JPH01178237A - Ophthalmic measuring apparatus - Google Patents

Abstract

PURPOSE:To measure the uneven state of the eyeground in real time by using a focus matching lens changing the focus matching state of an eyeground image to obtain the eyeground images of the first and second ranges of the eyeground and calculating the distance between the first and second ranges in the optical axis direction from the positions of respective focus matching lenses. CONSTITUTION:The first arbitrary range A1 on the eyeground of an eye 4 to be examined is set by regulating a setting volume and illuminated by an illumination light source 3 controlled by an illumination light source control circuit 2. The reflected light from the range A1 is incident to a photoelectric converter element 9 and a high frequency component is extracted by a high frequency component extraction circuit 11. Continuously the magnitude of the high frequency component is judged and a motor 14 is driven until the high frequency component becomes max. to move a focus matching lens 5 and the position A of the focus matching lens 5 at that time is calculated by a position operating circuit 13. Succeedingly, the second range A2 different from the first range A1 is set to calculate the position of the focus matching lens 5 where the focus matching image of the second range is obtained. Said position is set to B and the difference between the positions A, B is calculated by a position operation circuit 13 and the distance L between the first and second ranges in the optical axis direction is calculated to be displayed on a display device 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an ophthalmological measuring device, more specifically, an ophthalmological measurement device, which illuminates the fundus of an eye to be examined and measures the light reflected therefrom to obtain fundus information such as the uneven state of the fundus. Regarding an ophthalmological measuring device.

[Prior Art] Conventionally, in order to measure fundus information such as the uneven state of the fundus of the eye to be examined, methods have been used in which the uneven state is measured by projecting fundus moiré fringes, etc. and recognizing its shape, or by taking a stereoscopic photograph of the fundus. A known method is to take a photo and measure the unevenness from the stereoscopic photo.

[Problems to be Solved by the Invention] In the method of projecting fundus moiré fringes, etc. and performing shape recognition, or in the method of taking a stereoscopic photograph and measuring the irregularity of the fundus from the photograph, it takes time to recognize the shape and analyze the photograph. The disadvantage is that measurement results cannot be obtained in real time.
Another drawback is that the device becomes large.

[Means for Solving the Problems] In order to solve the problems described above, the present invention uses a focusing lens that is movably arranged along the optical axis and changes the focusing state of the fundus image, The first and second areas of the fundus
A configuration was adopted in which a focused fundus image of the range was obtained, and the distance in the optical axis direction of the first and second ranges of the fundus was determined from the position of each focusing lens.

[Function] In such a configuration, the first range of the fundus is defined,
The focusing lens is moved so as to obtain a focused image of the fundus image in the first range, the position of the focusing lens at that time is determined, and then a second range different from the first range is determined. The focusing lens is automatically operated at f3 so that a focused fundus image can be obtained at that position, and by determining the position of the focusing lens at that time, the first and second ranges of the fundus are determined. Since the distance in the optical axis direction can be determined, the uneven state of the fundus can be determined accurately, and fundus information can be obtained in real time. As a method for determining the first range and the second range of the fundus, there is a method of providing a means for setting a range for illuminating the fundus and thereby illuminating the first and second ranges, or a method of determining the first range and the second range of the fundus. A method is used in which a means for extracting a predetermined range from the image signal is provided, and fundus image signals in the first and second ranges are extracted and determined.

[Example] Hereinafter, the present invention will be described in detail according to an example shown in the drawings.

FIG. 1 shows a schematic configuration of an ophthalmological measuring device according to the present invention. In the figure, the reference numeral 1 indicates an illumination range setting circuit, which is connected to the illumination light source control circuit 2 and illuminates the fundus 4 of the examinee's eye 4 by the illumination light source 3.
Set the range (position) of a.

