JPS59105436A - Medical endoscope - 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 a medical and surgical microscope, and more particularly to a microscope equipped with a measuring device that automatically measures corneal curvature.

Eye surgery is often performed while looking through a microscope, but when suturing the affected area in corneal surgery, the radius of curvature of the corner H is measured and the degree of suturing is adjusted according to that measurement. There is. Although a manual keratometer is built into a microscope for such use, it is extremely troublesome to operate the keratometer while performing surgery.

An object of the present invention is to provide a microscope equipped with a device that can automatically measure the curvature of the cornea. However, if the observation light for observing the affected area is incident on the photoelectric detection means for automatic measurement, accurate measurement will be hindered. One way to solve these difficulties is to time-divide the time of measurement and observation, but the present invention aims to eliminate the above-mentioned difficulties while maintaining continuity of observation.

Hereinafter, the present invention will be described in detail with reference to the drawings.

In FIG. 1, E is the eye to be examined and C is its cornea. (2) is an illumination light source, such as a halogen bulb. 2 is a wavelength cut filter that has the effect of blocking light with longer wavelengths than near-infrared light and transmitting light with shorter wavelengths, thereby removing near-infrared light from the light emitted from light source 1. can do. 3 is a collimator lens, which is useful for uniformly illuminating the area to be examined. The light source 1, wavelength cut filter 2, and collimator lens 3 described above constitute an observation illumination system.

Next, 5 is an objective lens with a large diameter of 10, and 6 and 7 are relay lenses, and the optical axes of the relay lenses 6 and 7 are arranged in parallel. 8 and 9 are eyepiece lenses for binocular vision, and relay lenses 6 and 7
It is useful to visually check the images. The second objective lens 5, relay lenses 6 and 7, and eyepiece lenses 8 and 9 constitute a corneal observation system.

Furthermore, 10 is a dichroic mirror, which has the function of reflecting light on the longer wavelength side than near-infrared light and transmitting light on the shorter wavelength side, so that near-infrared light can be selected. The dichroic mirror 10 is installed obliquely on one optical path of the corneal observation system. 11 is an imaging lens. Reference numeral 12 denotes a wavelength transmission filter, which has the function of transmitting near-infrared light. However, if the dichroic mirror has high wavelength separation performance, the filter 12 can be omitted, or a semi-transparent mirror can be used instead of the dichroic mirror. 13
is a photoelectric converter for two-dimensional imaging, for example, CCD (Ch
A solid-state image sensor such as a large coupled device is used. The above objective lens 5, relay lens 7, dichroic mirror 10, imaging lens 11,
The filter 12 and the photoelectric converter 13 constitute a light receiving section of the corneal curvature measuring device. Further, l is a ring-shaped light source, which uses a ring-shaped xenon flash discharge tube to constitute the illumination system of the measuring device.

First, the operation of the corneal curvature measuring device will be explained.

In FIG. 1, the ring-shaped light source 14 forms a reflected image 14 (virtual image) by the cornea C of the eye E to be examined. This reflected image 14' is formed as a projected image 14 (FIG. 2) onto the photoelectric converter 13 by the projection system (5, 7, 10, 11). The ring-shaped light source 14 as a projection index may be one in which a plurality of light sources are provided on a circumferential ball, or a ring-shaped slit may be provided in the optical path as a projection index. Here, since the cornea C is generally regarded as a toric surface, the ring-shaped light source 1
Even if 4 is a perfect circle, the corneal reflection image 14 will be an ellipse. Further, from this, the projected image 14 by the projection system becomes an ellipse.

A projected image 14 projected onto the photoelectric converter 13 in FIG. 2,
Three appropriately spaced scan lines 15.16.1 across this
7 intersects with the projected image 14 1515.16, 16, 1
7.17 is found. The corneal curvature of the eye to be examined is calculated by determining the elliptical shape of the projected image 14 from the coordinates of five of these intersection points.

Generally, the elliptic equation can be expressed as ax2+by+2cxy+dx+ey+1=0 for any coordinate axis X+V. Here, five of a to e are unknown numbers.

From this, it is understood that the shape of an ellipse on a plane is determined by the coordinates of five points, and that a minimum of three scanning lines can be used.

Returning to FIG. 1, when the light source 1 is turned on, the light in the visible wavelength range of the light emitted from the light source 1 passes through the filter 2 and uniformly illuminates the cornea C via the lens 3. The scattered reflected light from the cornea C is converged by the objective lens 5, and is further imaged by the relay lenses 6 and 7, respectively. These images have parallax and the objects are observed through each eyepiece 8.9.

At an appropriate point in time, the ring-shaped light source 14 is turned on instantaneously, the light coming from it illuminates the cornea C, the light reflected by the cornea C is converged by the objective lens 5 and the relay lens 7, and then is convergently When reflected by the mirror IO, light with wavelengths longer than near infrared is reflected, and a ring-shaped virtual light source image 14' is formed on the photoelectric converter 13 by the imaging lens 11. Of the visible light reflected by the cornea C, visible light with wavelengths shorter than near-infrared passes through the dichroic mirror 10 and therefore does not reach the photoelectric converter 13. Even if some visible light is reflected by the dichroic mirror, Since the light is also blocked by the filter 12, it does not become noise during photoelectric conversion. Note that the values related to the corneal curvature (curvature in the long axis and short axis directions and axis angle) calculated based on the information detected by the photoelectric converter 13 may be displayed on the outside of the device, or may be displayed on the relay. The image may be displayed on the periphery of the image forming plane formed by the lens 6 toward the eyepiece 8 .

According to the present invention described above, the affected area can be observed under a microscope and the automatically measured value of the corneal curvature can be confirmed, which has the effect of freeing the user from the trouble of performing measurements manually. Automatic measurements are also protected from noise factors, so
Accurate measurements can be obtained.

On the other hand, if a strobe is used as the measurement light source, the measurement can be carried out instantaneously, or if a dichroic mirror is used as the light splitter placed in the optical path, there is an advantage that the observation field of view will not be obscured.

[Brief explanation of drawings]

FIG. 1 is an optical sectional view showing an embodiment of the present invention. FIG. 2 shows the photoelectric converter and its projected image. In the figure, 1 is an illumination light source, 2 is a near-infrared cut filter, and 3 is a near-infrared cut filter.
is a collimator lens, 5 is an objective lens, 6 and 7 are relay lenses, 8 and 9 are eyepiece lenses, 10 is a dichroic mirror, 11 is an imaging lens, 12 is a near-infrared transmission, visible cut filter, and 3 is a photoelectric conversion It is a vessel. Applicant Canon Co., Ltd.

Claims (5)

[Claims] (1) An observation system for observing the subject, an observation illumination system for illuminating for observation, and a measurement device including a photoelectric detector and a corneal illumination system for measuring the radius of corneal curvature; A medical device characterized by being provided with a removing means for removing light of a predetermined property from illumination light from an observation illumination system, and a regulating means for regulating light incident on a photoelectric detector to only light of a predetermined property. microscope. (2) The medical microscope according to claim 1, wherein the light having a predetermined property is near-infrared light. (3) The medical microscope according to claim 1, wherein the regulating means is a guichroic mirror that separates near-infrared light and visible light by reflection and transmission. (4) The medical microscope according to claim 1, wherein the corneal illumination system includes a phosphorescent flash discharge tube. (5) The medical microscope according to claim 1, wherein the regulating means is a guichroic mirror that reflects near-infrared light and transmits visible light, and is installed obliquely in the optical path of the observation system.