JP2003000548A - Anterior ocular segment observation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anterior ocular segment observation system by which illuminating conditions are fixed and the surface portion of the anterior ocular segment or the like can be observed without making a subject feel dazzling. SOLUTION: This system is provided with an objective lens 6 having a photographing lens 7 and a ring-shaped illuminating lens 8 coaxially arranged around the photographing lens 7, an optical illuminating system 3, which has a light source 9, for irradiating an eye E to be examined with illuminating light from the light source 9, an optical observing system 4 having an imaging device 13 for receiving reflected light transmitted from the eye E through the photographing lens 7, and a parallel lens 10 arranged on the light source 9 on the side of the objective lens 6. The illuminating lens 8 is configured so as to converge the illuminating into form of ring so that mirror reflected light on the focal point of the photographing lens 7 can not be incident to the photographing lens 7. The parallel lens 10 is configured so as to make the light flux of illuminating light to the illuminating lens 8 into cylindrical parallel light along with an optical axis KL of the objective lens 6.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anterior segment observation apparatus. More specifically, for observing the state of the anterior segment by irradiating the anterior segment of the eye to be examined with illumination light from its front face, receiving reflected light to the front face of the anterior segment,
The present invention relates to an anterior segment observation device using a so-called indirect illumination method.

[0002]

2. Description of the Related Art Conventionally, in the field of ophthalmology, a slit lamp is used to observe the anterior segment of the eye by an indirect illumination method. The slit lamp is configured such that an illumination device that emits slit light and a microscope work together. Generally, by adjusting the diopter, the focus of the illumination and the focus of the microscope match at one point. Therefore, once the focus is adjusted, it is possible to irradiate an arbitrary observation site (referred to as an inspected part) with the slit light and observe it by operating the handle or the like. By using this slit lamp, it is possible to perform observation without directly irradiating the subject portion of the subject eye with slit light. By this illumination, the test portion is raised, and it is possible to emphasize and observe a minute change or a weak contrast image that is difficult to express by direct illumination. Further, with the slit lamp, the crossing angle formed by the optical axis of the observation optical system (shooting optical system) and the optical axis of the illumination optical system can be changed.

However, the direction of change of the intersection angle is only in the left-right direction. The optical axis of the illumination optical system (illumination optical axis) cannot be tilted vertically or obliquely with respect to the optical axis of the observation optical system (observation optical axis). Further, the indirect illumination method, particularly the dark field illumination method, requires delicate adjustment of the observation optical axis and the illumination optical axis, which may take time. If the adjustment takes too long, the burden on the eye to be inspected becomes large and the natural state cannot be observed.

Further, when observing the cornea, the illumination light may reach the macula of the fundus of the subject's eye, causing the subject to be dazzled.
Stable observation may not be performed. The macula refers to a range of about 12 degrees in visual angle, centered on a portion of the retina where the photoreceptor cell density is extremely high.

The present invention has been made in order to solve the above problems, and the illumination conditions are kept constant by changing the part to be inspected in the anterior segment of the eye, and the subject is not dazzled. An object of the present invention is to provide an anterior ocular segment observation device capable of observing the tear film, mucin layer, corneal epithelium and the like of the eye.

[0006]

An anterior segment observation apparatus according to the present invention comprises an objective lens having a photographing lens and a ring-shaped illumination lens coaxially arranged around the photographing lens,
An illumination optical system having an illumination light source, an illumination optical system for irradiating the eye to be inspected with illumination light from the light source, and an observation optical system having a light receiving section for receiving the reflected light from the eye to be inspected that has passed through the photographing lens The illumination lens is configured to converge the illumination light in a ring shape so that specular reflection light at the focal point of the imaging lens does not enter the imaging lens.

According to such an anterior segment observation apparatus, when the eye to be inspected is irradiated with the illumination light through the illumination lens in the objective lens, the illumination is inclined from the periphery of the observation optical axis substantially perpendicular to the anterior segment surface. Light is applied to the test area. Therefore, even if the subject has a spherical surface such as an eyeball, the illumination condition becomes constant, and stable observation by scattered light becomes possible. Further, since the illumination light has a ring shape, even when observing the cornea of the subject's eye, the illumination light reaching the fundus exhibits a ring shape and does not illuminate the macula, so the subject may be dazzled. Absent.

