JPH0542107A - Ophthalmic machine - Google Patents

Abstract

(57) [Summary] [Purpose] It is an object to provide an ophthalmologic machine capable of shortening the time for alignment operation. [Arrangement] An alignment optical system for aligning an optical axis O of a main optical system with a visual axis 4 of an eye to be inspected 13, and a corneal vertex P of the eye to be inspected 13.
Is different from the alignment optical system for setting the working distance W from the main optical system to the main optical system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an alignment optical system for aligning the optical axis of a main optical system with the visual axis of an eye to be inspected and for setting the distance from the corneal vertex of the eye to be inspected to the main optical system. The improvement of ophthalmic machines.

[0002]

2. Description of the Related Art Conventionally, an ophthalmologic machine provided with an alignment optical system for aligning an optical axis of a main optical system with a visual axis of an eye to be examined and for setting a distance from a corneal vertex of the eye to be examined to the main optical system. It has been known. For example, in a non-contact tonometer as an ophthalmologic machine, a pair of alignment optical systems are symmetrically provided on both sides of the optical axis of the main optical system. The pair of alignment optical systems irradiates the cornea with a parallel light beam, and forms a virtual image as a pair of alignment index images on the cornea by corneal mirror reflection of the parallel light beam.
The pair of alignment index images are displayed in an overlapping manner when the distance from the apex of the cornea to the tip of the main optical system, for example, the tip of the jet nozzle, is a normal working distance, and at the center of the cornea. The pair of index images i1 and i2 are displayed separately as shown in FIG. 6 when the distance from the apex of the cornea to the tip of the injection nozzle is not the normal working distance.
In addition, the midpoint (centroid position) of the pair of index images i1 and i2 is
When the optical axis of the main optical system is deviated from the visual axis of the subject's eye to the front, rear, left and right, it is deviated from the visual axis. The figure 6
In FIG. 1, 1 is a pupil of the eye to be inspected, 2 is a working distance permissible range mark indicating a permissible range of working distance, and 3 is a visual axis allowance indicating a permissible range of a matching relationship between the visual axis of the eye to be inspected and the optical axis of the main optical system. Range mark 4 indicates the visual axis.

[0003]

The alignment accuracy required for setting the distance from the apex of the cornea to the main optical system is higher than the alignment accuracy for aligning the visual axis of the eye to be inspected with the optical axis of the main optical system. Despite the large range, the same alignment operation that aligns the visual axis of the eye to be examined with the optical axis of the optical system of the conventional ophthalmologic machine and the alignment operation that sets the distance from the corneal apex to the main optical system Since the optical system is used, a pair of index images i are set in the visual axis allowable range mark 3 having a stricter allowable range.
The alignment operation is performed so that 1 and i2 exist.

However, it is necessary to adjust the working distance and perform the alignment operation so that the pair of index images i1 and i2 are present on the visual axis allowable range mark 3 having the stricter allowable range.
It requires considerable skill and difficulty, and there is a problem that the alignment operation takes time.

Therefore, an object of the present invention is to provide an ophthalmologic machine capable of shortening the time for alignment operation.

[0006]

In order to solve the above problems, an ophthalmologic machine according to the present invention has an alignment optical system for aligning an optical axis of a main optical system with a visual axis of an eye to be inspected, and a cornea of the eye to be inspected. The alignment optical system for setting the working distance from the apex to the main optical system is different.

[0007]

[Operation] According to the ophthalmologic machine of the present invention, the alignment operation for aligning the optical axis of the main optical system with the visual axis of the eye to be examined and the alignment operation for setting the working distance from the corneal apex to the main optical system are performed. This is done using separate alignment optics.

[0008]

1 is an anterior ocular segment observation optical system as a main optical system for observing an anterior ocular segment image including an eye to be examined. The anterior segment observation optical system 10 has an objective lens 11 and an imaging lens 12. On the optical axis O of the objective lens 11, a jet nozzle 14 for jetting an air pulse toward the subject's eye 13 is provided. The light flux forming the anterior segment image is focused on the CCD camera 16 via the objective lens 11, the half mirror 15, the half mirror 22, and the imaging lens 12. The half mirror 15 constitutes a part of an alignment optical system 17 for aligning a visual axis O'of the eye 5 to be examined with an optical axis O of the main optical system as shown in FIG. The alignment optical system 17 has an LED 18 as a light source, an opening 19 and a collimator lens 20. The LED 18 emits infrared light.

