JP2002253513A - Ophthalmologic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily conduct measurement even to a subject eye of bad fixation by changing the tolerance of misalignment for conducting automatic measurement corresponding to time after starting alignment. SOLUTION: The light flux of a light source 32 for measurement is incident on prisms 25a and 25b through which the light of its wavelength only is transmitted. At a correct actuation distance, a spot image of the light source 32 for measurement is formed as two luminescent spots disposed in parallel along a vertical line close to a center on an image pickup element 27. As the luminescent spots of alignment are reflected on the cornea of the subject eye E, key input to start auto-alignment is conducted, and drive motors 4, 10, and 15 are driven to set it to a correct alignment position. When the fixation of the subject eye E is bad, and it is hard to be set to the correct alignment position, the range of the correct alignment position is enlarged corresponding to time after starting, thereby automatic measurement by auto-alignment can be conducted even to the subject eye of bad fixation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus such as a non-contact tonometer for automatically aligning an eye to be inspected with a measuring head and automatically measuring when an alignment deviation is within a predetermined range. It is about.

[0002]

2. Description of the Related Art Conventionally, there has been known a non-contact tonometer which automatically adjusts the alignment between an eye to be inspected and a measuring head and automatically performs measurement when an alignment deviation falls within a predetermined range.

[0003]

However, in the above-mentioned conventional example, when fixation of the eye to be inspected is poor, it takes time for alignment alignment, and it may be difficult to start the measurement. However, there is a problem that is increased. In addition, when the measurement start switch is pressed and the measurement is forcibly performed when the misalignment is out of the predetermined range, the measurement is performed regardless of the magnitude of the misalignment. There is a problem that useless measurement is performed.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an ophthalmologic apparatus that can quickly measure an eye to be examined with poor fixation.

Another object of the present invention is to provide an ophthalmic apparatus capable of preventing useless measurement with low reliability.

[0006]

An ophthalmologic apparatus according to the present invention for achieving the above object has an alignment detecting means for detecting an amount of misalignment between an eye to be inspected and a measuring head, and the measurement based on the amount of misalignment. Driving means for moving the position of the head, control means for automatically performing alignment with the subject's eye and performing measurement when the amount of alignment deviation is within an allowable range, and time for starting the movement of the measuring head. Changing means for changing the allowable range accordingly.

An ophthalmologic apparatus according to the present invention comprises: an alignment detecting means for detecting an amount of misalignment between an eye to be inspected and a measuring head; a driving means for moving the position of the measuring head based on the amount of misalignment; Control means for performing a measurement when the amount of alignment deviation detected by the alignment detecting means is within a first allowable range by performing a positional alignment with the subject's eye, inputting means for starting measurement, and performing automatic positioning. Prohibiting means for prohibiting measurement if the amount of misalignment exceeds a second allowable range wider than the first allowable range when forcibly performing measurement by the input of the input means during the operation. It is characterized by having.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a cross-sectional view of an auto-alignment tonometer according to an embodiment. A guide shaft 2 and a feed screw 3 are horizontally mounted on a left-right movement frame 1. Has been fixed. A vertically moving frame 5 is mounted on the left and right moving frame 1, and a bearing 6 and a female screw bearing 7 fixed to a lower portion of the vertically moving frame 5 respectively include a guide shaft 2 and a feed screw 3 of the left and right moving frame 1. The vertical movement frame 5 can be moved in the horizontal direction.

A guide shaft 8 and a feed screw 9 are provided upright on the vertically movable frame 5, and a vertically driven motor 10 is fixed below the vertically movable frame 5. Is directly connected to one end. The guide shaft 8 and the feed screw 9 are respectively fitted to a bearing (not shown) fixed to the longitudinal frame 11 and a female screw bearing 12 so that the longitudinal frame 11 can be moved up and down. A guide shaft 13 and a feed screw 14 are installed on the front-rear movement frame 11, and a front-rear drive motor 15 is directly connected to one end of the feed screw 14, and the front-rear drive motor 15 is fixed to the front-rear movement frame 11. .

A guide shaft 13 and a feed screw 14 of the longitudinal movement frame 11 are fitted in a bearing (not shown) and a female screw bearing, respectively, fixed to the tonometry part 16. 14 rotates, and the tonometry unit 16 can move in the front-back direction along the guide shaft 13. In this manner, a mechanism is configured to move the tonometry unit 16 three-dimensionally freely in the front-back, up-down, and left-right directions with respect to the eye E to be examined.

A joint 17 of an air inlet (not shown) is attached to a side surface of the tonometry unit 16.
An air generator for blowing air is connected to 7 via a flexible tube. The air generator is composed of a rotary solenoid, a piston, an arm for moving the piston, and a cylinder. The piston is moved horizontally by the rotation of the rotary solenoid, and the air in the cylinder is passed through the flexible tube and the joint 17 to measure the intraocular pressure. To be sent to.

