JPH0412730A - Eye refractive power measuring instrument - Google Patents

Abstract

PURPOSE:To constitute this measuring instrument so that loss of the light quantity is suppressed to the minimum, and also, a necessary space is small, the cost is low, and a glare test can be executed by providing a glare test target presented to an eye to be examined, and also, providing a glare light illumination light source in the optical path of a measuring target projection optical system. CONSTITUTION:In the optical system of the instrument, a movable measuring target (spot opening) is provided on an optical path for reaching a measuring light source 1 from an eye 9 to be examined, and an opening for a glare light is provided on the upper and the lower parts of the spot opening. A measuring target plate 4 is arranged. Also, a glare lamp for emitting a visible light for a glare test is arranged integrally in the rear part corresponding to the opening on the measuring target plate 4. In such a state, the opening for the glare of the measuring target plate 4 and the glare lamp 5 in its rear can be arranged in the appropriate position of the optical path extending from the measuring light source 1 to an eyeground of the eye 9, For instance, they are arranged on the measuring target. In this case, since an optical member for decreasing the light quantity such as a beam splitter is not required, the loss of the light quantity can be suppressed to the minimum.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an eye refractive power measuring device.

[Prior Art] In recent years, glare tests have come to be performed using a well-known eye refractive power side and window device.

Initially, a contrast target was placed on the turret board where the target for subjective measurement was placed, and an illumination light source (hereinafter referred to as a glare lamp) that produced glare light in the glare test was placed behind the target for subjective measurement. A method of providing an aperture around the optotype was attempted. However, since the visual target for self-awareness is projected by illumination light, there is a problem in that the glare lamp obstructs the optical path of the illumination light.

Therefore, it is conceivable to arrange a beam splitter in the optical path of the optical system to provide an optical path for the glare light source.

[Problems to be Solved by the Invention] However, as described above, arranging an extra beam splitter not only requires a large space and is expensive, but also has the disadvantage of causing a large loss of light quantity.

The present invention was devised in view of the above-mentioned drawbacks, and a technical problem is to provide an eye refractive power measurement device that can minimize the loss of light amount, take up a small space, and perform a glare test at low cost. do.

[Means for Solving the Problems] The eye refractive power measuring device of the present invention projects a measurement optotype onto the fundus of the eye to be examined, detects the position of the optotype image, and obtains refractive power information of the eye to be examined. The eye refractive power measurement device has a glare test optotype to be presented to the eye to be examined, and also includes illumination for glare light in the optical path of a measurement target projection optical system that projects the measurement optotype onto the fundus of the eye to be examined. It is characterized by the provision of a light source to enable glare testing.

Further, the glare test optotype is characterized in that it is arranged on a turret board on which visual acuity test optotypes are arranged.

Further, the illumination light source for glare light or the aperture provided on the subject side of the illumination light source is moved to a position substantially conjugate with the fundus of the subject's eye.

Further, the illumination light source for glare light or the opening provided on the subject side of the illumination light source is provided on the measurement target plate.

[Operation] Therefore, the glare aperture and the glare lamp behind it can be placed at an appropriate position on the optical path from the measurement light source to the fundus of the eye to be examined without interfering with the measurement optical path. For example, on a measurement target. At this time, since there is no need for an optical member such as a beam splitter that reduces the amount of light, the loss of the amount of light can be minimized. Further, by moving the glare lamp or the glare aperture to a position conjugate with the fundus of the eye, loss of light amount can be minimized. Furthermore, in the case of a method in which the measurement target is moved in objective measurement, the eye to be examined can be effectively illuminated as glare light by simply stopping the target at that position after the objective measurement.

[Example 1] Figure 1 is an optical system layout diagram of an eye refractive power measuring device according to an example, in which 1 is a measurement light source having a wavelength in the infrared region, 2.3
4 is a condensing lens, and 4 is a movable measurement optotype to be placed at a position conjugate with the fundus of the eye 9 to be examined (as shown in FIG. 2).
This is a measurement target plate having a spot aperture (spot aperture), and glare light apertures are provided above and below the spot aperture.

Reference numeral 5 denotes a glare lamp for emitting visible light for the Dallaire test, and it is integrally arranged at the rear portion corresponding to the opening on the measurement target plate 4. An appropriate number of openings and lamps can be provided as required, and a large number of openings and lamps may be arranged in a ring. Further, in order to test glare light from a certain direction, the light may be switched to emit light. Reference numeral 6.7 denotes an objective lens, and the objective lens 6 is selected so as to serve as an optical system for enlarging the fundus image at the position of the measurement target plate 4. 8.10, the beam splitter 11 is a mirror; 12.13, a relay lens; 14, a band-shaped corneal reflection removal mask placed at a position conjugate with the cornea of the eye to be examined; 15, moving together with the measurement target plate 4; 16 is an imaging lens. Reference numeral J7 denotes a measurement light receiving element, which rotates around the optical axis in synchronization with the measurement light source 1 and the corneal reflection removal mask 14. Reference numeral 18 denotes a first relay lens that is movable on the optical axis, and the amount of movement thereof is proportional to the spherical refractive power of the eye to be examined. 19 and 20 are positive cylindrical lenses with equal focal lengths, and both lenses are rotatable about the optical axis by the same amount in the same direction or in opposite directions.