The collimator lens 20 collimates the infrared light of the LED 18 into a parallel light flux. The parallel light flux is reflected by the half mirror 15 toward the objective lens 11, passes through the inside of the injection nozzle 14, and is emitted toward the cornea 21 of the subject's eye 13. The parallel light flux is reflected by the cornea 21, and the reflected light flux is condensed by the objective lens 11. The reflected light flux is an imaging lens
12, led to the CCD camera 16 via the half mirror 22.
A part of the reflected light flux is reflected by the half mirror 22 and guided to the light receiving element 23, and the index image i3 for visual axis alignment alignment is formed on the CCD camera 16. The anterior ocular segment image and the index image i3 formed on the CCD camera 16 are input to a video signal processing circuit described later to be imaged. Its CCD camera 16
A reticle image forming the visual axis allowable range mark 3 is projected on the screen.

From the apex P of the cornea 21 to the tip Q of the injection nozzle 14.
An alignment optical system for setting the working distance W up to is provided separately from the alignment optical system 17. This alignment optical system has index projection optical systems 24 and 25. The index projection optical systems 24 and 25 are provided with an optical axis O of the objective lens 11.
Are arranged symmetrically. The index projection optical system 24 has an LED 26 as a light source. The index projection optical system 25 has an LED 27 as a light source. LED26 has, for example, a wavelength of 760n
Emits m infrared light. The infrared light emitted from the LED 26 is condensed by the condenser lens 28 and guided to the opening 29. The infrared light is focused on the center of the opening 29 and then guided to the dichroic mirror 30. The LED 27 emits infrared light having a wavelength of 860 nm, for example. The infrared light emitted from the LED 27 is condensed by the condenser lens 31 and guided to the opening 32. The infrared light is focused on the center of the opening 32 and then guided to the dichroic mirror 33. The dichroic mirror 30 reflects infrared light having a wavelength of 760 nm,
It has the property of transmitting infrared light with a wavelength of 860 nm. The dichroic mirror 33 reflects infrared light having a wavelength of 860 nm and has a wavelength of 760 nm.
It has a property of transmitting infrared light of nm. The infrared light having a wavelength of 760 nm reflected by the dichroic mirror 30 is guided to the objective lens 34. The infrared light with a wavelength of 860 nm reflected by the dichroic mirror 33 is guided to the objective lens 35. The objective lenses 34 and 35 face the cornea 21 of the subject's eye 13. The focal position of the objective lens 34 is at the center of the aperture 29. Objective lens
The focal position of 35 is in the center of the aperture 32. Objective lenses 34, 35
The infrared light guided to is converted into a parallel light flux by the objective lenses 34 and 35 and projected on the cornea 21. Objective lens 34
The parallel light flux projected by forms the index image i1 for working distance alignment based on the corneal mirror reflection. The parallel light beam projected by the objective lens 35 forms an index image i2 for working distance alignment based on corneal mirror reflection. The reflected light flux forming the index image i1 is guided to the objective lens 35 and is made a parallel light flux when the focal position of the objective lens 35 is at the formation position of the index image i1. Then, the parallel light flux is guided to the total reflection mirror 37 via the dichroic mirror 33 and the half mirror 36. Then, the direction is changed by the total reflection mirror 37, and the total reflection mirror is passed through the relay lens 38.
Guided to 39. The parallel light flux reflected by the total reflection mirror 39 is redirected by the total reflection mirror 40 and guided to the light receiving element 41.

The reflected light flux forming the index image i2 is guided to the objective lens 34 and is made a parallel light flux when the focal position of the objective lens 34 is at the point of the index image i2. The reflected light flux converted into the parallel light flux by the objective lens 34 passes through the dichroic mirror 30 and is guided to the total reflection mirror 42.
Is guided to the relay lens 43 by. The parallel light flux that has passed through the relay lens 43 is redirected by the total reflection mirrors 44 and 45 to form an image on the light receiving element 41. The index images i1 and i2 are matched in the light receiving element 41 when the distance from the corneal apex P of the eye to be inspected to the tip Q of the nozzle is a normal working distance and the corneal apex P coincides with the optical axis O. The image is formed, and in other cases, the image is formed separately.

