JPH03267039A - Eye refractometer - Google Patents

Abstract

PURPOSE:To obtain results of measurement with a higher reliability by providing a display means to display an optical distance of a fixed target in an eye refrac tometer which measures a far point refraction capacity exceeding at least two latitudes in a eye to be inspected. CONSTITUTION:This is provided with presentation optical systems 1, 2 and 4 to present a fixed target 3 with a variable optical distance to an eye E to be inspected and measuring optical systems 16-24 to measure eye refraction capacity of the eye to be inspected and a far point refraction capacity exceeding at least two latitudes is measured. Here, a TV monitor 27 displays the optical distance of the fixed target 3. This enables the checking to determine whether the eye to be inspected is led to a misty condition normally or not, namely, whether a measured value is reliable or not, thereby achieving a correct measure ment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to an eye refractometer used, for example, in eyeglass stores and eye clinics.

[Prior Art] Conventionally, this type of device has a built-in fixation target for fixating the subject's eye, but when the subject's eye looks into the fixation target inside the instrument housing, This results in so-called mechanical myopia, so in order to eliminate this, a fog method is used in which the optical distance of the fixation target is moved to bring the subject's eye into a desired accommodative state.

FIG. 5 shows the configuration of the optical target presenting optical system of such a conventional device, in which projection lenses l, 2, fixation target 3,
A projection light source 4 is arranged on the optical axis. The fixation target 3 and the projection light source 4 are configured to move together in the optical axis direction by, for example, a cam barrel 5, and the amount of rotation of the cam barrel 5 is controlled by a stepping motor 7 or the like via a gear 6. The position in the optical axis direction can be controlled by Further, at this time, the drive circuit 8 of the stepping motor 7 is given a drive output from the arithmetic control circuit 9 of the device, and a zero detection mechanism 10 is provided for detecting the reference rotational position of the cam cylinder 5. It is being

In such a conventional device, the projection light source 4 emits the fixation target 3.
The light flux that has passed is projected onto the eye E by the projection lens 2. At this time, the eye E to be examined is adjusted so that the image of the fixation target 3 can be seen clearly. The same visual target 3 and the projection light source 4 are connected through the tube 5.
When , the accommodation position of the eye E to be examined changes. In this way, the device moves the fixation target 3 little by little and automatically repeats the operation of measuring each parameter of the eye refractive power with the eye refractive power measuring section (not shown), and calculates the fluctuations in the measured values each time. When the optometry E determines that the desired fog state has been reached, the measured value at this time is taken as the final measured value. Such a conventional device is based on the premise that adjustment is performed so that the eye E to be examined can reliably follow the movement of the fixation target 3 and see the fixation target 3 clearly.

[Problem to be solved by the invention] However, even if the device makes a wrong judgment when the accommodation of the subject's eye E is poor or the accommodation speed is slow, or when the subject is not concentrating on the measurement, (The reliability of the measurement results is not very high.)

An object of the present invention is to provide an eye refractometer that solves the above-mentioned problems and provides highly reliable measurement results.

[Means for Solving the Problems] In order to achieve the above object, the ocular refractometer according to the present invention includes a presentation optical system that presents a fixation target with a variable optical distance to the eye to be examined; an eye refractometer that measures the far point refractive power of at least two meridians or more of the eye to be examined; It is characterized by this.

[Function] The ocular refractometer having the above-mentioned configuration detects the position of the isotropy target under measurement and displays its optical distance using the display means.

[Example] The present invention will be explained in detail based on the example illustrated in FIGS. 1 to 4. Note that the same reference numerals as in FIG. 5 represent the same members.

FIG. 1 is a configuration diagram, in which an optical path splitting mirror 11 is installed obliquely from the eye E side, a guichroic mirror 12 which is also installed obliquely and transmits visible light and reflects infrared light, and anterior segment imaging. A lens 13, a half mirror 14, and an image sensor 15 are arranged on the optical axis path O1. On the optical path 02 bent by the guichroic mirror 12, a lens 16, a mirror 17,
A perforated mirror 18, a projection chart 19, a condenser lens 20, and a measuring infrared light source 21 are arranged. Also,
On the optical path 03 between the perforated mirror 18 and the half mirror 14, a light receiving aperture 22 having a plurality of apertures, a lens 23,
A wedge prism plate 24 is provided. On the other hand, on the optical path 04 bent by the optical path splitting mirror 11, a projection lens 1.2, a fixation target 3, and a projection light source 4 are provided, similar to the conventional example described above. Further, the cam cylinder 5, gear 6, stepping motor 7, drive circuit 8, arithmetic control circuit 9, and zero detection mechanism 10, which are the drive mechanism for cooperating the visual target 3 and the projection light source 4, are also the same as in the conventional example described above. It is provided.

The output signal of the image sensor 15 is input to the arithmetic control circuit 9,
The arithmetic control circuit 9 is equipped with an algorithm for calculating each parameter of the eye refractive power from this signal, and also has a function of outputting a signal, and this control signal is given to the drive circuit 8 as a drive input. Further, the output of the zero detection mechanism 10 is connected to an arithmetic control circuit 9, and the arithmetic control circuit 9 detects the fixation target 3.
The adjusted position is output as, for example, a diopter amount from the reference position. This position output and the aforementioned calculation results are sent to a text display memory 25 which has the function of generating a video signal and displaying characters on the television screen, and the video output of this text display memory 25 is
The output signal of the image sensor 15 is combined with the combining circuit 26 and displayed manually on a television monitor 27 .

