JPS5875529A - Self-feeling ascertaining apparatus astigmatic axis in objective automatic refraction meter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an objective automatic refractometer that allows the subject's eye to view an astigmatic axis confirmation chart after the measurement is completed, thereby allowing the subject's eye to confirm the astigmatism axis by consciousness.

In the conventional noodle device, infrared rays are emitted from the pupil of the eye to be examined, and the light energy reflected from the fundus of the eye is used to determine the spherical refractive power,
Measurements of cylindrical refractive power and axial angle have been made objectively and automatically, but there are various problems with measurement accuracy. In order to ensure measurement accuracy with this type of device, it is desirable that the pupil diameter of the eye to be examined be approximately 0.3 ff or more during measurement, and if it is less than this value, a measurement error will occur. However, since measurements are usually performed in a bright room, the way the pupil of the eye to be examined opens differs depending on the surrounding brightness or depending on the person. Furthermore, it is often not possible to guarantee a pupil diameter of 0.3 mm depending on the condition of the eyelids and eyelashes of the eye being examined.

In particular, the astigmatic axis angle is easily affected by this.

The purpose of this invention is to eliminate the above-mentioned drawbacks, and after the refractive power measurement is completed, the astigmatism axis confirmation chart is moved to a position corresponding to the refractive power value of the subject's eye, and the test subject is asked to look at the chart. By doing so, you become aware of the astigmatic axis angle.
・It was heated to ℃ for confirmation.

The present invention will be explained in detail below with reference to the drawings.

・Figure 1 is a layout diagram of the measurement optical system of the refractometer according to the present invention, and 1 is a measurement light source having a wavelength in the infrared region;
It is arranged almost at the focal point of the condensing lens 2. 3 is a spot diaphragm that is movable so as to be placed at a position conjugate with the fundus of the eye to be examined; 4 is an objective lens; 5 is a prism; and 6 is the eye to be examined. 7 is an objective lens, 8 is a prism, 9 is a first relay lens, 10 is a corneal reflection removal mask placed at a position conjugate with the cornea of the eye 6 to be examined, 11 is a second relay lens, and 12 is the spot diaphragm 3. 13 is an imaging lens.

Reference numeral 14 denotes a light receiving element for measurement, which rotates around the optical axis in synchronization with the measurement light source 1 and the corneal reflection removal mask 0. Reference numeral 15 indicates a visible light source, 16 indicates a condenser lens, 1
7 is a green filter, and 18 is an optotype plate projected onto the fundus of the eye to be examined 6, which is movable in order to provide 17 og to the eye to be examined. 19 and 2o are third and fourth relay lenses, and 21 is a reflecting mirror.

FIG. 2 is a plan view of the optotype plate 18, and its target is an astigmatic axis confirmation chart as shown. The numbers around the target indicate the axis angle.

With the above configuration, the infrared light emitted from the light source 1 passes through the condenser lens 2, spot diaphragm 3, objective lens 4, and prism 5, and is condensed onto the cornea of the eye 6 to be examined. reach.

On the other hand, the light from the visible light source 15 passes through a condensing lens 16 and a green filter 17, projects a chart for self-awareness confirmation on an optotype board 18 onto the fundus of the eye 6 to be examined, and causes the eye 6 to fixate.

The light reflected from the fundus of the subject's eye 6 passes through prisms 5 and 8.
The reflected light passes through the corneal reflection removal mask 10 and is imaged onto the light receiving element 14 by the imaging lens 13. When the measurement button (not shown) is pressed after the alignment for the eye 6 to be examined is completed, the spot diaphragm 3 and the moving lens 12 move to a position where the position of the spot diaphragm 3 is conjugate with the fundus of the eye 6 to be examined.
At the same time, the optotype plate 18 moves to a position corresponding to the refractive power of the eye 6 to be examined, and then moves to the + side by an appropriate diopter to apply fog to the eye 6 to be examined. Thereafter, the measurement light source 1, the corneal reflection removal mask 10, and the measurement light receiving element 14 rotate the optical axis by 18σ to measure the spherical refractive power, cylindrical refractive power, and axial angle of the eye 6 to be examined.

During this measurement, if the pupil of the eye to be examined 6 is constricted to below a predetermined diameter due to the influence of external light, or if the eyelids or eyelashes are below this diameter, the corneal reflection removal mask 10 may The reflected light from the cornea, eyelids and eyelashes, which cannot be removed, enters the light receiving element 14, resulting in a measurement error. In particular, the astigmatic axis angle is easily affected by this. After the measurement is completed, the optotype plate 18 returns to the position corresponding to the refractive power of the eye 6 to be examined.

The subject is then asked to read the angle corresponding to the most clearly visible radial line and compare it with the value displayed on the device.

As is clear from the above description, according to the present invention, the objective measurement can be subjectively confirmed after the measurement is completed, so that the reliability of the measurement result is further increased.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a measuring optical system of a refractometer according to the present invention, and FIG. 2 is a drawing showing an astigmatism axis confirmation chart. (1)... Light source for measurement (3)... Spot aperture (6)... Eye to be examined (10)... Corneal reflection removal mask (14)... Light receiving element for measurement (15)...・Visible light source (18) ・Visible light source (18)

Claims (1)

[Claims] In an objective automatic refractometer that irradiates light energy onto the eye to be examined and measures the refraction of the light energy reflected from the fundus, the astigmatism axis confirmation chart is used to identify the target on the optotype board that the eye to be examined looks at. Just before measurement, move it to a position corresponding to the refractive power value of the eye to be examined, then move it to the + side to give fog to the eye to be examined, and then return it to the position corresponding to the refractive power value after measurement. A self-confirmation device for the astigmatic axis in an objective automatic refractometer.