Multi-parameter eye health measuring device for ophthalmology department

Abstract

An ophthalmic device for multiple eye health measurements is provided. The ophthalmic apparatus includes: an objective lens module for collecting and initially focusing an image of an eye of a subject; the sight fixing mark is used for fixing the eyes of the detected person at a watching position; the corneal topography measuring unit is used for measuring corneal geometric parameters; a fundus imaging unit for imaging a fundus; the first light beam separator is used for separating or combining light paths among the objective lens module, the corneal topography measuring unit and the fundus imaging unit; and a second beam splitter for deflecting the beam from the fixation target to the eye of the subject. The objective lens module, the fixation target, the first beam splitter and the second beam splitter are shared by the corneal topography measuring unit and the fundus imaging unit, so that the size and complexity of the whole system can be reduced.

Description

Technical Field

[0001] The present invention generally relates to ophthalmic measurement techniques. More specifically, the present invention relates to an ophthalmic measurement device capable of performing corneal topography measurement, fundus imaging, and axial length estimation. Background Art

[0002] Eye health and vision are crucial for overall health. However, many people have difficulty accessing affordable and high-quality ophthalmic care. These barriers contribute to the prevalence of visual impairment and blindness, even though nearly 50% of these cases can be prevented through early diagnosis and regular monitoring. Despite technological advancements in ophthalmic care, traditional devices often have significant drawbacks. Many devices are designed for only a single function, limiting their use in large-scale screening. A comprehensive eye examination typically requires multiple devices, resulting in high costs. Additionally, some devices require manual alignment, which is cumbersome and time-consuming for inexperienced operators. Summary of the Invention

[0003] The object of the present invention is to provide a single device that allows users to examine multiple parts of the eye to obtain comprehensive corneal, fundus, and axial length information. This innovation will simplify the eye health assessment process, improve measurement efficiency, and reduce the overall cost of ophthalmic care.

[0004] According to a first aspect of the present invention, there is provided an ophthalmic device. The device includes: an objective lens module configured to collect and initially focus an image of the eye of a subject; a fixation target configured to fix the eye of the subject at a fixation position; a corneal topography measurement unit for measuring geometric parameters of the cornea of the subject; a fundus imaging unit for imaging the fundus of the subject; a controller configured to control the corneal topography measurement unit and the fundus imaging unit to obtain eye data of the subject; a processor configured to perform predetermined processing on the obtained eye data; a first beam splitter configured to split the optical path from the objective lens module to the corneal topography measurement unit and the fundus imaging unit, or to converge the optical paths from the corneal topography measurement unit and the fundus imaging unit to the objective lens module respectively; and a second beam splitter configured to deflect the beam from the fixation target to the eye of the subject. The objective lens module, the fixation target, the first beam splitter, and the second beam splitter are shared by the corneal topography measurement unit and the fundus imaging unit. Description of the Drawings

[0005] Embodiments of the present invention will be described in more detail hereinafter with reference to the accompanying drawings, in which:

[0006] Figure 1A and 1B show a perspective view and a side view of an ophthalmic device according to an embodiment of the present invention respectively.

[0007] Figure 1C is for explaining Figure 1A and 1B the simplified schematic diagram of the optical components of the ophthalmic device shown in

[0008] Figure 2 The schematic diagram of the corneal topographer unit according to an embodiment of the present invention is shown.

[0009] Figure 3 shows Figure 2 the ray tracing model of the corneal topographer unit shown in

[0010] Figure 4A The Placido ring light source generator according to an embodiment of the present invention is shown.

[0011] Figure 4B The Placido disk formed by the Placido ring light source generator is shown.

[0012] Figure 5 The ray tracing diagram of the LED emitter according to an embodiment of the present invention is shown.

[0013] Figures 6A to 6D The front isometric view, rear isometric view, front view and rear view of the primary lens of the LED emitter are respectively shown.

[0014] Figure 7 and 8 shows the beam profile simulation result of the LED emitter.

[0015] Figure 9 The schematic diagram of the fundus imaging unit according to an embodiment of the present invention is shown.

[0016] Figure 10A and 10B The ray tracing models of the illumination optical path and the imaging optical path of the fundus imaging unit are respectively shown.

[0017] Figure 11 An exemplary design of the fundus illumination light source is shown.

[0018] Figure 12A and 12B The front view and rear view of the illumination light source are respectively shown.

[0019] Figure 13 An exemplary design of the gradient photoresist filter is shown.

[0020] Figure 14A and 14BRespectively shown are the fundus image simulation obtained using the fundus imaging unit according to the present invention, and the comparative simulation results using a single LED without a stray light elimination unit.