An illumination light blocking member is provided on the light source side of the illumination lens in the illumination optical system, and the illumination light blocking member is configured to selectively transmit at least a part of the illumination light beam. The anterior ocular segment observing device is preferable. This is because the test portion can be observed by the reflected light scattered by the illumination light from the arbitrarily selected direction. Since it is possible to observe the same inspected portion with illumination light from a plurality of different directions, it becomes easy to detect minute unevenness of the inspected portion.

Further, the illumination light shielding member has a light shielding plate rotatable about the optical axis of the illumination optical system, and a light transmitting portion is formed on at least a part of the light shielding plate. An eye observation device is preferred. This is because the above-described optional mechanism for the illumination direction can be realized with a simple configuration. Further, by providing the light transmitting portions at a plurality of positions, it is possible to illuminate the test portion from both sides, for example, so that the test portion that cannot be obtained by illuminating from one direction or illuminating all around Sometimes you can get a statue of. Moreover, by making the light shield plate rotatable,
The most effective illumination can be easily found according to the state of the part to be inspected. The light transmitting portion can be formed, for example, by forming the light shielding plate from a transparent plate and leaving the portion serving as the light transmitting portion opaque at the portion that shields light. Alternatively, for example, the light shielding plate may be formed of an opaque plate, and the portion serving as the light transmitting portion may be cut out.

Further, in the anterior ocular segment observation apparatus in which a polarizer is disposed on the light source side of the illumination lens in the illumination optical system, the polarization component varies depending on the state of the interface that reflects the illumination light in the subject. Join. Therefore, by distinguishing this polarized light, it is possible to selectively observe the reflecting surface of the subject. That is, not only when the contact lens is worn, but also when there is an overlapping of reflecting surfaces such as the interface between the tear film and the corneal epithelium, the reflected light on each surface can be selectively extracted.

A collimating lens is provided on the objective lens side of the light source, and the collimating lens transforms the luminous flux of the illumination light to the illumination lens into cylindrical parallel light along the optical axis of the objective lens. The anterior ocular segment observing device configured as described above is preferable. By doing so, the degree of freedom in arranging the illumination light source and the observation optical system is improved, and accurate illumination light is easily incident on the illumination lens.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The anterior segment observation apparatus of the present invention will be described based on the embodiments shown in the accompanying drawings.

FIG. 1 is an optical path diagram showing an embodiment of the anterior segment observation apparatus of the present invention.

The anterior segment observation apparatus 1 shown in FIG.
The image pickup system 2 is arranged on a machine frame 2a that can be moved in the Z direction that moves forward and backward toward, and in the X direction and the Y direction that are perpendicular to the Z direction and are perpendicular to each other.

The photographing system 2 is an illumination optical system 3 for illuminating the anterior segment of the subject's eye E with illumination light from the front thereof.
And an observation optical system 4 for receiving reflected light from the anterior segment surface of the eye E, and a fixation optical system 5 for keeping the direction of the eye E constant by making the eye E fixate a certain index.
It has and. Further, although not shown, an alignment optical system for irradiating the alignment index light for observation optical axis alignment (alignment) from the front toward the anterior segment of the eye E, and for imaging the cornea reflected light, A focusing optical system for matching the focusing point of the observation optical system 4 with the inspected portion is provided.

The photographing system 2 has an objective lens 6 at a position facing the eye to be examined. As shown in the figure, the objective lens 6 has a photographing lens 7 arranged in the center and a ring-shaped illumination lens 8 arranged coaxially around the photographing lens 7. Therefore, the optical axes KL of both lenses 7 and 8 coincide with each other.
The objective lens 6 is arranged on the common optical axis of the illumination optical system 3 and the observation optical system 4. At the boundary between the taking lens 7 and the illumination lens 8, a cylindrical light shielding tube 6a that shields light is arranged. The light shielding tube 6a extends to the position of the polarizer 12 along the optical axis KL.

The illumination optical system 3 has a light source 9 for anterior ocular segment illumination. Further, along the illumination optical axis L from the light source 9 toward the eye E to be examined, the collimating lens 10 and the illumination light blocking member 1 are provided.
1, the polarizer 12, and the illumination lens 8 are arranged in that order. As shown in FIG. 3, the shielding member 11 has a central portion corresponding to the taking lens 7 as a first shielding portion 21. The first shielding portion 21 is a portion that shields the illumination light so that the illumination light does not enter the photographing lens 7 from the back side. The second shield 22 that is partially formed around the first shield 21
Will be described later.

