JPH0586213B2 - - Google Patents

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. There are disadvantages in that it takes a lot of time and measurement results cannot be obtained in real time, and 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, Obtain focused fundus images of the first and second ranges of the fundus, and
A configuration is adopted in which the distance in the optical axis direction of the second range is determined.

[Operation] In such a configuration, the first range of the fundus is determined, the focusing lens is moved to obtain a focused image of the fundus in the first range, and the focusing lens is moved to obtain a focused image of the fundus in the first range. The position of the lens is determined, and then a second range that is different from the first range is determined, and the focusing lens is automatically moved so that a focused fundus image at that position is obtained. Since the distance in the optical axis direction between the first and second ranges of the fundus can be determined by determining the position of the lens used for the purpose, it is possible to accurately determine the irregularity of the fundus, and to obtain fundus information in real time. becomes possible. Fundus 1
As a method for determining the range and the second range, a method is provided in which a means for setting a range for illuminating the fundus of the eye is provided, thereby illuminating the first and second ranges;
Alternatively, a method is used in which a means for extracting a predetermined range from the obtained fundus image signal is provided, and the 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 same figure, the reference numeral 1 indicates an illumination range setting circuit, which is connected to the illumination light source control circuit 2 and sets the range (position) of the fundus 4a of the examinee's eye 4 illuminated by the illumination light source 3. Set.

The specific circuit of the illumination range setting circuit 1 is shown in detail in FIG. 2, and is composed of a horizontal output signal generator (FIG. 2A) and a vertical output signal generator (FIG. 2B). There is. The horizontal output signal generator includes a horizontal range setting volume V1, a horizontal position setting volume V2, and a horizontal operational amplifier Q.
1. Consists of a resistor R1 and a resistor R2, and generates a horizontal output H ₀ by inputting a horizontal sawtooth wave H formed 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, a vertical position setting volume V4, a vertical operational amplifier Q2, and a resistor R.
3 and R4, and generates a vertical output V ₀ by inputting a vertical sawtooth wave V generated by a vertical sawtooth wave generating circuit (not shown).

The illumination light source 3 is composed of, for example, a flying spot scanner, and has a horizontal operational amplifier Q.
1. Each horizontal output of vertical operational amplifier Q2
Since it is adjusted so that the position proportional to H ₀ and vertical output V ₀ lights up, by adjusting the horizontal range setting volume V1 and the vertical range setting volume V3, you can create a horizontal sawtooth wave, a vertical sawtooth wave. The size of the waves can be varied, and the size of the illuminated area can be changed. Light from the illumination light source 3 is guided to the fundus 4a of the eye 4 to be examined through the focusing lens 5, the perforated mirror 6, and the objective lens 7.

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 enters the photoelectric conversion element 9 formed of, for example, a photomultiplier tube. The output of the photoelectric conversion element 9 is input to a video processing circuit 10, where the reflected light from the fundus of the eye is converted into an electrical signal and becomes a video signal. Thereafter, the video signal is input to a monitoring monitor 16 and a 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 high pass filter. The extraction circuit 11 is a high frequency component magnitude determination circuit 12
The focusing lens moving motor 14 is driven via the motor control and position calculation circuit 13 to move the focusing lens 5 so that the extracted high frequency component is maximized. 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 V1, the horizontal position setting volume V2, the vertical range setting volume V3, and the vertical position setting volume V4 to obtain the fundus as shown in FIGS. 4 and 5. Set an arbitrary first range A1 above. This state is illustrated at step S1 in the flowchart of FIG. Subsequently, as shown 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).

Then, as illustrated in steps S4 to S6,
The reflected light from the first range A1 is incident on the photoelectric conversion element 9 and subjected to image processing in the image processing circuit 10, followed by the monitoring monitor 16 and the high frequency component extraction circuit 1.
1 is input. 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 determines the magnitude of the high-frequency component, and the motor 14 is driven to move the focusing lens 5 until the high-frequency component becomes maximum (steps S8 to S10). When the high frequency component reaches the maximum, the position of the focusing lens 5 at that time is determined by the position calculation circuit 13 (step S11), and the result is displayed on the display 15.
Let A be the position of the focusing lens at this time.

Next, a second range different from the first range A1 described above is set.
Set range A2 of
As shown in S22, the position of the focusing lens 5 where a focused image in the second range can be obtained is determined. The position is set as B, and in step S23, 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 used in the step S23.
In step S24, the distance L between the first and second ranges 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. 6, a range setting and sampling circuit 20 is arranged between the high frequency component extraction circuit 11 and the magnitude determination circuit 12. This circuit 20
The detailed configuration is shown in FIG. 7, and the horizontal drive signal HD, vertical drive signal VD, and clock signal CLK obtained from a synchronization signal generation circuit (not shown) are shown in FIG.
is input to the counter circuit 21 and counted to set an arbitrary range. Out of the high frequency component video signal a in the sampling circuit 22 (see FIG. 8A),
As shown in FIG. 8B, the signal b only in the specified range R is extracted, and the high-frequency video signal c within that range is obtained as shown in FIG. 8C.
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 focusing lens 5 is connected to the focusing lens 5 via the size determining circuit 12 and the motor 14 in the motor control circuit so that the high frequency component of the extracted portion is maximized.
The position is moved, the position is calculated by the position calculation circuit 13, and the result is displayed on the display 15.

In addition, a second range different from the first range is set, and the same process is performed to find the position of the focusing lens 5. From the difference, the distance between the first and second ranges is found, and the display 15.

[Effects of the Invention] As described 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. A focused fundus image of the second range is automatically obtained, and the distance in the optical axis direction of the first and second ranges of the fundus is calculated from the position of each focusing lens, so it can be measured in real time. The present invention has the advantage that it is possible to obtain results and can be realized using a relatively simple and compact device.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a schematic configuration of the device of the present invention;
Figures 2A and B are detailed circuit diagrams of the illumination range setting circuit, Figure 3 is a flowchart explaining the operation,
4 and 5 are a cross-sectional view and a front view of the fundus to be measured, respectively, FIG. 6 is a configuration diagram explaining another embodiment, FIG. 7 is a detailed circuit diagram of the range setting circuit, and FIG. Figures A to C are waveform diagrams of the circuit of Figure 7. DESCRIPTION OF SYMBOLS 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...Monitor for monitoring.

Claims (1)

[Scope of Claims] 1. An ophthalmological measurement device that illuminates the fundus of an eye to be examined and measures reflected light from the fundus to obtain fundus information, the device being arranged movably along an optical axis and configured to monitor the focused state of the fundus image. and an automatic focusing lens that receives reflected light from the fundus, determines the in-focus state by extracting high-frequency components of the fundus image, and moves the focusing lens to the in-focus position. means for obtaining focused fundus images of a first range and a second range different from the first range of the fundus, and determining distances in the optical axis direction of the first and second ranges of the fundus from the positions of respective focusing lenses. An ophthalmological measuring device characterized by measuring. 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. According to claim 1, there is provided a setting means for setting a predetermined range of the fundus image signal, and the fundus image signal in the first and second ranges is extracted and the in-focus state thereof is determined. The ophthalmological measuring device described. 4. The ophthalmological measuring 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.