JPH0417046B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a subjective eye refractive power measurement device, and more specifically, a focus detection chart is projected onto the fundus of the eye by a plurality of light beams, and a plurality of light beams are projected onto the fundus of the eye. The present invention relates to a subjective eye refractive power measuring device in which a subject consciously detects the positional deviation and coincidence of the chart images and the in-focus state.

[Prior art]

Examples of conventional subjective eye refractive power measuring devices include:
Project the eye refractive power measurement chart onto the fundus of the subject's eye using a projection lens system, and project the chart to a position where the chart image is focused on the fundus of the subject's eye, that is, a position where the subject can clearly see the chart. Move it on the optical axis of the lens system. For this adjustment, there is a method that measures the eye refractive power by detecting in which direction and by how much the chart has moved from a reference position corresponding to a diopter of 0.

Another example of the conventional subjective eye refractive power measurement device is that in the above conventional example, instead of moving the chart on the optical axis, lenses with different refractive powers are selectively inserted on the optical axis. Some devices are configured to measure the eye refractive power from the refractive power of the lens.

However, with the conventional apparatus described above, it is necessary to judge whether or not the chart image is focused on the fundus of the examinee's eye based on the degree of blur in the chart image, but this judgment is difficult for the examinee. Therefore, high precision measurements could not be expected.

In yet another example of a conventional subjective eye refractive power measuring device, in order to solve the problems of the conventional device described above, the light beam from the chart is passed through a two-hole diaphragm placed at a position conjugate with the pupil of the patient's eye. There is one that is configured to project onto the fundus of the eye. This means that when the light beam from the chart is focused on the fundus of the examinee's eye,
When the two chart images are aligned and formed on the fundus of the subject's eye, but are not in focus, the two chart images are formed separately, so the in-focus state of the chart images can be easily and accurately determined. This is a so-called matching type subjective refractive power measuring device.

However, in the above-mentioned matching type subjective refractive power measuring device, in order for the measurement light flux that has passed through the two-hole diaphragm to pass through the pupil of the subject's eye, so-called alignment adjustment is performed to match the optical axis of the measuring device and the optical axis of the subject's eye. This posed the problem of difficult measurement operations.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems of conventional subjective refractive power measuring devices, and provides a subjective refractive power measuring device that can easily measure refractive power with high precision without requiring the above-mentioned alignment adjustment. The purpose is to provide.

[Structure of the invention]

In order to achieve the above object, the present invention has the following configuration. That is, the structural features of the present invention include: a light source section including a plurality of light sources; a chart for measuring eye refractive power that is illuminated by the light beam from the light source section; and a chart for measuring eye refractive power that is illuminated by the light beam from the chart; a projection lens system for projecting a Hechaert image, the illumination light source section is arranged at a position substantially conjugate with the pupil of the eye to be examined, and the plurality of light sources cover an area wider than the pupil of the eye to be examined. , and are arranged and configured so that two or more light source images are always included within an area corresponding to the pupil of the eye to be examined.

〔Example〕

As shown in FIG. 1, the embodiment of the present invention consists of an optical system R for the right eye to be examined and an optical system L for the left eye to be examined,
Both optical RLs have the same configuration. The optical axes LO of the right optical system R for the eye to be examined and the optical system L for the left eye to be examined,
A light source plate 18 is provided on the RO and is arranged in a conjugate positional relationship with the eye 22 and pupil 26 to be examined, and on which a plurality of light sources 16 such as light emitting diodes are arranged. On the side of the eye to be examined 22 of the light source plate 18, there is a relay lens 2 that relays the light beam from the light source 16.
0 is placed.

A cross mark 1 is located on the side of the eye 22 of the relay lens 20 and near a position conjugate with the fundus 19 of the eye to be examined.
A chart plate 14 having a chart plate 2 is disposed so as to be movable on the optical axes LO and RO. A projection lens 24 is further arranged on the eye 22 side of the chart board 14 for projecting the cross mark 12 illuminated by the light source 16 onto the fundus 19 of the eye to be examined. The projection magnification of the projection lens 24 is set such that, as shown in FIG. 2, when the light source plate image 18' is projected onto the pupil 26 of the eye to be examined, for example, four light source images 16' are included in the pupil 26 of the eye to be examined. It can be decided.