Inside the intraocular pressure measuring unit 16, a nozzle 20 is disposed on an optical path O1 facing the eye E, and two lenses 21 and 22 are provided before and after the outside of the nozzle 20, and a dichroic mirror 23 is provided behind the two lenses 21 and 22. As shown in FIG. 2, a mask 24, prisms 25a and 25b, a lens 26, and an image sensor 27 are sequentially arranged. A lens 2 is provided on the optical path O2 in the incident direction of the dichroic mirror 23.
8, a half mirror 29, a dichroic mirror 30, a projection lens 31, and a measurement light source 32 are arranged. An aperture 33 and a light receiving element 34, which is a light receiving unit of a corneal deformation detection system, are arranged in the reflection direction of the half mirror 29. A fixation LED light source 35 is arranged in the direction of incidence 30.

FIG. 3 shows a block diagram of the electric control unit. An MPU 40 for controlling the system is provided. The output of the image sensor 27 is connected to the MPU 40 and the image memory 42 via an A / D converter 41. , The image memory 42 is the MPU 4
Connected to 0. The output of the light sensor 34 and the pressure sensor 43 that detects the pressure in the air chamber of the tonometry unit 16 is A
It is connected to the MPU 40 via the / D converter 44.
The output of the MPU 40 is connected to the left / right drive motor 4, the up / down drive motor 10, and the front / rear drive motor 15 via the motor drive circuit 45 to control the rotation direction and drive speed of each of the motors 4, 10, and 15. Is connected to the measurement light source 32 and the fixation LED light source 35 via the driving circuit 46, and has a function of controlling the on / off of each of the light sources 32 and 35 and the amount of light, and is further connected to a rotary solenoid 47. And has a function of controlling the drive.

First, the subject sits in front of the tonometry unit 16 and looks at the fixation LED light source 35 through the fixation target projection optical system. The light flux from the fixation LED light source 35 is reflected by the dichroic mirror 30, passes through the half mirror 29, passes through the lens 20 through the lens 28, and is guided to the eye E to be inspected.

In the observation optical system, the observation image of the eye E to be examined passes through the lenses 21 and 22 outside the nozzle 20, passes through the dichroic mirror 23, passes through the central opening of the mask 24, and passes through the lens 26. The light is then guided to the image sensor 27 and displayed on a display (not shown). The examiner operates a trackball or the like while watching the image on the display, and operates the imaging device 27 of the observation optical system of the tonometry unit 16.
Then, the front-rear, up-down, left-right drive motors 4, 10, 15 are driven to perform rough alignment so that the subject's eye E is imaged.

In the alignment projection optical system, the light beam from the measurement light source 32 passes through the projection lens 31, the dichroic mirror 30, and the half mirror 29, and
8. Irradiated into the nozzle 20 via the dichroic mirror 23, and directed toward the eye E to be inspected.

In the alignment light receiving optical system, a part of the optical system is shared with the observation optical system, and the light beam reflected by the cornea of the eye E passes through the lenses 21 and 22 and passes through the dichroic mirror 23. Partially transmitted, mask 2
4, the light enters the prisms 25a and 25b that transmit only the light of the wavelength of the measurement light source 32 and is separated into two light beams. One light beam is refracted downward by the left prism 25a,
The other light beam is refracted upward by the right prism 25b.

Thus, at the proper working distance, the spot image of the measuring light source 32 is formed as two bright spots on the vertical line near the center on the image sensor 27. When the working distance shifts back and forth, each of the two luminescent spots relatively moves in different left and right directions based on the luminescent spot position at the proper working distance. When the intraocular pressure measurement unit 16 moves in the up, down, left, and right directions with respect to the eye E, both the two bright points move in the up, down, left, and right directions without changing their relative positions according to the amount of shift.

The output of the image pickup device 27 which is a light receiving section of the observation optical system and the alignment optical system is sent to a display (not shown) via an image synthesizing circuit. The image synthesizing circuit receives a character synthesizing signal from the MPU 40 in order to display an intraocular pressure measurement result and an alignment index, and synthesizes it with an observation image and displays the synthesized image on a display. In addition, the observation image subjected to the alignment detection processing is a digital image A
The data is sent to the image memory 42 via the / D converter 41. The image stored in the image memory 42 is taken into the MPU 40, and the alignment position is detected.

When a key input for starting auto-alignment is performed in a state where the alignment bright spot is reflected on the cornea of the eye E, the position of the alignment bright spot is detected, and the control signal of the MPU 40 is output in accordance with the amount of the shift. Motor drive circuit 45
To the front, back, up, down, left and right drive motors 4, 10, 15
Is driven. In this way, the feedback control of the auto alignment using the alignment optical system is performed, and the intraocular pressure measurement unit 16 is moved and set to an appropriate position so as to accurately match an appropriate alignment position with respect to the eye E to be inspected. The driving of these motors 4, 10, 15 is as follows.
When the eye E cannot be detected by the observation optical system or the alignment optical system, the eye E can be driven by a trackball, a mouse, or a key input operation.