Note that, as is well known, in order to create a cylindrical component using two cylindrical lenses, it is necessary to take into account the spherical effect and perform correction. 2
1 is a second relay lens, 22 is a turret plate located at the focal position of the second relay lens 21, and a fixation target for objective measurement;
Visual acuity measurement optotypes and contrast optotypes are arranged in a switchable manner. Here, a striped optotype may be used as the contrast optotype. Further, since it is necessary to provide a large number of optotypes on the turret board 22, the optical elements are selected so that the sizes of the optotypes and the fundus image are equal to each other. 23 is a condensing lens, and 24 is an illumination lamp.

With the above configuration, the infrared light emitted from the light source 1 is transmitted to the condenser lenses 2 and 3, the measurement target plate 4, and the objective lens 6.
The light is focused on the fundus of the eye 9 to be examined.

The light reflected from the fundus of the eye is reflected by the mirror 11, passes through the relay lenses 12 and 13, and then forms an image on the light receiving element 17 by the imaging lens 16. The light receiving element 17 detects the incident light and supplies it as a digital signal to a microcomputer (not shown). When the measurement button (not shown) is pressed after the alignment for the eye 9 to be examined is completed, the microcomputer moves the measurement target plate 4 and the movable lens 15 until the position of the measurement target plate 4 is conjugate with the fundus of the eye 9 to be examined. At the same time, after the fixation target of the turret plate 22 forms an image on the fundus of the eye to be examined 9, the first relay lens is moved so that the fog is applied by an appropriate diopter.Then, the measurement light source 1 is moved. , the corneal reflection removal mask 14 and the measurement light receiving element 17 are moved 180 degrees around the optical axis.During rotation, the measurement target plate 4 and the moving lens 15 are moved by the signal from the light receiving element 17, and the measurement target plate 4 and the moving lens 15 are moved. The refractive power value for each meridian can be determined by the amount of movement. After completing the objective measurement as described above, when the switch for subjective measurement (not shown) is pressed, the microcomputer controls the The first relay lens 18 moves to the position of the value obtained in the visual measurement, and the cylindrical lenses 19 and 20 rotate respectively.Therefore, the visual acuity of the eye 9 to be examined is measured with the refractive power obtained in the objective measurement corrected. You will need to look at the optotype.

When the visual acuity measurement is completed, a contrast switching switch (not shown) is pressed and a contrast optotype is presented.

Then, perform a contrast test while changing the brightness of the background.

After this contrast test is completed, when a glare test changeover switch (not shown) is pressed, the glare lamp 5 on the measurement target plate 4 is turned on. At this time, the measurement target plate 4 is maintained at the position where the objective measurement has been completed, and the measurement target plate 4 and the turret plate 22 are both conjugate with the fundus of the eye 9 to be examined, so that the subject is not exposed to glare. You will be able to see the optotype in the glare of the light. Note that it may be moved to an optimal position based on the result of refraction measurement of the eye to be examined.

The optotype at this time may be a text chart or a striped optotype with a different background brightness. At this time, if the eye 9 to be examined has a cataract, the glare light is scattered due to the opacity of the crystalline lens, and visual acuity deteriorates, so that the examiner can know whether or not there is a cataract.

In addition, by maintaining the glare optotype at a position conjugate with the fundus of the eye 9 to be examined, glare light can always be projected with constant vision regardless of the state of the refractive power of the eye 9 to be examined. That is,
Eyes to be examined with different refractive errors can be tested under the same measurement conditions.

Furthermore, it goes without saying that the optical system is not limited to that of the embodiment, and that various types of optical systems can be used as long as the measuring light is narrowed down to a spot.

[Effects] According to the eye refractive power measurement device of the present invention, the loss of light amount can be minimized, and glare tests can be performed in a small space and at low cost, and can be useful for detecting cataracts.

[Brief explanation of drawings]

FIG. 1 is an optical layout diagram of the eye refractive power measuring apparatus of the embodiment, and FIG. 2 is a front view of a measurement target plate. 1... Light source for measurement 2.3... Condensing lens 4...
・Measurement target plate 5...Glare lamp 6.7...Objective lens 8.1
0... Beam splitter 9... Eye to be examined 11... Mira 12.13...
・Relay lens 14... Corneal reflection removal mask 15... Moving lens 16... Imaging lens 17...
・Measurement light receiving element 18...First relay lens 19.20...Cylindrical lens 21...Second relay lens 22...Turret plate 23...Condensing lens 24...Illumination lamp

Claims (4)

[Claims] (1) In an eye refractive power measuring device that projects a measuring target onto the fundus of the eye to be examined and detects the position of the target image to obtain refractive power information of the eye to be examined, for glare testing to be presented to the eye to be examined. An eye characterized by having an optotype and providing an illumination light source for glare light in the optical path of a measurement optotype projection optical system that projects the measurement optotype onto the fundus of the eye to be examined, thereby making glare testing possible. Refractive power measuring device. (2) An eye refractive power measurement device characterized in that the optotype for glare testing described in item 1 is placed on a turret board on which optotypes for visual acuity testing are arranged. (3) An eye refractive power measuring device characterized in that the illumination light source for glare light or the aperture provided on the subject side of the illumination light source according to item 1 is moved to a position substantially conjugate with the fundus of the eye to be examined. . (4) An eye refractive power measuring device characterized in that the illumination light source for glare light or the opening provided on the subject side of the illumination light source according to item 3 is provided on the measurement optotype plate.