The specific circuit of the illumination range setting circuit 1 is illustrated in detail in FIG. 2, and the horizontal output signal generator (FIG. 2 (A))
and a vertical output signal generator (FIG. 2(B)). The horizontal output signal generator includes a horizontal range setting volume ■1, a horizontal position setting volume v2,
It is composed of a horizontal operational amplifier Q1, a resistor R1, and a resistor R2, and generates a horizontal output HO by inputting a horizontal sawtooth wave H generated by a horizontal sawtooth wave generation circuit (not shown), and also generates a vertical output signal. The circuit consists of a vertical range setting volume V3 and a vertical position setting volume V.
4. It is composed of a vertical operational amplifier Q2, resistors R3 and R4, and generates a vertical output Vo by inputting a vertical sawtooth wave V generated by a vertical sawtooth wave generation circuit (not shown).

The illumination light source 3 is composed of, for example, a flying spot scanner, and is adjusted so that the light is emitted at a position proportional to the horizontal output HO1 and the vertical output Vo of each of the horizontal operational amplifier Ql and the vertical operational amplifier Q2. By adjusting the range setting volume 1 and the vertical range setting volume 3, the size of the horizontal sawtooth wave and vertical sawtooth wave can be varied, and the size of the illumination range can be changed. can. Light from the illumination light source 3 passes through a focusing lens 5, a perforated mirror 6, and an objective lens 7, and is guided to the fundus 4a of the eye 4 to be examined.

The reflected light from the fundus 4a passes through the objective lens 7, is reflected by the reflective surface of the perforated mirror 6, passes through the condenser lens 8, and passes through the photoelectric conversion element 9, which is composed of, for example, a high electron multiplier tube.
is incident on the The output of the photoelectric conversion element 9 is sent to the video processing circuit 1
0, the reflected light from the fundus of the eye is converted into an electrical signal and becomes a video signal. After that, the video signal is transferred to the monitoring monitor 1.
6 and is input to the high frequency component extraction circuit 11. The high frequency component extraction circuit 11 extracts only the high frequency components of the video signal by passing it through a bypass filter. The extraction circuit 11 is connected to a high frequency component magnitude determination circuit 12,
The focusing lens moving motor 1 is controlled via the motor control and position calculation circuit 13 so that the extracted high frequency component is maximized.
4 to move the focusing lens 5. At this time, the position of the focusing lens can be calculated by the position calculation circuit 13, and the result can be displayed on the display 15.

Next, the operation of the device configured as described above will be explained.

First, adjust the horizontal range setting volume 1, the horizontal position setting volume v2, the vertical range setting volume 3, and the vertical position setting volume 4 as shown in Figures 4 and 5. Any first on the fundus as
Set range A1. This state is illustrated in step S1 of the flowchart of FIG. Subsequently, as illustrated in step S2, the illumination light source control circuit 2 illuminates the first range A1 of the eye 4 through the illumination light source 3 (step S3).

Subsequently, as illustrated in steps S4 to S36, the reflected light from the first range A1 is input to the photoelectric conversion element 9, and after being subjected to image processing by the image processing circuit 10, it is displayed on the monitoring monitor 16.
and is manually input to the high frequency component extraction circuit 11. A selected arbitrary range on the fundus of the eye is monitored by the monitoring monitor 16, and a high frequency component is extracted by the high frequency component extraction circuit 11.

Subsequently, in step S7, the high frequency component magnitude determination circuit
The magnitude of the high frequency component is determined, and the motor 14 is driven to move the focusing lens 5 until the high frequency component becomes maximum (steps 58 to 510). When the high frequency component reaches the maximum, the position calculation circuit 1 calculates the position of the focusing lens 5 at that time.
3 (step 5ll), and display the result on display 1.
Displayed on 5. Let A be the position of the focusing lens at this time.

Next, a second range A different from the first range A1 described above
2 is set, and the position of the focusing lens 5 where a focused image in the second range can be obtained is determined as shown in steps S12 to S22. Let the position be B, and step S2
3, the difference between the position A of the first focusing lens and the position B of the second focusing lens is determined by the position calculation circuit 13, and the result is displayed in step S24, and the difference between the first and second ranges is calculated. The distance L in the optical axis direction (see FIG. 4) is determined and displayed on the display 15.

