JPH04226621A - Ophthalmorefractometer - Google Patents

Abstract

PURPOSE:To shorten the time for measurement and to allow selfexamination by changing the diopter of a visual index to be exhibited to an eye to be examined so as to be suitable for the eye before the start of ophthalmorefractive value measurement. CONSTITUTION:The luminous flux from a light source 1 for ophthalmorefractive value measurement advances in an optical path and arrives at the eye E to be examined. The cornea reflected luminous flux P0 at the eye E to be examined advances in an optical path Oa or optical path Ob and is received by a photosensor 15a or photosensor 15b, and the alignment state of the eye E to be examined is successively monitored by the quantity of the received light. On the other hand, the eyeground reflected luminous flux is received in an optical position detector 10, by which the ophthalmorefractive value is measured and, therefore, the ophthalmorefractive value is measured when the eye E to be examined comes to the prescribed position. A lens 13 is moved in the optical axis direction in accordance therewith to change the diopter of the index 12 so as to be suitable for the eye E to be examined.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye refractometer used, for example, in eye clinics.

0002

[Prior Art] Conventional eye refractometers improve the reliability of measured values by presenting a fixation target to the subject's eye and performing measurements while fixating on the fixation target. When the measurement switch is pressed, a rough eye refraction value is first measured, and the initial diopter of the fixation target is reset according to the eye refraction value, and then the actual measurement is performed.

0003

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, the measurement time after pressing the measurement switch is long, which is inconvenient especially for subjects such as infants whose eyes move easily, and also for the first time. This method has the disadvantage that the fixation target may not be visible at the beginning of the measurement.

SUMMARY OF THE INVENTION An object of the present invention is to provide an eye refractometer which eliminates the above-mentioned drawbacks of the conventional example, reduces measurement time, and allows self-inspection.

[0005]

[Means for Solving the Problems] An ocular refractometer according to the present invention for achieving the above-mentioned object includes: means for detecting alignment state of an eye to be examined; optotype presenting means for presenting an optotype to the eye to be examined; An eye refractometer having a measurement optical system for measuring an eye refraction value for optometry, wherein the alignment state detection means continuously monitors the alignment state of the eye to be examined, and detects that the eye to be examined is within a predetermined range. In some cases, the apparatus is characterized by comprising a diopter changing means for changing the diopter of the optotype of the optotype presentation means based on the eye refraction value obtained by the measurement optical system.

[0006]

[Operation] The eye refractometer having the above configuration sequentially monitors the alignment state of the eye to be examined using the alignment state detection means, and when the eye to be examined is detected to be within a predetermined range, the obtained eye refraction is The diopter of the optotype presented to the eye to be examined is set based on the value, so that the optotype is within the visible range at the start of measurement, thereby shortening the measurement time.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail based on the illustrated embodiments. FIG. 1 shows a configuration diagram, in which an optical path O from a point-like light source 1 for measuring the eye refraction value conjugate to the fundus Er of an emmetropic eye to the eye E to be examined is shown.
1, a lens 2, a diaphragm 3 having an aperture 3a as shown in FIG. 2 and conjugate to the pupil Ep, a small mirror 4, a dichroic mirror 5, and an objective lens 6 are arranged. On the optical path O2 behind the small mirror 4, there is a diaphragm 7 having six apertures 7a to 7f as shown in FIG. 3, a lens 8, and six wedge prisms 9a to 9f as shown in FIG. A separating prism 9 and an optical position detector 10 such as a two-dimensional CCD conjugate to the emmetropic fundus are sequentially arranged. On the other hand, the optotype 1 is on the optical path O3 from the optotype illumination light source 11 to the eye E to be examined.
2. An optotype lens 13 is disposed that can be moved in a direction along the optical axis by a driving means to be described later. In addition, the eye to be examined E
On the optical path Oa and the optical path Ob tilted at the same angle,
A lens 14a, a lens 14b, a photosensor 15a, and a photosensor 15b are arranged. Furthermore, a control circuit 16 is provided to control the entire apparatus, and the control circuit 16 includes the eye refraction value measurement light source 1, the optical position detector 10,
The control circuit 16 is connected to a drive section 17 for driving the optotype lens 13, a power switch 18, and a display means 19 for displaying measurement results. Although not shown, the control circuit 16 is also connected to the photosensors 15a and 15a. It is connected.

The light beam from the light source 1 for measuring the eye refraction value is on the optical path O.
1, passes through the lens 2 and the aperture 3a of the diaphragm 3, is reflected by the small mirror 4, passes through the dichroic mirror 5 and the objective lens 6, and reaches the eye E. The fundus reflected light flux returns along the same optical path and passes through the small mirror. The optical position detector 1
0, six fundus reflection images Ma to Mf are formed as shown in FIG. 5, and the ocular refraction value is calculated from their positional relationship.

On the other hand, the corneal reflected light flux Po travels along the optical path Oa or the optical path Ob, and is imaged onto the photosensor 15a and photosensor 15b by the lenses 14a and 14b. When the eye E to be examined comes to a predetermined position, the photosensors 15a, 1
5b forms an image at the center of the corneal reflected light beam Po as shown in FIG. 6(a). In this case, the placement positions of the photosensors 15a and 15b are set so that the amount of light received increases, and the positional relationship between the two is such that the eye E to be examined deviates from a predetermined position in a plane perpendicular to the optical axis of the eye refractometer. In this case, the result will be as shown in Fig. 6(b). Furthermore, if the eye E to be examined deviates from the predetermined position in the direction of the optical axis of the eye refractometer, the position of the eye E will be aligned as shown in FIG. 6(c). Whether or not it is in a predetermined position is detected.

