 for light to pass through is tiltedly arranged between the first collimator 4 and the low-pass reflector 5 and close to the first collimator 4 . The tilt angle of the flat glass 21 is 0.1°-5°.

[0048] The refractive measurement system includes a measuring light reflector 9, a wedge-shaped semi-transparent reflector 10, a refractive LED light source 11, a refracting reflector 12, a front group collimator 13, a rear group collimator 14, a compound eye lens 15, a refractive image acquisition device 16 (CCD can be selected) and a calibration LED lamp 17. The measuring light reflector 9 can be moved between the first collimator 4 and the low-pass reflector 5 of the sample arm through a switching mechanism, and the measuring light reflector is switched to enter between the flat glass and the low-pass reflector. In other words, when the axial length of the eye is measured, it is switched away and is not in the axial length measurement optical path. That is, when measuring the axial length of the eye, if the diopter function is not needed, the light measuring the diopter does not need to be injected into the eye, so a switching mechanism is designed to switch the measuring light reflector away. The switching mechanism can be a screw nut mechanism controlled by a motor, or it can be other mechanisms such as a cylinder telescopic mechanism, as long as the measuring light reflector can be allowed to leave and enter.

[0049] Correspondingly, when the diopter needs to be measured, the measuring light reflector 9 cuts into the optical path. The measuring light reflector 9 can only reflect light but not transmit it. Therefore, when the measuring light reflector 9 enters the optical path, the light for measuring the axial length of the eye can no longer enter the eye. At this time, only the light for measuring the diopter is working.

[0050] The angle between the two reflecting surfaces of the wedge-shaped semi-transparent reflector 10 is 1°-5°, that is, the angle between the surface close to the refractive LED light source 11 and the surface far away from the refractive LED light source 11 in the figure is 1°-5°. The refractive LED light source 11 is located on the back of the wedge-shaped semi-transparent reflector 10. The light emitted by the refractive LED light source 11 passes through the wedge-shaped semi-transparent reflector 10 and then irradiates the measuring light reflector 9. After being reflected by the measuring light reflector 9 and the low-pass reflector 5, it enters the fundus. The fundus reflected light is reflected by the low-pass reflector 5, the measuring light reflector 9, the wedge-shaped semi-transparent reflector 10, and the refractive reflector 12 in sequence, and then enters the front group collimator 13, the rear group collimator 14, the compound eye lens 15, and then enters the refractive image acquisition device 16. The position of the refractive LED light source 11 satisfies the requirement that the light reflected from the ocular surface deviates from the vertical axis of the center of the ocular surface, so that the light reflected from the ocular surface does not enter the refractive image acquisition device 16. Preferably, the light reflected from the ocular surface deviates from the vertical axis of the center of the ocular surface at an angle of 0°-3°.

[0051] Since the measuring light reflector 9 is switched in and is a moving switching structure, it is difficult to ensure that there is no reflection angle error every time it switches into the optical path. This slight error directly causes the reflected light to deflect along the long optical path after entering the CCD. In order to offset this deflection error, a calibration optical path is designed. The calibration LED lamp 17 is located above the back of the low-pass reflector 5. The light of the calibration LED lamp 17 passes through the low-pass reflector 5 and is reflected by the measuring light reflector 9, the wedge-shaped semi-transparent reflector 10, and the refractive reflector 12, and then enters the front group collimator 13, the rear group collimator 14, and the compound eye lens 15 and enters the image acquisition device 16. A relatively thin point image appears on the refractive image acquisition device. Since the measuring light reflector is a movable structure, there may be a slight error angle each time. Then, the position of the fine point image of the reflected light on the refractive image acquisition device will have a corresponding slight change. We assume it to be a value: deltaxy. We believe that this deltaxy is the error of the machine itself. Therefore, when measuring and sampling, the detaxy will be subtracted to determine the location of the central axis of the reflected light from the eye surface. In this way, the measurement error caused by switching error can be avoided.

[0052] The corneal base map measurement system includes a Placido disk 18, an imaging lens group 19 and a corneal fundus image acquisition device (CCD can be selected) 20. A central hole is provided at the center of the Placido disk 18. Multiple apertures are provided on the Placido disk 18 from the outside to the inside. The structure of the Placido disk 18 is the prior art. The light emitted from the aperture of the Placido disk irradiates the fundus and enters the low-pass reflector 5 after reflection. The light passing through the low-pass reflector 5 enters the imaging lens group 19 and then enters the corneal fundus image acquisition device 20. The first large objective lens of the imaging lens group 19 is located in the central hole of the Placido disk 18.

[0053] like Figure 1-2 Schematic diagram for measuring corneal curvature: Point A on the Placido disk represents a circle of light (object point), which is irradiated onto the cornea, reflected by the cornea, and imaged on the corneal fundus image acquisition device 20 through the optical system. According to the distribution of image points on the corneal fundus image acquisition device 20, the corneal curvature and other characteristics can be calculated.