FIG. 6 shows another embodiment of the present invention, in which the illumination range of the fundus by the illumination light source is set as in the embodiment of FIG. Unlike the method of setting the second range, a configuration is used in which an arbitrary range of the high frequency component of the video signal is set to set the first range and the second range.

Components that are the same as or similar to those in FIG. 1 are given the same reference numerals, and their explanations will be omitted.

In the embodiment shown in FIG.
is located. The detailed configuration of this circuit 20 is shown in FIG. 7, and the counter circuit 21 manually counts the horizontal drive signal HD, vertical drive signal VD, and clock signal CLK obtained from a synchronization signal generation circuit (not shown). and set the desired range. The extraction circuit 22 extracts the high frequency component of the video signal a (see FIG. 8(A)).
, as shown in FIG. 8(B), the signals in only the designated range R are extracted, and the high frequency video signal C within that range is obtained as shown in FIG. 8(C). Further, the range setting signal from the range setting and sampling circuit 20 is connected to the monitoring monitor 16, and any selected range on the fundus of the eye is monitored.

In this embodiment as well, the size determination circuit 12 and motor control circuit move the position of the focusing lens 5 via the motor 14 so that the high frequency component of the extracted portion is maximized, and the position calculation circuit 13 The calculation is performed and the result is displayed on the display 15.

Further, a second range different from the first range is set, the position of the focusing lens 5 is determined by performing similar processing, and the distance between the first and second ranges is determined from the difference, and the distance between the first and second ranges is determined. display on top.

[Effects of the Invention] As explained above, in the present invention, a focusing lens is provided that is movably arranged along the optical axis and changes the focusing state of the fundus image, and the focusing lens is arranged to be movable along the optical axis and to change the focusing state of the fundus image. The system automatically obtains focused images of the fundus in different second ranges, and calculates the distances in the optical axis direction of the first and second ranges of the fundus from the positions of the respective focusing lenses, so it can be done in real time. The advantage is that measurement results can be obtained and that it can be realized with a relatively simple and compact device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the schematic structure of the device of the present invention, and Fig. 2 (
A) and (B) are detailed circuit diagrams of the illumination range setting circuit, 3rd
The figure is a flowchart explaining the operation, and Figures 4 and 5 are a cross-sectional view and a front view of the fundus to be measured, respectively.
6 is a block diagram for explaining another embodiment, FIG. 7 is a detailed circuit diagram of the range setting circuit, and FIGS. 8(A) to 8(C) are waveform diagrams of the circuit of FIG. 7. 1... Illumination range setting circuit 2... Light source control circuit for illumination 3... Light source for illumination 4... Eye to be examined 10...
-Video processing circuit 11...High frequency component extraction circuit 12...High frequency component magnitude determination circuit 13...Motor control and position calculation circuit 16...Monitoring monitor □-;, -t-' -12■ -1 12■ A1 Release 1 No Oka no Han General r1 Iris 3 Takumi rfJ Establishment Gakua Each 4 Narukuchi Diagram 7 Procedures Amendment Release) March 15, 1986

Claims (1)

[Scope of Claims] 1) An ophthalmological measurement device that illuminates the fundus of the examined eye and measures reflected light from the fundus to obtain fundus information, which is disposed movably along the optical axis and focuses the fundus image. A focusing lens that changes its state, and an automatic focus that receives reflected light from the fundus, determines the focusing state by extracting high frequency components of the fundus image, and moves the focusing lens to the focusing position. an adjusting means; obtaining focused images of the fundus of the first range and a second range different from the first range of the fundus; An ophthalmological measuring device characterized by measuring distance. 2) The ophthalmological measuring device according to claim 1, further comprising an illumination range setting means for setting a range for illuminating the fundus, and illuminating the first and second ranges. 3) providing a setting means for setting a predetermined range of the fundus image signal, and extracting the fundus image signals in the first and second ranges;
Claim 1 in which the in-focus state is determined
The ophthalmological measuring device described in Section. 4) The ophthalmological measurement device according to claim 1, 2, or 3, wherein a flying spot scanner is used as an illumination light source, and the fundus is illuminated by sequentially scanning the fundus image.