Therefore, the fixation target 3 illuminated by the projection light source 4 is presented to the eye E through the optical path splitting mirror 11 by the action of the projection lens 1.2. Here, a visible image of the anterior segment illuminated by external light is formed on the imaging element 15 by the action of the imaging lens 13. The fundus of the emmetropic eye of the eye E to be examined and the image sensor 15 are arranged in positions that are conjugate to each other with respect to the infrared light reflected by the gyroic mirror 12, and the infrared light emitted from the measurement infrared light source 21 is , a condenser lens 20, a projection chart 19, and a perforated mirror 1.
8, passes through the mirror 17 and the lens 16, and is further reflected by the dichroic mirror 2 to form the eye E.
If the eye E to be examined is an emmetropic eye, the measurement infrared light source 21
is formed on the fundus of the eye E to be examined. Further, the light beam reflected from the fundus travels backward along the same path, is reflected at the periphery of the perforated mirror 18, and is divided into a plurality of light beams by the light-receiving aperture 22. These light beams pass through the lens 23 and the wedge prism plate 2.
4 in different directions and reflected by the half mirror 14 to form a plurality of point images on the image sensor 15.

When performing measurements, as described above, first the fixation target 3 illuminated by the projection light source 4 is presented to the eye E to be examined, and the alignment between the device and the eye E to be examined is displayed on the television monitor 27. Adjust while looking at the anterior segment image. Next, when the measurement infrared light source 21 emits light, the pattern of the projection chart 19 is projected on the eye E to be examined, and the reflected light flux of infrared light from the fundus of the eye E to be examined forms a plurality of point images on the image sensor 15. From these relative positions, the calculation control circuit 9 calculates each parameter of the eye refractive power. In this way, the first measurement is performed at the position of the D diopter, for example, where the fixation target 3 is initially set, and the first refractive power is obtained. Therefore, the arithmetic control circuit 9
gives a control output to the drive circuit 8 to move the fixation target 3 to a position corresponding to the obtained refractive power, and when the fixation target 3 is moved, the next measurement is started and the next refractive power is obtained. .

Here, the fixation target 3 is further moved in a slightly distant direction and the measurement is performed again.The fogging method is repeated, and the measurement is continued while removing the adjustment force of the eye E, and the arithmetic control circuit 9 When it is determined that the adjustment has been removed from the amount of change in the value, the value at this time is given to the text display memory 25 as the final measurement result, and each parameter of the measurement result is displayed on the TV monitor 27 as shown in FIG. The position of the fixation target 3 at this time, given by the amount of diopters, etc., is the eye to be examined E.
The image is combined with the anterior segment image of the image and displayed. Based on the position of this fixation target 3, the examiner can confirm whether or not the eye E to be examined has been correctly guided to the cloudy state, that is, whether or not the final measurement result value is reliable, and in some cases, the examiner may repeat the It is possible to obtain highly reliable measured values by, for example, performing measurements. In this embodiment, each parameter of the measured value and the diopter amount indicating the position of the fixation target 3 may of course be displayed each time the measurement is performed in the process of removing the adjustment of the eye E. It is.

Furthermore, instead of displaying the position of the fixation target 3 by combining it by the combining circuit 26 and displaying it on the television monitor 27, as shown in FIG. It is also possible to provide a numerical display means 29 shown in FIG. Alternatively, it is of course possible to output by printing using a printer device that prints on recording paper or the like. Furthermore, the present invention can be similarly applied to a case where the apparent optical distance between the eye E and the fixation target 3 is changed by moving the projection lens 1.2 instead of moving the fixation target 3.

[Effects of the Invention] As explained above, in the ocular refractometer according to the present invention, the optical distance of the fixation target is displayed, so it is possible to determine whether or not the subject's eye has been correctly guided into the foggy state, that is, the measured values are reliable. It is possible to confirm whether the measurement is sufficient or not, and to perform accurate measurements.

[Brief explanation of drawings]

Drawings 1 to 4 show an embodiment of the ocular refractometer according to the present invention, in which Fig. 1 is a configuration diagram, Fig. 2 is an explanatory diagram of a television monitor, and Fig. 3 is a perspective view of the housing. FIG. 4 is a front view of the numerical display means, and FIG. 5 is a configuration diagram of a conventional fixation target optical system. 1.2 is a projection lens, 3 is a fixation target, 4 is a projection light source,
5 is a cam cylinder, 6 is a gear, 7 is a stepping motor, 8 is a drive circuit, 9 is an arithmetic control circuit, 10 is a zero detection mechanism, 11
is an optical path splitting mirror, 12 is a dichroic mirror 14
is a half mirror, 15 is an image sensor, and 18 is a perforated mirror.
19 is a projection chart, 21 is an infrared beam for measurement, 22 is a light receiving aperture, 24 is a wedge prism plate, 25 is a text display memory, 6 is a synthesis circuit, 7 is a TV monitor, 8 is a housing, 29 is a numerical value It is a display means.

Claims (1)

[Claims] 1. Equipped with a presentation optical system that presents a fixation target with a variable optical distance to the eye to be examined, and a measurement optical system that measures the eye refractive power of the eye to be examined, the far point refractive power of at least the second meridian of the eye to be examined. What is claimed is: 1. An eye refractometer for measuring the distance from the fixation target, characterized in that the eye refractometer is provided with a display means for displaying the optical distance of the fixation target.