[0021] Figure 15 Shown is the corneal image obtained by the ophthalmic device provided by the present invention.

[0022] Figure 16A and 16B Respectively shown are 3D models of the corneal curvature and corneal height reconstructed from the corneal image data.

[0023] Figure 17 Shown is the fundus image obtained by the ophthalmic device provided by the present invention. Detailed Description of the Invention

[0024] In the following description, details of the present invention are illustrated in the form of preferred embodiments. It is obvious to those skilled in the art that modifications, including additions and / or substitutions, can be made without departing from the scope and spirit of the present invention. To avoid obscuring the present invention, specific details may be omitted; however, the purpose of this disclosure is to enable those skilled in the art to practice the teachings of the present invention without excessive experimentation.

[0025] Figure 1A and 1B Shown is an ophthalmic device 1 according to an embodiment of the present invention. Figure 1C is a simplified schematic diagram of the optical components of the ophthalmic device. As shown, the ophthalmic device 1 includes a corneal topographer unit 2 for measuring geometric parameters of the cornea of the subject to be examined, and a fundus imaging unit 3 for imaging the fundus of the subject to be examined.

[0026] The ophthalmic device 1 includes an objective lens module 11 for collecting light from the eye of the subject to be examined and performing initial focusing. The objective lens module 11 may include one or more lenses arranged in sequence along the optical axis of the objective lens module 11.

[0027] As Figure 3 shown, in one embodiment, the objective lens module 11 may include a first lens 111, a second lens 112 beside the first lens 111, a third lens 113 beside the second lens 112, and a fourth lens 114 beside the third lens 113. The first lens 111 may be a plano-convex lens. The second lens 112 may be a biconvex lens. The third lens 113 may be a biconcave lens. The second lens 112 and the third lens 113 may form a doublet lens group. The fourth lens 114 may be a biconvex lens. Each of the lenses 111 to 114 may be made of glass, plastic, or any suitable optical material.

[0028] The ophthalmic device 1 further includes a fixation target 20 for fixing the eye of the subject at a fixation position. The fixation target 20 may include a plurality of light-emitting diodes (LEDs) arranged in any suitable pattern. For example, the fixation target 20 may include a first LED located at a central position, and a plurality of second LEDs arranged around the first LED in a circular symmetric pattern.

[0029] The ophthalmic device 1 further includes a first beam splitter 31 for separating the optical path from the objective lens module 11 to the corneal topographer unit and the fundus imaging unit 3, or for converging the optical paths from the corneal topographer unit and the fundus imaging unit 3 to the objective lens module 11 respectively.

[0030] The ophthalmic device 1 further includes a second beam splitter 32 for deflecting the light beam from the fixation target 20 to the eye of the subject.

[0031] The ophthalmic device 1 further includes a control unit (not shown) for controlling the corneal topographer unit 2 and the fundus imaging unit 3 to obtain the eye data of the subject; and a processing unit (not shown) for immediately processing the obtained ophthalmic data. The ophthalmic device 1 may also include a storage unit (not shown) for storing the obtained data and preset processing methods and algorithms. Alternatively, the control unit and the processing unit may each include a corresponding memory for storing the obtained data and preset processing methods and algorithms.

[0032] The objective lens module 11, the fixation target 20, the first beam splitter 31 and the second beam splitter 32 are shared by the corneal topographer unit 2 and the fundus imaging unit 3, thereby reducing the size and complexity of the overall system.

[0033] Figure 2 A schematic diagram of the corneal topographer unit 2 is shown. Figure 3 An exemplary ray tracing model of the corneal topographer unit 2 is shown.

[0034] As shown in the figure, in addition to the objective lens module 11, the fixation target 20, the first beam splitter 31 and the second beam splitter 32, the corneal topographer unit 2 further includes a projector 41, a corneal image sensor 51 and a corneal imaging lens module 12. The projector 41 is used for projecting an annular light pattern onto the cornea of the subject. The corneal image sensor 51 is used for photographing the return light of the annular light pattern reflected from the cornea of the subject. The corneal imaging lens module 12 is used for focusing the return light reflected from the cornea of the subject to form an image of the cornea of the subject including the annular light pattern on the corneal image sensor.

[0035] The projector 41 may be configured as a Placido annular light generator to generate a plurality of concentric annular patterns on the cornea of the subject. See Figure 4A, the projector 41 includes a plurality of concentric annular light sources. Each annular light source includes an annular LED emitter 411. Essentially, the plurality of concentric annular light sources form a Placido disk as shown in Figure 4B to project a plurality of Placido rings onto the cornea. By capturing and analyzing the reflection of the Placido rings by the cornea, any distortion of the reflection pattern caused by irregular regions (such as steep or flat regions) in the corneal shape can be detected, thereby obtaining the shape and curvature information of the cornea.