The observing optical system 4 has an image pickup device 13, and an observation optical axis K from the image pickup device 13 in the direction of the eye E to be examined.
An imaging lens 14, an analyzer 15, a mirror 16, and the taking lens 7 are arranged in that order along the. The optical axis K from the mirror 16 to the taking lens 7 is the optical axis KL common to the optical axis L of the illumination optical system 3. A monitor 17 is connected to the image sensor 13.

The fixation optical system 5 has a fixation lamp 18.
A focusing lens 18 and a mirror 19 are arranged in this order from the fixation lamp 18 toward the objective lens 6 along the fixation optical axis W. The optical axis W from the mirror 16 to the objective lens 6 coincides with the optical axis KL.

When using the apparatus 1, the apparatus 1 must be aligned with the eye E before the observation operation (imaging operation) is started. Normally, an inspector manually performs this alignment, but since the present apparatus 1 is provided with the alignment optical system and the focusing optical system for automatically performing accurate alignment and focusing, these functions are provided. Will be briefly described.

First, the subject fixes his / her face by a not-shown chin rest or the like, and further fixes the illuminated fixation lamp 18. By doing so, the eye E is fixed in a fixed direction. In this state, the imaging system 2 is aligned with the subject portion of the subject's eye E by an alignment optical system and a focusing optical system (not shown).

Specifically, near-infrared light from an alignment light source of an alignment optical system (not shown) is applied to the anterior segment of the eye E from the front side. Furthermore, a bright spot (Purkinje image) which is a reflection image of this alignment light on the cornea.
Is sent to a television camera (not shown). On the basis of this Purkinje image, the machine frame is moved in the X-Y directions (two directions perpendicular to the optical axis KL) to observe the observation optical axis K.
Is aligned with the apex of the cornea. This is the alignment operation. The corneal apex is the closest point to the device 1 of the eye E to be examined.

Further, for focusing, the photographing system 2 is set to Z with respect to the subject.
The position is aligned in the direction (the optical axis KL direction). A focusing optical system (not shown) includes a focusing lamp and a position sensor. The optical axis of the focusing lamp that goes to the eye to be examined,
The optical axis of the position sensor facing the eye to be inspected intersects on the optical axis KL. The focal point of the observation optical system 4, that is, the point at a position conjugate with the light receiving surface of the image pickup device 13 is set to the focal point. Then, by moving the device 1 in the Z direction, the position sensor detects the focus detection light (near infrared light) from the focusing lamp when the subject portion reaches the intersection (focus point). Has been

These alignments are performed as a preparation operation for the observation operation. Generally, the alignment operation and the focusing operation are performed in parallel.

Next, regarding the observation operation, the examiner looks at the subject's eye and the objective lens 6 from the side and positions the optical axis KL at the apex of the subject's eye in an approximate positional relationship. Then, while watching the monitor 17, the imaging system 2 is advanced toward the eye E to be inspected. Then, the screen of the monitor 17 becomes white due to the corneal reflection of the illumination light. When brought closer, ring-shaped illumination causes a black area with no reflection to appear in the central area. While keeping this black portion in the center of the screen, the photographing system 2 is brought closer to observe.

Looking at this observation operation with respect to the photographing system 2,
First, the illumination light from the illumination light source 9 passes through the collimating lens 10, the shielding member 11, and the polarizer 12 and reaches the illumination lens 7.
The illumination light is not incident on the taking lens 7 by the shielding member 11 but is transmitted only through the illumination lens 8 to be a ring-shaped light beam which is converged and incident on the eye E to be inspected. Therefore, the illumination light is applied to the eye E from the front along the illumination optical axis L,
When looking at the vicinity of the portion to be inspected, the illumination light is obliquely incident. Then, the illumination light specularly reflected on the anterior segment surface of the eye E to be examined travels to the opposite side across the optical axis KL and reaches the illumination lens 8. Therefore, the specularly reflected light at the anterior segment does not enter the taking lens 7. However, since the surface of the anterior segment is not a perfectly smooth mirror surface, a small amount of illumination light is diffusely reflected and enters the taking lens 6. This irregularly reflected light that has passed through the taking lens 6 is reflected by the mirror 16, passes through the analyzer 15 and the imaging lens 14, and is received by the image pickup device 13. Then, it is displayed on the monitor 17 as an image showing the state of the anterior segment surface in detail. Here, normally, the focus of the illumination lens 8 and the focus of the photographing lens 7 are matched. In other words, the position of the taking lens 7 which is conjugate with the light receiving surface of the image sensor 13 is made to coincide with the position of the illumination lens 8 which is conjugated with the light source 9. This position is called the focus of the objective lens 6.

