JPS62224350A - Medical binocular microscope - 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 [Industrial Field of Application] The present invention relates to a medical binocular microscope used, for example, in ophthalmology for surgery.

[Prior Art] In ophthalmic surgery and the like, it is often necessary to obtain the radius of corneal curvature at the same time as recording images using a TV camera. Conventionally, in such cases, the image recording and measurement optical systems were provided as separate devices, but this had the disadvantage of complicating the m-structure.

[Object of the Invention] An object of the present invention is to provide a small and easy-to-use medical binocular microscope that incorporates an image recording mechanism and a measurement optical system within a surgical microscope system.

[Summary of the invention] The gist of the present invention is to achieve the above objects.

A light source for corneal curvature measurement provided at least around the objective lens; a light splitting member provided in the observation optical path after the objective lens to guide a portion of the light flux to the imaging member; and an optical system from the eye to be examined to the imaging member. The diaphragm is provided near the rear focal point, and the signal from the imaging member is time-divided to obtain an image of the eye to be examined and the light source image position data for measurement, and the radius of corneal curvature is determined while recording the image. This is a medical binocular microscope with the following characteristics.

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

FIG. 1 shows its configuration, in which an objective lens 1 is provided at a position facing the eye E to be examined, and 2
The variable magnification lens 2a is symmetrically arranged along the two stereoscopic observation optical paths.
2b, and eyepiece lenses 3a and 3b are arranged. Also,
Around the objective lens 1, as shown in FIG.
d are arranged at equal angles. A light splitting member 5 is inserted between the variable magnification lens 2b and the eyepiece lens 3b on one optical path. On the side of the light splitting member 5 that reflects the light beam from the direction of the objective lens 1, there is an optionally replaceable filter 6.6' with different transmission characteristics, an imaging lens 7, an aperture 8.
The imaging members 9 are sequentially arranged. Further, an imaging lens lO1 display means 11 is provided on the side of the light splitting member 5 that reflects the light beam from the eyepiece lens 3b side.

The examiner can look into the eyepieces 3a and 3b with his right and left eyes, H, and view the subject's eye E in three dimensions. The light sources 4a to 4d form images 4a' to 4d' on the cornea of the eye E to be examined. Here, a part of the light flux that has passed through the objective lens l passes through the variable magnification lens 2b, is reflected by the light splitting member 5, passes through the filter 6, the imaging lens 7, and the aperture 8, and reaches the imaging member 9. For example, an image pickup tube or a two-dimensional area sensor array is used as the image pickup member 9, and the image reflected on the image pickup member 9 is
As shown in the figure. FIG. 3(a) is an image of the anterior segment of the subject's eye E, which is for recording, and FIG. 3(b) is an image of the corneal reflection image 4a' to 4d', which is for measuring the radius of curvature. ” is shown in the photo.

The imaging member 9 is preferably sensitive to visible light and near-infrared light, the filter 6 is a visible light-transmitting filter and is used for the front image recording shown in FIG. 3(a), and the filter 6° is a near-infrared light The external light transmitting filters are used for the measurement shown in FIG. 3(b), and these filters 6.6 degrees are inserted and removed alternately in synchronization with the blinking of the light sources 4a to 4d. By dividing recording and measurement into visible light and near-infrared light in this way, there is no loss of light quantity, and the anterior segment image does not overlap with the measurement light source image, making signal processing easier.

The diaphragm 8 is required for the measurement shown in FIG. 3(b), and may be removed to increase the amount of light when recording the image shown in FIG. 3(a).
If the chief ray of is set so that it diverges by several degrees,
It is possible to make it almost unaffected by errors in the working distance.

That is, when the working distance changes, the light source images 4a'' to 4d'
It is possible to prevent measurement errors from occurring due to changes in the intervals between the two. The imaging lens 10 projects the measurement results displayed on the display means 11 onto the examiner's R through the light splitting member 5, and a mark for 7 alignments is provided here, so that the eye to be examined E can be clearly seen. It is also possible to perform alignment.

FIG. 4 shows a light source image 4 of near-infrared light reflected on the imaging member 9.
a” to 4d” are shown. As the radius of corneal curvature increases,
The four images 4a'' to 4d'' formed by the light sources 4a to 4d are spaced apart from each other, and become closer as the radius of curvature becomes smaller. When there is corneal astigmatism, rotation of the image position occurs, resulting in angles θ1 and θ2.
appears. When the alignment shifts, the images shift overall, but the relative positional relationship of the four images 4a'' to 4d'' does not change.The radius of the cornea and astigmatism are determined by the relative positions of the four images 4a'' to 4d''. It is determined. That is, images 4a''-4b'' and 4
It can be calculated based on the respective distances of b''*4c'' and the rotation angles θ1 and θ2 from the directions of the light sources 4a to 4d.

For example, to find the position of the image 4a'', etc., there is a method as shown in FIG. 5. FIG. The signal obtained by binarizing the signals from each scanning line at an appropriate level is shown in (b).
Shown below. These binarized information are temporarily stored, and the center coordinate position of the image 4a'' on the imaging member 9 can be calculated and determined from this data.