In this way, when the amount of misalignment reaches a proper alignment state within a predetermined range,
A trigger signal is generated from the MPU 40 to the drive circuit 46,
The rotary solenoid 47 is automatically driven. As a result, air is sent from the air generator to the air chamber, and air is blown from the nozzle 20 to the cornea.

The projection optical system of the corneal deformation detection system is used in common with the alignment projection optical system, and the light beam emitted from the measurement light source 32 is projected by a projection lens 31, a dichroic mirror 30,
The light passes through the half mirror 29, is irradiated into the nozzle 20 through the lens 28, and travels toward the eye E to be inspected. The cornea is deformed by the blown air, and the cornea reflected light beam passes through the lenses 21 and 22, is partially reflected by the dichroic mirror 23, is partially reflected by the half mirror 29, and is received by passing through the aperture 33. It is led to the element 34. The output of the light receiving element 34 in this predetermined deformed state becomes a pulse, and the pressure in the air chamber at the peak is measured by the pressure sensor 43. The signal photoelectrically converted by the pressure sensor 43 and the light receiving element 34 is A / A It is digitized by the D converter 44 and the MPU
It is sent to 40 and converted to intraocular pressure.

At this time, if the fixation of the eye E to be examined is poor and the eye E does not match the proper alignment position, the range of the proper alignment position is increased as shown in FIG. 4 according to the time from the start of the automatic alignment. In addition, the automatic measurement by the automatic alignment can be performed on the eye E having poor fixation.

For a subject E whose fixation is very poor and automatic measurement cannot be performed by auto-alignment even if the range of the proper alignment position is widened, a measurement start switch is normally pressed to start auto-alignment. The measurement is forcibly interrupted, but if the alignment deviation at this time is too large, a measurement error will occur even if the measurement is performed, resulting in unnecessary measurement. For this purpose, it is determined whether or not the alignment position when the measurement start switch is pressed is within a predetermined range for performing the forced measurement, and if not, the measurement is not performed. .

In accordance with the time from the start of the automatic alignment, the range of the appropriate alignment position is kept constant without being widened, and the measurement start switch is pressed for the eye E having poor fixation to interrupt the automatic alignment. When the measurement is forcibly performed, it is determined whether the alignment position when the measurement start switch is pressed is within a predetermined range for performing the forced measurement. May not be measured.

The present invention can be used not only for the tonometer but also for other ophthalmic instruments such as a fundus camera and an eye refractometer.

[0027]

As described above, the ophthalmologic apparatus according to the present invention changes the allowable range of the misalignment according to the time from the start of the movement of the measuring head, so that the eye to be examined with poor fixation can be prevented. Can also make quick measurements,
The burden on the subject can be reduced.

In the ophthalmologic apparatus according to the present invention, since the fixation of the subject's eye is poor during auto alignment and the misalignment does not fall within a predetermined range, when the measurement start switch is pressed and the measurement is forcibly performed. When the misalignment is larger than the predetermined value, the measurement is prohibited, so that useless measurement such as a measurement error can be prevented, and the burden on the subject can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an intraocular pressure measurement unit according to an embodiment.

FIG. 2 is a front view of a mask and a prism.

FIG. 3 is a configuration diagram of a block circuit of an electric control unit.

FIG. 4 is a graph showing an allowable range of an alignment deviation.

[Explanation of symbols]

 1, 5, 11 Movable frame 4, 10, 15 Motor 16 Intraocular pressure measurement unit 20 Nozzle 24 Mask 25a, 25b Prism 27 Imaging device 32 Light source for measurement 34 Light receiving device 35 Fixation light 40 MPU 42 Image memory 43 Pressure sensor 47 Solenoid

Claims (2)

[Claims] 1. An alignment detecting means for detecting an amount of misalignment between an eye to be inspected and a measuring head; a driving means for moving the position of the measuring head based on the amount of misalignment; And control means for performing measurement when the amount of alignment deviation is within an allowable range, and changing means for changing the allowable range according to the time from the start of movement of the measuring head. machine. 2. An alignment detecting means for detecting an amount of misalignment between the eye to be inspected and the measuring head; a driving means for moving the position of the measuring head based on the amount of misalignment; Control means for performing measurement when the amount of alignment deviation detected by the alignment detection means is within a first allowable range; input means for starting measurement; and input means for performing automatic alignment. And a prohibiting means for prohibiting the measurement when the alignment deviation amount exceeds a second allowable range which is wider than the first allowable range when the measurement is forcibly performed by inputting the information. machine.