[0036] As shown in Figure 5 , each LED emitter 411 includes a near-infrared LED 4111 and a lens 4112 mounted on top of the LED. Figures 6A to 6D The front isometric view, back isometric view, front view, and back view of the lens are respectively shown. Figure 7 and Figure 8 show the beam profile simulation results of the LED emitter. By adopting the main lens, the LED emitter can achieve a beam angle of about 140°; and the beam illuminance uniformity (i.e., the percentage change in the radiation intensity distribution within the beam) is greater than 85%.

[0037] The corneal image sensor can be selected from a charge-coupled device (CCD) sensor, a complementary metal-oxide semiconductor (CMOS) sensor, or any other suitable type of image sensor. The corneal image sensor can be configured to image the cornea and output an image signal regarding the cornea of the subject to the processing unit at a predetermined rate. Based on the image signal, the processing unit can measure the curvature of the cornea and calculate the corneal height.

[0038] In one embodiment, the corneal imaging lens module 12 may include a first lens 121, a second lens 122 (located beside the first lens 121), a third lens 123 (located beside the second lens 122), a fourth lens 124 (located beside the third lens 123), a fifth lens 125 (located beside the fourth lens 124), and a sixth lens 126 (located beside the fifth lens 125). The first lens 121 can be a negative meniscus lens. The second lens 122 can be a biconvex lens. The third lens 123 can be a biconcave lens. The fourth lens 124 can be a biconvex lens. The fifth lens 125 can be a biconvex lens. The sixth lens 126 can be a negative meniscus lens. Each of the lenses 121 to 126 can be made of glass, plastic, or any suitable optical material.

[0039] Figure 9 The schematic diagram of the fundus imaging unit 3 is shown. Figure 10A and 10B respectively show exemplary ray tracing models of the illumination optical path and the imaging optical path of the fundus imaging unit 3.

[0040] As shown in the figure, in addition to the objective lens module 11, the fixation target 20, the first beam splitter 31 and the second beam splitter 32, the fundus imaging unit 3 further includes: a fundus illumination light source 42 for generating fundus imaging illumination light for capturing a fundus image; a fundus illumination lens module 13 for uniformly projecting the fundus imaging illumination light onto the fundus; a fundus image sensor 52 for capturing the light reflected from the fundus of the subject; a fundus imaging zoom lens module 14 for focusing the light reflected from the fundus of the subject to form a clear image of the fundus of the subject, i.e., an image of the retina of the eye; and a third beam splitter 33 located between the imaging optical path and the autofocus optical path of the fundus imaging unit 3 for splitting the light between the fundus illumination light source 42 and the eye of the subject, and between the fundus imaging sensor 52 and the eye of the subject.

[0041] In one embodiment, the fundus illumination lens module 13 may include a first lens 131 and a second lens 132, and the second lens 132 is located beside the first lens 131. The first lens 131 may be a plano-convex lens. The second lens 132 may be a plano-convex lens. The lenses 131 to 132 may be made of glass, plastic or any other suitable optical material.

[0042] The fundus image sensor 52 may be selected from a charge-coupled device (CCD) sensor, a complementary metal-oxide semiconductor (CMOS) sensor, or any other suitable type of image sensor. The fundus image sensor 52 may be configured to image the fundus and output an image signal regarding the fundus of the subject's eye to the processing unit at a predetermined rate.

[0043] In one embodiment, the fundus imaging zoom lens module 14 may include a first lens 141, a second lens 142 adjacent to the first lens 141, a third lens 143 adjacent to the second lens 142, and a fourth lens 144 adjacent to the third lens 143. The first lens 141 and the second lens 142 may form a doublet lens group. The third lens 143 and the fourth lens 144 may form a doublet lens group. The first lens 141 may be a biconcave lens. The second lens 142 may be a biconvex lens. The third lens 143 may be a negative meniscus lens. The fourth lens 144 may be a plano-convex lens. Each of the lenses 141 to 144 may be made of glass, plastic or any suitable optical material.

[0044] The fundus imaging zoom lens module 14 may further include an autofocus lens 15, which is located between the third beam splitter 33 and the first lens 141 and is configured to adjust the effective focal length of the fundus imaging zoom lens module 14. In one embodiment, the autofocus lens 15 may be a liquid lens connected to the control unit. The control unit is configured to analyze the sharpness of the fundus image captured by the fundus image sensor 52 under the illumination of the autofocus illumination light and generate an electrical signal to control the focal length of the liquid lens until a clear image is obtained.

[0045] In some embodiments, the fundus illumination light source 42 may include an imaging illumination light source 421, which is configured to generate white light annular light as the imaging illumination light; and an autofocus illumination light source 422, which is configured to generate near-infrared annular light as the autofocus illumination light. Figure 11 An exemplary design of the illumination light sources 421 / 422 is shown. Figure 12A and 12B The front view and the rear view of the illumination light sources 421 / 422 are shown respectively. As shown, the illumination light sources 421 / 422 may include annular LED light emitters 4211 / 4221, and PCBs 4212 / 4222 for mounting the LED light emitters 4211 / 4221 and providing electrical connections between them and the control unit.

[0046] In some embodiments, the imaging and autofocus illumination light sources 421 and 422 may be arranged orthogonally. The fundus illumination light source 42 may further include a fourth beam splitter 34, which is disposed at the intersection of the optical axes of the imaging illumination light source 421 and the autofocus illumination light source 422 and is configured to converge the imaging illumination light and the autofocus illumination light and direct them to the fundus illumination lens module 13.

[0047] The fundus imaging unit 3 may further include a relay lens module 16 located between the objective lens module 11 and the fundus imaging zoom lens module 14 for extending the imaging optical path and the illumination optical path of the fundus imaging unit 3.

[0048] In one embodiment, the relay lens module 16 may include a first lens 161, a second lens 162 (located beside the first lens 161), a third lens 163 (located beside the second lens 162), and a fourth lens 164 (located beside the third lens 163). The third lens 163 and the fourth lens 164 may form a doublet lens group. The first lens 161 may be a biconvex lens. The second lens 162 may be a positive meniscus lens. The third lens 163 may be a negative meniscus lens. The fourth lens 164 may be a negative meniscus lens. The third and fourth lenses 163 and 164 may form a doublet lens group. The lenses 161 to 164 may be made of glass, plastic, or any suitable optical material.

[0049] The fundus imaging unit 3 may further include a gradient light resistance filter 60, which is located in the optical path between the fundus illumination lens module 13 and the fundus imaging zoom lens module 14; a first polarizer 71, which is located between the fundus illumination light source 42 and the fundus illumination lens module 13; and a second polarizer 72, which is located between the fundus imaging zoom lens module 14 and the fundus imaging sensor 52. The polarization directions of the first and second polarizers 71 and 72 are set to be perpendicular to each other. The gradient light resistance filter 60 and the first and second polarizers 71 and 72 together form a stray light elimination module for removing stray light generated in the fundus imaging unit 3, such as stray light from the cornea, the objective lens module 11, the fundus illumination lens module 13, and the relay lens module 16. Figure 13 An exemplary design of the gradient light resistance filter 60 is shown. As shown, the gradient light resistance filter 60 may have a light-blocking region 601, where the light transmittance is the lowest at the center and gradually increases from the center to the periphery.

[0050] Figure 14A and 14B Shows a simulation of a fundus image obtained using the fundus imaging unit according to the present invention, as well as a comparative simulation result using a single LED without a scattered light elimination unit. As shown, the present invention can provide a more uniform illumination distribution and avoid any unwanted light spots that may occur in the comparative design.

[0051] Figure 15 Shows a corneal image obtained by the ophthalmic device provided by the present invention. Figure 16A and 16B Show 3D models of the corneal curvature and corneal height reconstructed from the corneal image data, respectively. Figure 17 Shows a retinal image obtained by the ophthalmic device provided by the present invention.

[0052] Based on the calibrated optical path length difference, the autofocus adjustment value, and the average corneal curvature value, the axial length of the eye to be examined can be estimated. Specifically, the axial length can be estimated by the following formula:

[0053] L A = 24 - (P R + R CC - 43 + a(3.6 - D AC )) / a, (1)

[0054] where L A represents the axial length of the eye to be examined, D AC represents the anterior chamber depth, P R represents the refractive power of the eye to be examined, R CC represents the corneal radius of curvature (in diopters), and a is an empirical constant.

[0055] By adjusting the drive current I that controls the curvature of the liquid lensliquid , calibrate the refractive power P R and the liquid lens driving current I liquid such that the refractive power P of the eye to be examined R can be used as an intermediate quantity for measuring the axial length of the eye to be examined.

[0056] By using a standard artificial eye model as a calibration sample and changing the refractive power of the eye model while keeping the known axial length, the anterior chamber depth D AC and the value of the constant a are determined to be 3.4 mm and 2.25 D respectively. Equation (1) can be simplified to:

[0057] L A = 24 - (P R + r CC - 43 + 0.45) / 2.25. (2)

[0058] Since P R is a calibration parameter and R CC can be derived from the topographic map image of the corneal measurement unit, the axial length L of the eye to be examined can thus be obtained A as the final output.

[0059] Although the present disclosure has been described and illustrated with reference to its specific embodiments, such descriptions and illustrations are not restrictive. The schematic diagrams may not be drawn to scale. Due to manufacturing processes and tolerances, there may be differences between the artistic representations in the present disclosure and the actual devices. There may be other embodiments of the present disclosure that are not specifically shown. Modifications may be made to specific situations, materials, compositions of matter, methods, or processes to adapt to the objectives and scope of the present disclosure. All such modifications are considered to fall within the scope of the appended claims. Although the methods described in the present disclosure are referenced to specific operations performed in a specific order, it should be understood that these operations may be combined, decomposed, or reordered to form equivalent methods without departing from the teachings of the present disclosure. Therefore, unless explicitly stated in the present disclosure, the order and grouping of operations do not constitute a limitation.

Claims

1. An ophthalmic device, comprising: An objective lens module configured to collect and initially focus an image of the eye of a subject; A fixation target configured to fix the eye of the subject at a fixation position; A corneal topographer for measuring geometric parameters of the cornea of the subject; A fundus imaging unit for imaging the fundus of the subject; A controller configured to control the corneal topographer and the fundus imaging unit to obtain eye data of the subject; A processor configured to perform preset processing on the obtained eye data; A first beam splitter configured to separate the optical path of the objective lens module to the corneal topographer and the fundus imaging unit, or to converge the optical paths of the corneal topographer and the fundus imaging unit to the objective lens module respectively; And A second beam splitter configured to deflect the beam of the fixation target to the eye of the subject; Wherein, the objective lens module, the fixation target, the first beam splitter and the second beam splitter are shared by the corneal topographer and the fundus imaging unit.

2. The ophthalmic device according to claim 1, wherein the corneal topographer comprises: A projector for projecting an annular light pattern onto the cornea of the subject; A corneal image sensor configured to capture the annular light pattern reflected from the cornea of the subject; And A corneal imaging lens module configured to focus the light reflected from the cornea of the subject and form a corneal image containing the annular light pattern on the corneal image sensor.

3. The ophthalmic device according to claim 2, wherein the projector is configured as a Placido annular light generator for generating a plurality of concentric annular patterns on the cornea of the subject.

4. The ophthalmic device according to claim 3, wherein the Placido annular light generator comprises a plurality of concentric Placido annular light sources.

5. The ophthalmic device according to claim 4, wherein each Placido annular light source comprises an LED light emitting ring; each said LED light emitting ring comprises an LED and a lens located on top of the LED.

6. The ophthalmic device according to claim 1, wherein the fundus imaging unit comprises: A fundus illumination light source configured to generate imaging illumination light for capturing an image of the fundus; A fundus illumination lens module configured to project the illumination light evenly onto the fundus; A fundus image sensor configured to capture the light reflected from the fundus of the subject; And A fundus imaging zoom lens module configured to focus the light reflected from the fundus of the subject on the fundus image sensor to form a fundus image of the subject.

7. The ophthalmic device according to claim 6, wherein The fundus imaging zoom lens module comprises an autofocus lens for adjusting the focal length of the fundus imaging zoom lens module; and The fundus illumination light source is further configured to generate autofocus illumination light for providing illumination for focusing of the fundus imaging zoom lens module.

8. The ophthalmic device according to claim 7, wherein the fundus illumination light source comprises: An imaging illumination light source for generating white light annular light; And An autofocus illumination light source for generating a near-infrared annular light.

9. The ophthalmic device according to claim 6, wherein the fundus imaging unit further includes a relay lens module located between the objective lens module and the fundus imaging zoom lens module for extending the imaging optical path and the illumination optical path of the fundus imaging unit.

10. The ophthalmic device according to claim 1, wherein the fundus imaging unit further includes: A gradient light resistance filter located in the optical path between the fundus illumination lens module and the fundus imaging zoom lens module; A first polarizer located between the fundus illumination light source and the fundus illumination lens module; And A second polarizer located between the fundus imaging zoom lens module and the fundus image sensor; and wherein the polarization directions of the first polarizer and the second polarizer are arranged orthogonally; and The gradient light resistance filter, the first polarizer and the second polarizer together constitute a stray light elimination module for eliminating stray light reflection in the fundus imaging unit.

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