JP2941832B2 - Eye refractometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention measures an eye refractometer, particularly, for example, an eye refractive power on a visual axis passing through a fovea in a strabismic eye and an eye refractive power in a squint state. In addition, the present invention relates to an apparatus capable of quantitatively measuring the degree of strabismus as well as the eye refractive power and performing a precise diagnosis based on information on the eye refractive power and the eye position.

[Prior art] Conventionally, eye positions regarding strabismus, oblique position, etc. have been measured subjectively, but recently an attempt using a pupil image and a corneal reflection image of a light source in photography has been announced (54th Japan Chubu Ophthalmology Association Program Lecture Abstract Collection, P64, December 2, 1988). As a method for detecting the direction of the line of sight, a method has been proposed in which a pupil image and a corneal reflection image of a light source are obtained from a relative relationship using a video signal (Japanese Patent Laid-Open No. 57-81324).

[Problem to be Solved by the Invention] However, in the above-mentioned conventional example, it was not possible to easily measure the combined eye function of the eye refractive power and the eye position.

An object of the present invention is to provide an eye refractometer that can easily measure an eye position without adding a specially large additional mechanism to the eye refractometer.

Means for Solving the Problems In order to achieve the above object, in the present invention, a television for projecting the anterior segment of the eye to be examined for alignment, a binocular visual target, and a piece that can be freely inserted into and removed from the optical path of the visual target. Eye shield means and an eye refractometer having an eye position measuring light source, wherein the eye position measuring light source is positioned relative to the center position of the subject's pupil reflected on a television monitor between monocular and binocular vision. It is characterized by comprising a means for detecting a change amount of a deviation of a corneal reflection image position, and a calculating means for measuring an eye position of a subject's eye from the change amount.

According to the present invention, the eye refractive power is measured on the visual axis passing through the fovea by measuring the eye refractive power while obstructing the other eye with respect to the oblique eye. The eye refractive power is measured in the oblique state by measuring the eye refractive power in the state in which the eye is oblique, and the center position of the pupil of the subject's eye reflected on the television monitor between monocular and binocular vision The amount of shift of the position of the corneal reflection image with respect to is detected to quantitatively measure the strabismus.

Then, in the case of the measurement of the oblique position, the change amount of the deviation of the corneal reflection image position when shifting from the state of binocular vision to the state of monocular vision obstructing the target optical path of the eye to be measured is detected.

Embodiment FIG. 1 shows an embodiment of the present invention. The target 5 viewed by both eyes is an eye refractive power measuring means 6 having a television camera for alignment.
A mark 50 as shown in FIG. 2 is provided on the optical axis branched by the light splitting member 3 from the measuring optical axis 15 of FIG. Another mark 51 is provided at a position separated from the mark 50 by a predetermined distance in a direction perpendicular to the optical axis. The light source 1 is a light source for eye position measurement, and projects a light beam to the eye E through the light dividing member 2. E _i is a virtual image of the light source 1 by the cornea E _c . An anterior segment image reflected on a television camera in the eye refractive power measuring means 6 is projected on a monitor 8. Eye refractive power at the measurement adjust the pupil E _p the alignment mark 9. That is, the measurement optical axis 15 passes through the center of the pupil.
The shielding plate 4 is a means for alternately shielding one eye as shown in FIG. The light dividing member 3 has a property of reflecting visible light and transmitting near-infrared light used for measurement, and has a width sufficient for both eyes to see the optotype 5. Reference numeral 7 denotes a signal processing unit required for eye refractive power measurement, squint measurement, and the like. The frame holding these means moves the device and the subject's eye E three-dimensionally on a slide like a general eye refractometer.

As a measurement procedure, assuming that the oblique eye is on the measurement optical axis 15, the other eye opposite to the eye to be measured is first blocked by the blocking plate 4.
The eye to be measured looks at the mark 50 on the optical axis. Corneal reflection image E _i of the light source 1 is gaze come to almost the center of the pupil through the fovea. The combined pupil E _P to the mark 9 for measuring the corneal reflection image E _i position. Here, the measurement of the eye refractive power is performed, and may be performed simultaneously with the measurement of the eye position or non-simultaneously. It is preferable to use a CCD for a television camera to obtain a corneal reflection image _Ei position from a video signal. Corneal reflected image E _i may if so as to determine coordinates of maximum in the video signal because the highest point luminance on a television monitor screen. Next, the evil plate 4 is removed from the optical path and viewed with both eyes. Since the eye to be examined is oblique, the line of sight is off. At that time rotation point of the eye adjust the pupil E _P to again mark 9 because the pupil also shifted because it is not the center of the pupil. Since the line of sight is inclined, the corneal reflection image of the light source 1 is shifted from the pupil center. When you are a pupil alignment measures the position of the corneal reflected images E _i. In this case as well, the measurement of the refractive power of the eye is performed. Here obtains the coordinate position of the corneal reflection image E _i, determining the degree and direction of perspective from the difference between the coordinate position of the previous image of corneal reflection E _i. Now there are individual differences This difference depends on the distance on the optical axis 15 of the E _p and E _i. Precisely, individual calibration is required. For calibration, a mark corresponding to a predetermined visual angle, that is, a mark 51 which is separated from the mark 50 on the optical axis of the optotype 5 by a predetermined distance in a direction perpendicular to the optical axis is obtained, and the amount of movement of the corneal reflection image is obtained. What is necessary is just to obtain a perspective angle. Note that the light source 1 may also be used for refraction measurement. To the pupil center may use the video signal as the seek position of the corneal reflection image E _i is a possible alternative. Electronically moving mark 10 is generated it is matched with the third view of a cornea reflection image E _i moved by pressing any key 11, 12, 13, 14 while watching the image on the monitor on, for example, a monitor 8 The position may be measured.

The case of the oblique view has been described above, but in the case of the oblique position, the problem means 4 'is used. This is to obstruct the target optical path of the eye E itself. The coordinate positions of the cornea reflection image E _i calculated by Saegihei the target optical path of the eye under measurement E itself to the next calculated coordinate positions of the cornea reflection image without Hey barrier initially as a measuring means, the corneal reflection image of the light Find the difference from E _i . This blocking means does not interfere with the television and the refraction measurement optical path.

[Effects of the Invention] As described above, according to the present invention, it is possible to measure an eye position such as a strabismus and the like in addition to the measurement of the eye refractive power, and to perform a more precise diagnosis. That is, if the eye refractive power is measured by aligning the center of the pupil with a television, the eye position can be measured. An eye refractive power measurement value in the direction inclined by the angle is obtained together with the angle with respect to the oblique eye, and more diagnostic information is obtained by comparison with that on the visual axis passing through the fovea.

[Brief description of the drawings]

 FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a binocular optotype and a mark, FIG. 3 is a diagram showing a mark moving key, and FIG. In the drawing, 1 is a light source, 2 and 3 are light splitting members, 4 is a shielding plate, 5 is a binocular optotype, 6 is an eye refractive power measuring means, 7 is a signal processing means, and 8 is a monitor.

Claims (1)

(57) [Claims] 1. A television for projecting an anterior segment of a subject's eye for alignment, a binocular visual target, a one-eye guard that can freely enter and exit the visual target optical path, and an eye refraction having an eye position measuring light source. A dynamometer, and means for detecting a change amount of a shift of a corneal reflection image position of the eye position measurement light source with respect to a center position of a pupil of the subject's eye reflected on a television monitor between monocular vision and binocular vision. An eye refractometer provided with a calculating means for measuring an eye position of a subject's eye from the amount of change.