In the above configuration, when the cross mark 12 is moved to a position conjugate with the fundus 19 of the eye to be examined, only one image of the cross mark 12 is formed on the fundus 19 of the eye to be examined; When the fundus 1 of the eye to be examined is moved to a position that is not conjugate with the fundus 19 of the eye to be examined.
Images of a plurality of cross-shaped index images 12 illuminated by a plurality of light sources 16 are formed on 9 .

Here, as shown in FIG. 2, the light source image 16 is formed on the pupil 26 of the eye to be examined over an area approximately 10 times the area of the pupil 26 of the eye to be examined.
The light source image 16 is formed on the pupil 26 of the subject's eye even if the center of the light source 6 is far away from the optical axes LO and RO. That is, even if the center of the pupil 26 of the examinee's eye is considerably deviated from the optical axes LO, RO, the plurality of cross marks 16' illuminated by the plurality of light sources 16 are imaged on the fundus 19 of the examinee's eye. Therefore, so-called alignment adjustment for aligning the optical axis of the measuring device and the optical axis of the eye to be examined, which was performed in conventional devices, is not necessary.

In the apparatus described above, the chart plate 14 is moved on the optical axes LO and RO in order to focus and form the image of the cross mark 12 on the fundus 19 of the eye to be examined. In the movement adjustment described above, the chart plate 14 may be moved to a position where the imaging light beam of the cross index image 12 is focused at infinity. When there is a refractive power, the position of this chart plate 14 is taken as a reference position in which the refractive power is 0. When the chart plate 14 is moved and adjusted to focus the image of the cross mark 12 on the fundus of a given eye, the amount of movement of the chart plate 14 from the reference position indicates the refractive power.

Here, if the focal point 21 of the relay lens 20 on the side of the eye to be examined 22 is configured to be in a conjugate position with the pupil of the eye to be examined 26 formed by the projection lens 24, the chart board 1
4 from the reference position is directly proportional to the principal point refractive power of the eye to be examined. On the other hand, if the focal point 21 of the relay lens 20 is configured to be in a position conjugate with the position of the glasses worn by the projection lens 24, the chart board The moving distance of 14 from the reference position is directly proportional to the refractive power of the eye to be examined.

〔Effect of the invention〕

Since the present invention is configured as described above, the target projection light flux arrives over a wide range on the pupil of the eye to be examined, and the so-called alignment adjustment that aligns the optical axis of the measurement device with the optical axis of the eye to be examined during measurement is substantially performed. This is not necessary and has the effect of efficiently measuring refractive power. For example, according to experiments conducted by the present inventor, alignment adjustment that conventionally required a range of ±0.5 mm can be measured within a range of ±10.0 mm using the device of the present invention. Generally, measurements can be made by looking normally through the eyepiece of the measuring device. The large allowable range of alignment adjustment has the advantage that interpupillary distance adjustment can be made unnecessary, especially in an apparatus that simultaneously measures the refractive power of both eyes as in this embodiment.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the optical configuration of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the pupil of the eye to be examined and the light source. RO, LO...Optical axis, 14...Chart board, 16
... light source, 18 ... light source plate, 19 ... fundus of the eye to be examined, 20 ... relay lens, 21 ... pupil of the eye to be examined,
24...Projection lens.

Claims (1)

[Claims] 1. A light source section comprising a plurality of light sources, a chart for measuring eye refractive power illuminated by the light flux from the light source section, and a projection lens system for projecting a chart image onto the fundus of the eye to be examined using the light flux from the chart. The illumination light source section is arranged at a position substantially conjugate with the pupil of the eye to be examined, and the plurality of light sources are always located in an area wider than the pupil of the eye to be examined, and within an area corresponding to the pupil of the eye to be examined. 1. A subjective eye refractive power measurement device, characterized in that it is arranged and configured to include three or more light source images.