Further, the visible light flux from the optotype illumination light source 11 illuminates the optotype 12 from behind, passes through the optotype lens 13, is reflected by the dichroic mirror 5, passes through the objective lens 6, and reaches the eye E to be examined. By this, optotype 1 is placed on the eye E to be examined.
2 is presented.

Next, at the time of measurement, turn on the power switch 1 of the eye refractometer.
8, the control circuit 16 turns on the light source 1 for measuring the eye refraction value for a certain period of time. Photo sensor 15 during this time
The alignment state of the eye E to be examined is detected from the amount of light received by a and 15b, and as soon as the eye E comes to a predetermined position, the eye refraction value is measured from the light image received by the optical position detector 10. Based on the driving unit 17, the optotype lens 13 is
is moved, the diopter of the optotype 12 is changed, and diopter guidance is performed. This series of measurements and diopter changes are repeated several times per second. Therefore, in the case of an eye refractometer in which the examiner performs measurements, diopter guidance has been completed at the time the measurement switch is pressed, so highly reliable results can be obtained immediately with a single measurement. Furthermore, in the case of self-measurement, it is sufficient to conclude the measurement by determining that the diopter guidance is complete when the measured value displayed on the display means 19 becomes a substantially constant value and no longer fluctuates. Note that another light source may be provided for alignment, and in that case, the eye refraction value measurement light source 1 is turned off before the eye E comes to a predetermined position and measurement is started.

Furthermore, the fundus reflection image M on the optical position detector 10
The alignment state of the eye E to be examined is detected from the positions a to Mf, and the lenses 14a, 14b, photosensors 15b, 1
It is also possible to omit 5b. That is, for example, if the position of the eye E to be examined deviates from the optical axis, the pupil Ep and the aperture 7 of the aperture 7
When the positional relationship with a to 7f is as shown in FIG. 7, the total luminous flux does not pass through the pupil Ep, so the fundus reflection images Md to Mf are displayed on the optical position detector 10 as shown in FIG. only is imaged. In this way, detection of the six fundus reflection images Ma to Mf on the optical position detector 10 can be used to detect the alignment state, and the alignment detection means is not limited to the above-mentioned one.

FIG. 9 shows a main part configuration diagram of the second embodiment,
A microswitch 21 is attached to the forehead rest 20, and this microswitch 21 is connected to the control circuit 16, and the other configurations are the same as in the first embodiment. In this embodiment, the microswitch 21 is turned on when the subject contacts the forehead portion F with the forehead rest 20, and the cycle of measurement and diopter change of the above-described embodiment is executed.

[0014] Measurement is carried out at the moment when the power switch 18 is turned on.
Alternatively, the measurement cycle can be started in synchronization with the opening and closing of the dust cover of the optical system of the eye refractometer, etc. Furthermore, if the eye refraction value is finally measured and the eye refraction value is displayed, it can also be used for self-examination. Furthermore, the method of measuring the refraction value is not limited to the above-mentioned embodiments, and may be other methods.

[0015]

Effects of the Invention As explained above, the ocular refractometer according to the present invention continuously monitors the alignment state of the eye to be examined using the alignment detection means, and when it is detected that the eye to be examined is in a predetermined position, the alignment state of the eye to be examined is detected. The diopter of the optotype presented to the subject's eye is changed based on the eye refraction value, and the test eye can see the optotype before the actual eye refraction value measurement begins, so the measurement time is reduced. It can be shortened and is particularly suitable for subjects such as infants whose eyes are easily moved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram.

FIG. 2 is a front view of the diaphragm.

FIG. 3 is a front view of the diaphragm.

FIG. 4 is a front view of the separation prism.

FIG. 5 is an explanatory diagram of a fundus reflection image on an optical position detector.

FIG. 6 is an explanatory diagram of the positional relationship between a photosensor and a corneal reflection image.

FIG. 7 is an explanatory diagram of the positional relationship between the pupil and the aperture in a state where alignment is shifted.

FIG. 8 is an explanatory diagram of a fundus reflection image on an optical position detector.

FIG. 9 is a plan view of a forehead rest according to another embodiment.

[Explanation of symbols]

1. Light source for measuring eye refraction value 10 Optical position detector 11 Light source for target illumination 12 Visual targets 15a, 15b Photo sensor 16 Control circuit 17 Drive section 18 Power switch 19 Display means 20 Forehead guess 21 Micro switch

Claims (2)

[Claims] 1. An eye refractometer comprising: an alignment state detection means for an eye to be examined; an optotype presentation means for presenting an optotype to the eye to be examined; and a measurement optical system for measuring an ocular refraction value of the eye to be examined, The alignment state detection means continuously monitors the alignment state of the eye to be examined, and when the eye to be examined is detected to be within a predetermined range, the optotype is detected based on the eye refraction value obtained by the measurement optical system. An eye refractometer characterized by having a diopter changing means for changing the diopter of the optotype of the presentation means. 2. The eye refractometer according to claim 1, further comprising an eye refraction value display means for simultaneously measuring and displaying the eye refraction value.