CN114145706A - Ophthalmologic measurement optical system - Google Patents

Abstract

The invention discloses an ophthalmologic measuring optical system, which is used for measuring the vertex curvature of a cornea of a tested human eye and comprises an eye objective lens, an imaging lens, a camera device and a luminous light source assembly, wherein the luminous light source assembly, the imaging lens and the camera device are respectively and sequentially arranged on one side of the eye objective lens, which is far away from the tested human eye, the luminous light source assembly comprises a plurality of luminous light sources, and light emitted by the luminous light sources is transmitted by the eye objective lens, then enters the tested human eye, is reflected by the cornea of the tested human eye, then passes through the eye objective lens again, and is received by the camera device after being transmitted by the imaging lens. The ophthalmologic measurement optical system provided by the invention improves the measurement precision of the corneal curvature.

Description

Ophthalmologic measurement optical system

Technical Field

The present invention relates to an ophthalmic optical inspection apparatus, and more particularly, to an ophthalmic measurement optical system.

Background

Corneal vertex curvature is an important optical parameter for the human eye. The measurement of the corneal vertex curvature has important reference significance for keratoconus, LASIK (excimer laser surgery), cataract surgery, juvenile myopia prevention and control and the like. The existing products or instruments also comprise corneal vertex curvature measuring technologies, such as a corneal curvature instrument, a corneal topography instrument, an ophthalmic optical biological measuring instrument and the like. The principles used by different instruments are different. For example, a corneal topographer uses Placido's disk principle to measure the curvature distribution over a large area of the cornea. The ophthalmic optical biological measuring instrument can provide the corneal vertex curvature, see chinese patent documents CN101596096A and CN 111557637A; the light emitted by a plurality of light-emitting light sources distributed on the periphery of the ocular objective lens is reflected by the cornea and then is received by the camera light path. The curvature of the corneal vertex is derived by measuring the relative position of the plurality of light source images along with the change of the corneal curvature of the eye to be measured. Compared with the corneal curvature topographic map measuring technology based on the Placido's disk principle, the corneal vertex curvature measuring technology has the advantages of few measuring data points, high speed, simple structure and the like.

In the existing corneal vertex curvature measuring scheme, a plurality of light-emitting sources are distributed on the periphery of an objective lens, and corneal reflection images of the light-emitting sources are obtained, so that the central curvature of the cornea is obtained. This technique often requires that the source of illumination be reflected off the cornea with a small distance from the apex of the cornea, typically 3mm or 2mm or even 1mm less. However, for an objective lens with a large numerical aperture, the aperture is large and the working distance is short. If the plurality of light-emitting sources are distributed on the periphery of the objective lens, the light beams emitted by the light-emitting sources and reflected by the cornea are difficult to be received by the camera system behind the objective lens (the other side of the objective lens opposite to the eye to be measured is called as the back side). Or the light beam reflected by the cornea can be received by the camera system behind the objective lens, but the light beam reflection point on the cornea is often far away from the corneal vertex, exceeding 1mm, and even exceeding 2mm or 3 mm. Even if the imaging system obtains a plurality of light source images reflected by the cornea, the data of the curvature of the corneal vertex obtained by estimating the light beam reflection point on the cornea is often unreliable because the light beam reflection point is far away from the corneal vertex.

The above background disclosure is only for the purpose of assisting understanding of the concept and technical solution of the present invention and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides an optical system for ophthalmic measurement, which improves the measurement accuracy of corneal curvature.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention discloses an ophthalmologic measuring optical system, which is used for measuring the vertex curvature of a cornea of a tested human eye and comprises an eye objective lens, an imaging lens, a camera device and a luminous light source assembly, wherein the luminous light source assembly, the imaging lens and the camera device are respectively and sequentially arranged on one side of the eye objective lens, which is far away from the tested human eye, the luminous light source assembly comprises a plurality of luminous light sources, and light emitted by the luminous light sources is transmitted by the eye objective lens, then enters the tested human eye, is reflected by the cornea of the tested human eye, then passes through the eye objective lens again, and is received by the camera device after being transmitted by the imaging lens.