Since this image is an image obtained by scattered light, it is possible to emphasize and observe a minute change or an image with weak contrast that is difficult to express by direct illumination. For example, it is possible to effectively observe the condition of tears, the condition of oil and fat layer, the condition of mucin layer, the condition of corneal epithelium surface, the condition of crystalline lens, etc., such as dirt, dust and scratches on the corneal surface. Also, when the subject is an eyeball, the surface of the subject is spherical, but since the illumination light is emitted from around the subject, the illumination direction changes even when the observation site is changed. However, the illumination conditions do not change, and stable observation is possible.

FIG. 2 shows the state of the illumination light transmitted through the illumination lens 8. In this figure, the light flux is colored gray for easy understanding. FIG. 2A shows the traveling direction of the illumination light. FIG. 2B is B1- of FIG.
It is a B1 line sectional view, a B2-B2 line sectional view, and a B3-B3 line sectional view, and has shown the range of the light flux in the field perpendicular to optical axis KL. That is, the inspected part is at the B1-B1 line position,
The range of the light flux at each of the B2-B2 line position and the B3-B3 line position is shown. 2 (c) is shown in FIG.
(A) B1-B1 line position, B2-B2 line position and B
It is the graph which showed the light quantity in 3-B3 line position. B
2-B2 line position is the focal point of the objective lens, and B1-
The B1 line position is a position separated from the focus of the objective lens 6 by about 2 mm toward the eye E, and the B3-B3 line position is a position separated from the focus of the objective lens 6 by about 1.5 mm toward the objective lens 6.

As shown in FIG. 2B, when the portion to be inspected is located at the line B2-B2, the specularly reflected light at the portion to be inspected is the portion of the illumination lens 8 on the opposite side of the optical axis KL. Is incident on the image pickup element 1 and the part with diffused reflection light is incident on the taking lens 7.
Up to 3. When the part to be inspected is located at the line B1-B1 position,
Further, when positioned at the line B3-B3, a small amount of specular reflected light on the outer peripheral portion of the subject is incident on the vicinity of the outer periphery of the photographing lens 7, and similarly diffused reflected light on the outer peripheral portion of the subject is also photographed. It is incident on the lens 7. Good observation is possible even within this range. That is, useful information may be obtained not only by the dark-field illumination unit but also by observation in the vicinity of the boundary with the specular reflection unit or at the specular reflection unit. This is possible with a slight misalignment from the apex of the cornea.

The fundus of the subject's eye (not shown) is present on the left side in FIG. 2 (a). As shown in the figure, since the illumination light entering the eye to be inspected has a ring shape, it does not normally irradiate the macula, so that the subject is relatively free from glare during observation.

FIG. 3 shows three kinds of the shielding members 11 described above. Each of the shield members 11a, 11b, 11c is made of a transparent disc member, and the circular first shield portion 21 is formed in the center of the shield member 11 concentrically with the outer shape of the shield member 11 as described above. . The illumination light is the first shielding part 21.
Since it cannot pass through, the illumination light is prevented from entering the taking lens 7. Shielding member 11 of FIG.
In a, a transparent ring-shaped light transmitting portion 20 is formed around the first shielding portion 21.
The second shield 22 is not formed at 0. The shielding member 11b shown in FIG. 3B includes one second shielding portion 2 in the light transmitting portion 20.
Only 2 are formed. The shielding member 11c of FIG. 3C is one in which two second shielding portions 22 are formed on the light transmitting portion 20. Of course, three or more second shields 2
2 may be formed.

If the shielding members 11b and 11c shown in FIGS. 3 (b) and 3 (c) are used, the illumination light will enter only a part of the ring-shaped illumination lens 8. As a result, the subject light is irradiated with the illumination light from a specific direction. Further, the centers of these shielding members 11b and 11c coincide with the illumination optical axis L, and they are rotated around the illumination optical axis L. By doing so, it is possible to continuously change the irradiation direction of the illumination light to the test portion. By doing this, it is possible to observe the reflected light in which the state of fine irregularities of the test part is different, and moreover, by observing while rotating, it is possible to express the three-dimensional shape of the fine structure of the observation target. It will be possible. Therefore, it is possible to detect even the state of the portion to be inspected, which cannot be detected by the reflected image of the illumination light from only one direction. Moreover, it becomes easy to find the most effective illumination according to the state of the part to be inspected. When actually observing, the observation is performed while rotating the shielding member 11 slowly automatically or manually, and the rotation is stopped if necessary.