FIG. 6 shows another embodiment of the present invention, in which measurement light sources 4e to 4h are provided on the examiner's silver side and R side of the objective lens 1 in an oblique direction that does not interfere with the left and right eye optical paths. It is designed to irradiate the cornea.

As the measurement light source, a plurality of point light sources 4 are provided as in the embodiment,
The corneal shape may be determined from the relative position of the image, or may be determined from the shape of the image using a ring-shaped light source.

When point light sources are used as in the embodiment, there are three unknowns: the maximum and minimum radii of curvature and their directions, so at least three light sources are required.

Next, a processing circuit for signals output from the imaging member 9 will be explained with reference to FIG. In this FIG. 7, 20 is a TV camera as an imaging means, 21 is an observation monitor, and the observation monitor 21 is used to display the images in FIG. 3(a) and (b).
Display the statue of. 22 is a processor, 23 is an image memory, and the image memory 23 stores binarized data at an address corresponding to each pixel of the image pickup signal (b). Storing predetermined binarized data at each address of the image memory 23 is performed by the following configuration circuit. That is, the reference clock generation circuit 24. Scan synchronization system frequency divider circuit 25
generate pixel transfer lock, data transfer lock, horizontal synchronization signal, and vertical synchronization signal, respectively. Here, the pixel transfer lock frequency is set to a frequency that is approximately equivalent to the time pitch of the horizontal scanning resolution of the TV left camera 0. The binarization circuit 26 compares and discriminates the output signal of the TV left camera 0 with an arbitrary reference level and outputs a binarized signal. This binarized signal is input to the shift register 27, bit-shifted every pixel transfer lock cycle, and converted into bit-parallel binarized data.

On the other hand, the processor 22 is configured to output updated addresses one by one to the image memory 23 each time it receives a data transfer lock, so that the binary data is transferred to the image memory 23 via the data buffer 28. is input and storage begins. Further, when the processor 22 counts data transfer locks and finishes updating a predetermined address,
It is determined that the data transfer for one screen has ended, and the image memory 23 is placed in the storage holding mode.

Next, the processor 22 reads out the binarized data held in the image memory 23, and converts the data into images 4a", 4b", 4c", and the like using the method shown in FIG.
4d" (7) Calculate the center position of each point, calculate the distance of each point, and calculate the amount of deviation from the reference coordinates. From these results, calculate the degree of corneal astigmatism in the radius of curvature of the cornea and the corneal astigmatism axis angle. The calculation results are displayed on the display 29.

In the above embodiment, the TV left camera 0 is used as the imaging signal.
However, the bandwidth of the color-processed video signal is generally limited to about 3 MHz, and the imaging resolution of the corneal reflection image may be slightly insufficient. In this case, by using the luminance signal before the colorization process in the TV left camera 0 as the image capture signal for the binarization process, it is possible to perform signal processing that utilizes the upper limit of the resolution of the image capture member.

[Effects of the Invention] As explained above, the medical binocular microscope according to the present invention shortens the working distance of the objective lens by inserting a half mirror for measurement on the side of the eye to be examined of the objective lens. It is compact and efficient, allowing measurement information to be obtained along with recording images during a single surgery.

[Brief explanation of drawings]

The drawings show an embodiment of the medical binocular microscope according to the present invention, with Fig. 1 showing its configuration, Fig. 2 showing the arrangement of the objective lens and measurement light source, and Figs. 3 (a) and (b) showing the arrangement on the imaging member. Fig. 4 is an explanatory diagram of the anterior segment image and measurement light source image, Fig. 4 is an explanatory diagram of the measurement light source image, Figs. 5(a) and (b) are explanatory diagrams of the light source image on the scanning line and the binary signal, FIG. 6 is a layout diagram of an objective lens and a measurement light source according to another embodiment, and FIG. 7 is a block circuit configuration diagram of an electrical signal processing system. Reference numeral 1 is an objective lens, 2a and 2b are variable magnification lenses, 3a,
3b is an eyepiece L/7 lens, 4a and 4b are light sources, 5 is a light splitting member, 6.6'' is a filter, 7°10 is an imaging lens, 9 is an imaging member, 11 is a display means, 20 is a TV camera, 21 is an observation monitor. 22 is a processor, 23 is an image memory, and 29 is a display device. Patent applicant: Canon Corporation Fig. 1 Fig. 4 Fig. 5 4D'"

Claims (1)

[Scope of Claims] 1. A light source for corneal curvature measurement provided at least around the objective lens, a light splitting member provided in the observation optical path after the objective lens to guide a part of the light flux to the imaging member, and a light source provided from the eye to be examined. an aperture provided near the rear focal point of the optical system up to the imaging member, and time-sharing the signal from the imaging member to obtain an image of the eye to be examined and the light source image position data for measurement; A medical binocular microscope characterized by recording images and determining the radius of corneal curvature. 2. The medical binocular microscope according to claim 1, wherein the time division is performed by replacing and inserting a visible light transmission filter and a near-infrared light transmission filter in front of the imaging member.