Preferably, the light source assembly further includes a plurality of collecting lenses, and the plurality of collecting lenses correspond to the plurality of light sources one to one, so that light emitted by each of the light sources is collected by the corresponding collecting lens before transmitting through the objective lens.

Preferably, the ophthalmology measuring optical system further comprises a diaphragm, the diaphragm is located between the eye objective and the imaging mirror, and a plurality of lights emitted by the light-emitting light source are transmitted through the eye objective and then incident on the eye of the tested person, and after being reflected by the cornea of the eye of the tested person, the lights pass through the eye objective again and then pass through the diaphragm and then transmit the imaging mirror.

Preferably, a plurality of the light-emitting light sources and the respective condenser lenses are arranged in a circumferential direction of the diaphragm. The imaging optical path can be effectively avoided.

Preferably, the diaphragm is in the image-side focal plane of the objective lens. The iris of the eye to be measured is positioned on the object focal plane of the ocular objective, and at the moment, if the eye to be measured deviates from the required working position back and forth along the optical axis, the positions of the images of the plurality of light-emitting light sources still do not change, so that the calculation is facilitated, and the measurement precision is improved.

Preferably, the diaphragm is located in an object focal plane of the imaging mirror, and the camera device is located in an image focal plane of the imaging mirror. In the scheme of simultaneously adopting the object space telecentric light path principle and the image space telecentric light path principle, the measurement of the positions of the images of the plurality of light-emitting sources cannot be influenced by slight deviation of the eyes of the tested person and the camera device from the set working positions, and the measurement precision is further improved.

Preferably, the number of the plurality of light emitting sources is greater than or equal to 3.

Preferably, a plurality of the light emitting sources and the corresponding condenser lenses are arranged at equal intervals in a circumferential direction of the diaphragm.

Compared with the prior art, the invention has the beneficial effects that: the ophthalmologic measuring optical system provided by the invention can simply and conveniently realize the measurement of the vertex curvature of the cornea of human eyes, and is particularly suitable for ophthalmologic measuring equipment which has short working distance and large aperture of an eye-catching objective lens. In the invention, a plurality of light-emitting sources are positioned behind the ocular objective, the light emitted by the light-emitting sources is reflected by the cornea, and the distance between the light beam reflection point on the cornea and the vertex of the cornea is not influenced by the increase of the numerical aperture of the ocular objective; in this case, it is easy to realize that the distance between the reflection point of the light beam on the cornea and the vertex of the cornea is less than or equal to 3mm or 2mm, or even less than or equal to 1 mm. Therefore, even if the numerical aperture of the eye objective lens of the ophthalmologic measurement equipment is large, such as a color fundus camera system and the like, the problem that the cornea vertex curvature of the human eye cannot be measured by the ophthalmologic measurement optical system of the eye objective lens with the large numerical aperture can be still solved.

Drawings

Fig. 1 is an optical path diagram of an ophthalmic measurement optical system according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of an arrangement of a plurality of light sources and diaphragms;

FIG. 3 is an optical path diagram of a prior art ophthalmic measurement optical system;

FIG. 4 is a schematic diagram of a prior art arrangement of multiple light sources and an eye objective;

fig. 5 is a schematic view of the ophthalmic measurement optical system in fig. 3.

Detailed Description

The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. In addition, the connection may be for either a fixed function or a circuit/signal communication function.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

As shown in fig. 1, a preferred embodiment of the present invention discloses an ophthalmologic measurement optical system for measuring the curvature of the corneal vertex of a human eye to be measured, which includes an objective lens 101, a diaphragm 102, an imaging lens 103, an imaging device 104, a plurality of light sources and a plurality of condensing lenses, wherein the diaphragm 102 and the plurality of condensing lenses are respectively disposed between the objective lens 101 and the plurality of light sources, and the imaging lens 103 and the imaging device 104 are sequentially disposed behind the plurality of light sources (the direction away from the eye to be measured is referred to as "rear" in the present invention).