As shown in FIG. 1, this embodiment includes a polarizer 12 and an analyzer 15. Therefore, a polarization component is added depending on the state of the interface that reflects the illumination light in the test portion. By distinguishing this polarized light, it is possible to selectively observe the reflecting surface of the subject. That is, not only when wearing contact lenses,
When there are overlapping reflective surfaces such as the interface between the tear film and the corneal epithelium, the reflected light on each surface can be selectively extracted. For example, it becomes possible to know the state of scratches, stains, and tears on the surface of the eye to be inspected while wearing the contact lens. In addition, the so-called soft contact lens fitting state and the strain state of the soft contact lens can also be observed. Furthermore, the appearance of the epithelial surface when a so-called hard contact lens is attached can be observed. In addition, the corneal stroma layer and nerves will also be observed. Although the effect is slightly reduced, the analyzer 15 may be removed and only the polarizer may be used.

In the above embodiment, the illumination optical axis L is formed in a straight line from the light source 9 to the objective lens 6 and the observation optical axis K is bent halfway by the mirror 16, but the present invention is not limited to such a configuration. For example, for the observation optical system 4, the optical axis K from the image pickup device 13 to the objective lens 6 should be aligned, and for the illumination optical system 3, a ring-shaped mirror corresponding to the illumination lens should be installed at an angle to the optical axis KL. The illumination optical axis L may be bent by.

Also, the use of the collimating lens 10 is not essential to the invention. However, by using the collimating lens 12 to collimate the illumination light reaching the illumination lens 8, the above-described advantages can be obtained.

[0036]

According to the anterior segment observation apparatus of the present invention, the illumination condition becomes constant by changing the examined part in the anterior segment, and the anterior segment does not make the subject feel dazzling. Can observe the tear film, mucin layer, corneal epithelium, etc.

[Brief description of drawings]

FIG. 1 is an optical path diagram showing an embodiment of an anterior segment observation apparatus of the present invention.

2 (a) is a schematic view showing a traveling state of illumination light near an objective lens in the apparatus of FIG.
2B is a sectional view taken along line B1-B1 of FIG.
2-B2 line sectional view and B3-B3 line sectional view showing the range of the luminous flux in a plane perpendicular to the optical axis KL,
FIG. 2C is a position of line B1-B1 of FIG.
It is a graph which showed the light quantity in a 2 line position and a B3-B3 line position.

3 (a), FIG. 3 (b), and FIG. 3 (c) are plan views showing examples of a shielding member in the anterior segment observation apparatus of FIG.

[Explanation of symbols]

1 Anterior segment observation device 2 Shooting system 2a Machine frame 3 Illumination optical system 4 Observation optical system 5 Fixation optical system 6 Objective lens 6a Light shielding tube 7 Shooting lens 8 illumination lens 9 light sources 10 Parallelizing lens 11 11a, 11b, 11c Shielding member 12 Polarizer 13 Image sensor 14 Imaging lens 15 Analyzer 16 mirror 17 monitors 18 Fixing light 19 mirror 20 Light transmission part 21 First shield 22 Second shield K, L, KL, W optical axis E eye to be examined

Claims (5)

[Claims] 1. An objective lens having a photographing lens and a ring-shaped illumination lens arranged coaxially around the photographing lens, and an illumination light source, and the illumination light from the light source is applied to an eye to be examined. And an observation optical system having a light receiving part for receiving the reflected light from the eye to be inspected that has passed through the taking lens, and the illumination lens is a specular reflected light at the focal point of the taking lens. An anterior segment observation apparatus configured to converge the illumination light in a ring shape so that the light does not enter the photographing lens. 2. An illumination light blocking member is provided on the light source side of the illumination lens in the illumination optical system, and the illumination light blocking member is configured to selectively transmit at least a part of the illumination light beam. The anterior ocular segment observation device according to claim 1. 3. The illumination light shielding member has a light shielding plate rotatable about the optical axis of the illumination optical system, and a light transmitting portion is formed on at least a part of the light shielding plate. Item 2. The anterior segment observation device according to item 2. 4. The anterior segment observation apparatus according to claim 1, wherein a polarizer is arranged on the light source side of the illumination lens in the illumination optical system. 5. A collimating lens is provided on the objective lens side of the light source, and the collimating lens transforms the luminous flux of illumination light to the illumination lens into cylindrical parallel light along the optical axis of the objective lens. The anterior ocular segment observation device according to claim 1, which is configured to: