JPS62268521A - Apparatus for measuring shape of cornea - 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 [Field of Industrial Application] The present invention relates to a corneal shape measuring device that projects a light source image onto the cornea of the object and measures the corneal shape based on the reflected corneal image.

[Prior Art] Conventionally, with this type of corneal shape measuring device, the measurement results are displayed numerically, and the direction of astigmatism must also be read numerically, so there is a risk of misreading or misunderstandings depending on the examiner. there were. In addition, in the corneal shape J+1 determination device for ophthalmic surgery, the measurement results are generally displayed outside the operator's field of view, so the operator must take his eyes off the eyepiece in order to see them. had the inconvenience of having to cancel the surgery. Furthermore, in the conventional case, when the reference direction of the corneal shape measuring device and the eye to be examined is misaligned, there is a problem that an error occurs in the astigmatism angle.

[Purpose of the Invention] In order to improve these conventional problems, the purpose of the present invention is to make it possible to display measurement results within the field of view of a microscope and to grasp the shape of the cornea visually. Another object of the present invention is to provide a corneal shape measuring device that does not cause an error in the astigmatic angle due to a deviation between the reference direction of the object and the measuring device.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide a means for measuring the shape of the cornea and controlling the lighting of a plurality of light sources arranged on the circumference based on the measurement results based on the Jllllll settings. A corneal shape measuring device characterized by comprising: means for displaying a lighting state of the light source within a field of view.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows an embodiment in which the present invention is applied to a surgical microscope 1, in which 2 is a light source box, 3 is a light source lighting control device, 4 is a known corneal shape measuring device, 5 is a measurement switch,
K represents the cornea of the eye to be examined. And light source box 2
, a large number of light sources A1 and A2 are used as illustrated in FIG.
, A3, . . . are arranged at equal intervals on the same circumference.

When measuring the shape of the cornea, all of these light sources A are turned on. As a result, as shown in FIG. 3, these light source images F1, F2,
F3, . . . are projected.

Therefore, when a surgeon looking through the surgical microscope 1 and performing a surgery steps on the measurement switch 5, the corneal shape measuring device 4 performs a measurement, and the light source lighting control device 3 controls the astigmatism according to the result of the III determination. The axial light source A is shown in Fig. 4(a)~
As shown in (d), the light blinks at a speed corresponding to the amount of astigmatism.

Figures 4 (a) to (d) are examples of light source control current waveforms showing blinking conditions depending on the degree of astigmatism; (a) shows when the amount of astigmatism is large, and (d) shows when there is no astigmatism. If it can be considered, (b) and (C) indicate intermediate cases. When the corneal shape 411 is continuously determined, the blinking direction and blinking speed of the light source A also change continuously.

Although the above-mentioned embodiment shows the case where the light source A blinks in the astigmatic axis direction, it can also be made to blink at a speed corresponding to the radius of curvature of the cornea in all meridian directions. Furthermore, although this embodiment shows a case where the blinking speed of light source A is changed depending on the amount of astigmatism, the number of blinks may be changed, or the brightness of light source A may be changed. .

Therefore, the brightness of the light source A may be changed in all meridian directions according to the radius of curvature of the cornea.

Note that it is also possible to obtain an optical signal by shielding the light source A according to the curvature in each meridian direction. Furthermore, in the above-mentioned embodiment, as the radius of curvature approaches a constant value, the speed of blinking becomes slower, but it is possible to provide a means for the examiner to set the curvature and rate of change in speed at which the blinking stops. It is also possible to increase the blinking speed as the radius of curvature approaches a constant value. Further, in the above-described embodiment, the optical signal indicates the astigmatic axis direction, but the optical signal may indicate a fixed direction, for example, a perpendicular direction to the astigmatic axis direction.

FIG. 5 shows a light source section in another embodiment of the invention. In the embodiment described above, a large number of light sources A are used as shown in FIG. 2, but in the case of FIG. The light is shielded by a light shielding means such as a liquid crystal shutter, and an optical signal is generated. In FIG. 5, B1 and 87 of the sections B1, B2, B3, . . . of the annular light source 6 are in a shielded state.
It works in the same way as the one in Figure 2.

In the case of the embodiment shown in FIG. 5, it is also possible to set the shielding direction in the astigmatic axis direction and to change the size of the shielding portion according to the astigmatic power. Furthermore, the shielding direction may be set in a constant direction with respect to the astigmatic axis, and the shielding may be repeated at regular intervals, and the repetition rate may be changed according to the astigmatic power. It is also possible to shield the light source 6 according to the radius of curvature.

FIG. 6 shows yet another embodiment. In the embodiment described above, the corneal reflection image of the eye to be examined is used as the optical signal within the visual field of the examiner, but the optical signal may also be obtained by direct light from the light source.For example, as shown in FIG. As shown in the figure, the examiner may directly observe the light sources C1, C2, C3, etc. provided within the examiner's field of view, or a character display provided outside may be used as a light deflector to direct the examiner's field of view. It can also be guided inward.

[Effects of the Invention] As explained above, the corneal shape measuring device according to the present invention has the following effects:
For example, when incorporated into a surgical microscope, the measurement results can be displayed within the field of view of the microscope, allowing the surgeon to continue the surgery while viewing the measurement results while looking into the surgical microscope. Furthermore, since the direction of astigmatism does not change due to the tilt of the subject and the corneal shape measuring device, there is no error in the astigmatic angle as in the conventional method, and it is also possible to grasp the corneal shape intuitively. This makes it possible to prevent reading errors and misunderstandings that tend to occur when reading the astigmatism direction numerically.

[Brief explanation of the drawing]

The drawings show an embodiment of the corneal shape measuring device according to the present invention, and FIG. 1 is a schematic diagram of the embodiment applied to a surgical microscope, FIG. 2 is an explanatory diagram of an example of arrangement of a light source, and FIG. 3 is an explanatory diagram of a corneal reflection image, Fig. 4 is a waveform diagram of the light source control current, Fig. 5 is an explanatory diagram of another embodiment of the light source, and Fig. 6 is a detection diagram when obtaining an optical signal by direct light from the light source. FIG. 1 is a surgical microscope, 2 is a light source box, 3 is a light source lighting control device, 4 is a corneal shape measuring device, 5l-)IId'
;:Bonno 2≦−C;ノ+coT! −te → +−v−,
m^1^9^9..., C1, C2, C3,... are light sources. Patent applicant: Canon Corporation Figure 1 Figure 32 Figure 5 7 B6 Shade 2 Figure b Figure 4 Figure 6 E' C6

Claims (1)

[Scope of Claims] 1. means for measuring the shape of the cornea; means for controlling the lighting of a plurality of light sources arranged on the circumference based on the measurement results by the measuring means; and controlling the lighting state of the light sources within the visual field. A corneal shape measuring device characterized by comprising: means for displaying. 2. The corneal shape measuring device according to claim 1, wherein the light source blinks in a predetermined direction with respect to the astigmatic axis. 3. The corneal shape measuring device according to claim 2, wherein the blinking speed of the light source is changed according to the astigmatic power. 4. The corneal shape measuring device according to claim 2, wherein the blinking rate of the light source and the rate at which the blinking rate changes are set by the examiner. 5. The corneal shape measuring device according to claim 1, wherein the light source blinks in number according to the astigmatic power. 8. The corneal shape measuring device according to claim 1, wherein the light source blinks at a blinking speed according to a radius of curvature in each meridian direction. 7. The corneal shape measuring device according to claim 6, wherein the corneal shape at which the light source stops blinking is set by the examiner. 8. The corneal shape measuring device according to claim 1, wherein the light source has a brightness corresponding to an astigmatic power corresponding to an astigmatic axis. 9. The corneal shape measuring device according to claim 1, wherein the light source has a brightness that corresponds to the radius of corneal curvature of the eye to be examined in each meridian direction. 10. The corneal shape measuring device according to claim 9, wherein the brightness of the light source is obtained by shielding the light source. 11. The corneal shape measuring device according to claim 1, wherein the light sources on the plurality of sides are one annular light source partially shielded. 12. The corneal shape measuring device according to claim 11, wherein a liquid crystal shutter is used as means for partially shielding the annular light source. 13. The corneal shape measuring device according to claim 11, wherein the direction of the shielding portion is in the astigmatic axis direction, and the size of the shielding portion is changed according to the astigmatic power. 14. The corneal shape measuring device according to claim 11, wherein the shielding is repeated at regular intervals, the shielding direction is set in a constant direction with respect to the astigmatic axis, and the repetition rate is changed according to the astigmatic power. .