[0054] like Figure 3 As shown in the figure, the standard apertures A, B, .... on the Placido disk are illuminated in multiple circles. After passing through the optical system in the figure above, they are imaged on the corneal fundus image acquisition device. A, B, ... correspond to A', B'......

[0055] After the corneal fundus image acquisition device collects these multiple ring images, it can compare and calculate the measured corneal surface shape data by comparing with the standard corneal curvature data. This calculation method is a prior art.

[0056] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention. In actual use, the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multifunctional eye parameter measuring instrument, characterized in that: It includes an axial length measurement system and a refraction measurement system, or includes an axial length measurement system and a corneal base map measurement system, or includes an axial length measurement system, a refraction measurement system and a corneal base map measurement system; The axial length measurement system includes an SLD light source, a sample arm, a reference arm, a coupler and a photoelectric sensor. The coupler is used to divide the light generated by the SLD light source into two paths, and process them in the reference arm and the sample arm respectively, and optically modulate the reflected light returned by the reference arm and the sample arm and output them to the photoelectric sensor; The sample arm comprises a first collimator and a low-pass reflector, wherein the first collimator is used to collimate the light from the coupler into a collimated light, and the collimated light enters the fundus after being reflected by the low-pass reflector; The refractive measurement system comprises a measuring light reflector, a wedge-shaped semi-transparent reflector, a refractive LED light source, a refracting reflector, a front group collimating mirror, a rear group collimating mirror, a compound eye lens, a refractive image acquisition device and a calibration LED lamp. The measuring light reflector can be moved between the first collimating mirror and the low-pass reflector of the sample arm by a switching mechanism. The refractive LED light source is located on the back of the wedge-shaped semi-transparent reflector. The light emitted by the refractive LED light source is irradiated onto the measuring light reflector after passing through the wedge-shaped semi-transparent reflector. The light is reflected by the measuring light reflector and the low-pass reflector and enters the fundus. The fundus reflected light is reflected by the low-pass reflector, the measuring light reflector, the wedge-shaped semi-transparent reflector and the refracting reflector in sequence and enters the front group collimating mirror, the rear group collimating mirror and the compound eye lens and then enters the refractive image acquisition device. The calibration The LED light is located above the back of the low-pass reflector. The calibration LED light emitted by the calibration LED light is collimated light. The light of the calibration LED light passes through the low-pass reflector and is reflected by the measuring light reflector, the wedge-shaped semi-transparent reflector, and the refractive reflector before entering the front collimator, the rear collimator, the compound eye lens, and finally the image acquisition device. Since the measuring light reflector is a movable structure, there may be a slight error angle each time, and the position of the fine point image of the reflected light on the refractive image acquisition device will have a corresponding slight change, which is set as a value: deltaxy, which is the error of the machine itself. When taking specific measurements and samples, deltaxy will be subtracted to determine the position point of the central axis of the reflected light from the eye surface to avoid measurement errors caused by switching errors. The corneal base map measurement system comprises a Placido disk, an imaging lens group and a corneal fundus image acquisition device. The Placido disk is designed on the main optical axis of the axial length measurement system. A central hole is provided at the center of the Placido disk. Multiple apertures are arranged on the Placido disk. Light emitted from the apertures of the Placido disk irradiates the fundus and enters a low-pass reflector after reflection. The light passing through the low-pass reflector enters the imaging lens group and then enters the corneal fundus image acquisition device. The first large objective lens of the imaging lens group is located in the central hole of the Placido disk.

2. The multifunctional eye parameter measuring instrument according to claim 1, characterized in that: The position of the refractive LED light source is such that the light reflected from the ocular surface deviates from the vertical axis of the center of the ocular surface, so that the light reflected from the ocular surface does not enter the refractive image acquisition device.

3. The multifunctional eye parameter measuring instrument according to claim 2, characterized in that: The light reflected from the ocular surface deviates from the vertical axis at the center of the ocular surface at an angle of 0°-3°.

4. The multifunctional eye parameter measuring instrument according to claim 3, characterized in that: The included angle between the two reflecting surfaces of the wedge-shaped semi-transparent reflecting mirror is 1°-5°.

5. The multifunctional eye parameter measuring instrument according to claim 4, characterized in that: The refractive image acquisition device and the corneal fundus image acquisition device are both CCDs.

6. The multifunctional eye parameter measuring instrument according to claim 1, characterized in that: The reference arm includes a second collimator, two corner cube prisms and a reflector. The light from the coupler is collimated into collimated light by the second collimator, and then reaches the reflector after passing through the two corner cube prisms. The light reflected by the reflector returns to the coupler along the original path.

7. The multifunctional eye parameter measuring instrument according to claim 1, characterized in that: A rotatable flat glass for light to pass through is tiltedly arranged between the first collimator and the low-pass reflector at a position close to the first collimator, and the measuring light reflector can be switched between the flat glass and the low-pass reflector.

8. The multifunctional eye parameter measuring instrument according to claim 7, characterized in that: The inclination angle of the flat glass is 0.1-5°.

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