The LEDs 18, 26, 27 are driven by drive circuits 46, 47, 48 as shown in FIG. This drive circuit 46 ~
48 is controlled by a control calculation unit 52 having a function described later. The LEDs 26 and 27 are alternately turned on and off as shown in FIG. The output of the light receiving element 41 is input to the signal processing circuit 49, and the output of the light receiving element 23 is input to the signal processing circuit 50.

The signal processing circuit 49 has a pair of index images i1 and i2.
The center of gravity position of is detected. The signal processing circuit 50 detects the barycentric position of the index image i3. The detection result is stored in the storage circuit 51. The detection data stored in the storage circuit 51 is input to the control calculation circuit 52. The control calculation circuit 52 calculates the distance between the centers of gravity of the pair of index images i1 and i2. The calculation time is repeated during the period t as shown in FIG.

The control arithmetic circuit 52 is a video signal processing circuit 53.
It also has a function of controlling the fluid discharge driving means 54. The output of the CCD camera 16 is input to the video signal processing circuit 53.
The output of the video signal processing circuit 53 is input to the display means 55.
As shown in FIG. 5, the display means 55 displays the pupil 1, the working distance allowable range mark 2, and the visual axis allowable range mark 3 as the anterior segment image.

The examiner indicates that the index image i3 is the visual axis allowable range mark 3
The optical axis O of the optical system is adjusted with respect to the visual axis O ′ so as to enter inside. On the other hand, the video signal processing circuit 53 displays the working distance W on the bar graph 56 'based on the calculation result of the control calculation unit 52. The working distance W is adjusted so that the shaded area of the bar graph 56 'is within the working distance range mark 2.

W'indicates that the working distance W is optimum.

The control arithmetic circuit 52 determines whether the working distance is within the allowable range, and also determines whether the visual axis of the eye 13 to be examined is within the visual axis allowable range mark 3 to determine the working distance W. When both the visual axis 4 and the visual axis 4 are set within the allowable range, the fluid discharge driving start signal is output to the fluid discharge driving means 54.
The fluid discharge driving means 54 automatically causes the injection nozzle 16 to
Initiate an air pulse towards 21. It should be noted that the air pulse can be emitted by a manual switch.

LED 26, condenser lens 28, aperture 29,
The dichroic mirror 30 and the objective lens 34 are provided for the cornea 21 to optically detect the deformation of the cornea due to the ejection of the air pulse.
It functions as a detection light projection optical system that projects the corneal deformation detection light toward. The cornea 21 is applanated by the jet of air pulses.

The reflected light beam due to the deformation of the cornea passes through the objective lens 35 and the dichroic mirror 33 and the half mirror 36.
Is guided to the condenser lens 56 and is focused on the light receiving element 57 by the condenser lens 56. The objective lens 35, the dichroic mirror 33, the half mirror 36, the condenser lens 56, and the light receiving element 57 constitute a detection light receiving optical system for receiving the reflection of the corneal deformation detection light by the cornea 21, and the light receiving element thereof when the deformation of the cornea 21 starts. The amount of light received by 57 increases. The intraocular pressure is measured according to a known procedure based on the increase in the amount of light received due to the deformation of the cornea 21.

[0020]

According to the non-contact tonometer of the present invention, the alignment operation for aligning the optical axis of the main optical system with the visual axis of the eye to be inspected and the working distance from the corneal apex of the eye to be inspected to the main optical system are set. Since we decided to perform the alignment operation separately, it is possible to avoid performing the alignment operation, which is difficult to perform strictly, in a strict tolerance range, and to shorten the alignment operation time. Therefore, it is possible to reduce the burden on both the examiner and the subject.

[Brief description of drawings]

FIG. 1 is a plan view of an optical system of an ophthalmologic machine according to the present invention.

FIG. 2 is a side view of the optical system shown in FIG.

FIG. 3 is a control block diagram of the ophthalmologic machine according to the present invention.

FIG. 4 is a timing chart of on / off control of an LED according to the present invention.

FIG. 5 is an explanatory diagram of an alignment display state according to the present invention.

FIG. 6 is an explanatory diagram of a conventional alignment display state.

[Explanation of symbols]

 4 optic axis 13 eye 17 alignment optical system 21 cornea 24, 25 index image projection optical system P corneal apex W working distance

Claims (1)

[Claims] 1. An alignment optical system for aligning an optical axis of a main optical system with a visual axis of an eye to be examined and an alignment optical system for setting a working distance from a corneal apex of the eye to the main optical system are different from each other. Characteristic ophthalmic machine.