The light emitted by a plurality of light-emitting sources (including the light-emitting sources 2011-2016) distributed behind the eye objective 101 passes through a condenser (including the condenser 2021-2026), then is transmitted through the eye objective 101, enters the eye E to be tested, is reflected by the cornea Ec of the eye to be tested, and then returns, passes through the eye objective 101, passes through the aperture stop 102, and is received by the camera device 104 after passing through the imaging lens 103.

In the preferred embodiment, the principle of telecentric optical path at object space is adopted, so that the iris Ei of the eye to be measured is in the focal plane at object space of the objective lens 101, and the diaphragm 102 is in the focal plane at image space of the objective lens 101. At this time, if the human eye E deviates from the desired operating position back and forth along the optical axis L1, the positions of the images with respect to the plurality of light-emitting light sources do not change. This further facilitates the simplification of the calculation and improves the measurement accuracy.

In some embodiments, if the object-side telecentric optical path principle is not adopted, the positions of the images of the plurality of light-emitting sources may change when the eye E to be measured moves back and forth along the optical axis L1. The system needs to accurately obtain the position of the cornea to be measured, and then the change of the positions of the images of the plurality of light-emitting light sources can be corrected, and the curvature of the vertex of the cornea can be calculated. Compared with an object space telecentric scheme, the scheme without adopting the object space telecentric optical path principle has the advantages of complex system (corneal vertex distance measurement needs to be introduced), complex calculation, easy introduction of errors and reduced corneal vertex curvature measurement precision.

In a further more preferred embodiment, the imaging optical path also adopts a telecentric optical path principle, namely a double telecentric imaging optical path principle is adopted; at the moment, the iris Ei of the eye to be detected is positioned on the object focal plane of the eye objective 101, and the diaphragm 102 is positioned on the image focal plane of the eye objective 101; and the diaphragm 102 is in the object-side focal plane of the imaging mirror 103 and the camera device 104 is in the image-side focal plane of the imaging mirror 103. In this embodiment, measurement of the positions of the images of the plurality of light-emitting sources is not affected by slight deviation of human eye E and imaging device 104 from the set operating positions.

In the invention, a plurality of light-emitting sources (including the light-emitting sources 2011-2016) are positioned behind the ocular objective 101, the light emitted by the light-emitting sources (including the light-emitting sources 2011-2016) is reflected by the cornea, and the distance h between a light beam reflection point F2011 on the cornea and a corneal vertex Ec0 is not influenced by the increase of the numerical aperture of the ocular objective 101; at this time, the distance h between the light beam reflection point F2011 on the cornea and the vertex of the cornea is easy to be smaller than or equal to 3mm or 2mm, even smaller than or equal to 1 mm.

As shown in FIG. 2, the light sources (including 2011-2016) are distributed at the positions corresponding to the aperture 102; in addition, in order to effectively avoid the imaging optical path, the plurality of light sources (including the light sources 2011-2016) are preferably distributed around the periphery of the aperture 102. In a further embodiment, the number of the plurality of light sources is greater than or equal to 3, and in this embodiment, the number of the plurality of light sources is schematically 6. The optics in the optical path are only illustrative, such as the objective lens 101 and the imaging lens 103, which may each be in the form of a single lens or a combination of lenses.

As shown in fig. 3 and 4, the diagram is a structural diagram of an ophthalmic measurement optical system in the prior art, and the diagram includes an eye E to be measured, an iris Ei of the eye to be measured, a cornea Ec of the eye to be measured, a corneal vertex Ec0 of the eye to be measured, an objective lens Y101, a camera system Y10, a main optical axis YL1, a plurality of light-emitting light sources Y2011-Y2016, a light beam reflection point YF2011 on the cornea, and a distance h between the light beam reflection point YF2011 on the cornea and the corneal vertex; the periphery of the objective lens Y101 is distributed with a plurality of light-emitting sources Y2011-Y2016, the light-emitting sources Y2011-Y2016 emit light and are reflected by a cornea Ec, and a reflected light beam passes through the objective lens Y101 and is received by the camera system Y10, so that images of the light-emitting sources Y2011-Y2016 are obtained. The distance h between the light beam reflection point YF2011 on the cornea and the vertex of the cornea is often required to be not too large, and is usually less than or equal to 3mm or 2mm, or even less than or equal to 1 mm. Due to the change of the corneal shape curvature, the relative positions of the images of the plurality of light-emitting sources Y2011-Y2016 are changed. The corneal vertex curvature can be derived from the images of the plurality of light-emitting sources Y2011-Y2016.

The position distribution of the plurality of light-emitting sources Y2011-Y2016 relative to the objective lens Y101 is shown in fig. 4, and the plurality of light-emitting sources Y2011-Y2016 are distributed outside the circumference of the objective lens Y101. When the numerical aperture of the objective lens Y101 is increased, the relative caliber of the objective lens is increased, and the working distance is reduced; when a plurality of light-emitting light sources Y2011-Y2016 are reflected by the cornea Ec, if the reflected light beams can be received by the camera system Y10 through the ocular objective lens Y101, the distance h2 between the light beam reflection point YF2011 on the cornea and the vertex of the cornea is often larger, and the measured curvature of the vertex of the cornea is not accurate enough; or when the distance h between the light beam reflection point YF2011 on the cornea and the vertex of the cornea is small, the reflected light beam cannot be received by the imaging system Y10 behind the objective lens Y101, as shown in fig. 5.

Through the comparison, in the prior art, for a large-numerical-aperture ocular objective lens, the measured curvature of the vertex of the cornea is not accurate enough, and when the distance between the light beam reflection point on the cornea and the vertex of the cornea is small, the reflected light beam cannot be received by a camera system behind the ocular objective lens; the preferred embodiment of the invention provides the large-numerical-aperture ocular objective lens for measuring the corneal vertex curvature, and further combines a telecentric measurement technology to improve the corneal curvature measurement precision.

It should be noted that the ophthalmic measurement optical system according to the preferred embodiment of the present invention is also applicable to small numerical aperture objective lenses, and has a wide applicability.

The background of the invention may contain background information related to the problem or environment of the present invention rather than the prior art described by others. Accordingly, the inclusion in the background section is not an admission of prior art by the applicant.

The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by the appended claims.

Claims (8)

1. The utility model provides an ophthalmology optical system for measure and survey human eye cornea summit camber, its characterized in that, including the objective lens, image forming mirror, camera device and luminous light source subassembly, wherein luminous light source subassembly the image forming mirror with camera device set gradually respectively in the objective lens is kept away from survey one side of people's eye, luminous light source subassembly includes a plurality of luminescent light source, and is a plurality of the light transmission that luminescent light source sent incides behind the objective lens to survey human eye, and the warp behind the cornea reflection of people's eye, pass through again the objective lens, and the transmission quilt behind the image forming mirror camera device receives.

2. An ophthalmic measurement optical system according to claim 1, wherein the illumination source assembly further includes a plurality of collecting mirrors, and the plurality of collecting mirrors are in one-to-one correspondence with the plurality of illumination sources, so that light emitted from each of the illumination sources is collected by the corresponding collecting mirror before being transmitted through the objective lens.

3. The ophthalmic-measuring optical system of claim 2, further comprising a diaphragm, the diaphragm being located between the objective lens and the imaging mirror, wherein light emitted from the plurality of light-emitting light sources is transmitted through the objective lens, then is incident on the eye of the human subject, is reflected by the cornea of the eye of the human subject, passes through the diaphragm after passing through the objective lens again, and then is transmitted through the imaging mirror.

4. An ophthalmic-measurement optical system according to claim 3, characterized in that a plurality of the luminescent light sources and the respective condenser lenses are arranged in a circumferential direction of the diaphragm.

5. An ophthalmic measurement optical system according to claim 3, characterised in that the diaphragm is in the image-wise focal plane of the objective lens.

6. An ophthalmic measuring optical system according to any one of claims 3 to 5, characterized in that the diaphragm is in the object-side focal plane of the imaging mirror and the camera device is in the image-side focal plane of the imaging mirror.

7. An ophthalmic measuring optical system according to claim 1, characterized in that the number of the light-emitting sources is greater than or equal to 3.

8. An ophthalmic-measurement optical system according to claim 4, characterized in that a plurality of the luminescent light sources and the respective condenser lenses are arranged equidistantly in a circumferential direction of the diaphragm.

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