JPH0759231B2 - Anterior segment cross-section imaging device - Google Patents

Description

Detailed Description of the Invention a. The present invention relates to an anterior ocular segment cross-section imaging apparatus for projecting slit light onto the anterior ocular segment and taking an image from a direction at an angle to the slit light.

B-2. Prior art When the object plane is tilted with respect to the optical axis of the photographing optical system, the image plane,
By inclining the image plane and the main plane of the lens so that the respective extension planes of the object plane and the main plane of the lens intersect at one line of intersection, the entire surface of the object can be focused on the image plane. The principle is known. An example of a crystalline lens cross-section photographing apparatus that applies the Scheimpflug principle to a slit lamp, that is, a finder system, a slit projection system, and a photographing system is disclosed in, for example, JP-B-59-26298.
It is disclosed in the publication. Then, they take a slit image on a crystalline lens while looking through a slit lamp finder, and take a photograph of the illumination area obliquely.

A-3. Problems to be Solved by the Present Invention However, since the alignment in the conventional device is performed by the slit image on the cornea while looking through the finder, the alignment cannot be accurately performed. In particular, the alignment from the optical axis direction is not accurate, so that the observation system can be switched to observe from the cross-section imaging system, but the alignment takes time.
Further, since the slit projection optical axis and the visual axis coincide with each other, the subject sees the slit projection system, and it is difficult to fix the subject at the same time as being dazzling and causing pain.

It is an object of the present invention to eliminate the drawbacks of the above conventional apparatus by adding an alignment fixation optical system to the slit projection system, the observation system and the photographing system.

B. Configuration of the invention b-1. Means for solving the problems In order to solve the above problems, the present invention projects slit light onto the anterior segment of the eye to be examined, and shines the optical cross section of the projected slit light. In an anterior ocular segment cross-section imaging apparatus for imaging with an imaging means arranged according to the principle of Plouke, an imaging means sensitive to an infrared region for imaging the anterior ocular segment of the eye to be examined from the front side, A display for displaying an eye image, a reticle forming means for forming an alignment reticle on the display screen, an index projecting means for projecting an alignment index for aligning the top, bottom, left, right, front and back onto an eye to be examined, Index forming means for forming an alignment index formed by the index projecting means on the display screen, and a visual guide for guiding the line of sight of the eye to be examined in a predetermined direction. An anterior ocular segment cross-section imaging apparatus characterized in that a line guiding means is arranged.

B-2. Embodiments The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an outline of an optical system of an anterior ocular segment cross-section imaging apparatus using the Scheimpflug principle. (1) is an illumination light source for projecting a slit image on the anterior ocular segment, and (2) is infrared transmission. Filters, (3) and (4) are condenser lenses, (5) is a flash light source for photography, (6) is a slit whose slit width can be changed like a normal slit lamp, and (7) is a slit. A polarizing filter for preventing light from entering the alignment CCD camera described later, (8) is a slit projection lens, (9) is a rectangular aperture stop for increasing the depth of focus of the slit projection image, and (10) is It is a polarizing beam splitter and forms a slit projection system from (1) to (10). (11) is the eye to be inspected, (12) is the anterior segment of the eye, (13) is the projection lens, (14) is the CCD camera,
The imaging system in (13) and (14) is formed. The optical cross section of the projected image of the slit (6), the main plane of the taking lens (13) and the extension plane of the image forming plane of the CCD camera (14) are arranged so as to intersect with one line of intersection. Further, in this embodiment, the slit projection optical axis and the photographing optical axis are arranged with an inclination of 45 °. (15) is a light source for alignment consisting of a visible light source such as LED, (16) is an index for fixation and alignment consisting of a pinhole as shown in FIG. 2, (17)
Is a lens for index projection, (18) is a half mirror,
(15) to (18) form an alignment fixation projection system. (19) is an imaging lens, (20) is a half mirror, (2
1) is a CCD camera for alignment and forms an alignment observation system with (19) to (21). (22) is a reticle projection light source composed of infrared light, (23) is a ring-shaped reticle for aligning as shown in FIG. 3, (24) is a reticle projection lens, and (20), (22) to (24) forms the alignment reticle projection system.

In addition, this device is designed so that the cross section of the anterior segment of the eye can be photographed at two or more places, and the above (1) to (10) and (13) to
The structure is such that (18) is rotated around the visual axis of the eye (11) to be examined.

Fig. 4 shows the monitor of the CCD camera (21), (16a) is a reflection image of the index for fixation and alignment on the anterior surface of the cornea,
(23a) shows an image of the alignment reticle.

With the above-mentioned structure, first, at the time of photographing, the image of the fixation and alignment indices (16) is taken into the eye (11) to be examined.
And project the image to the subject. Meanwhile, the index (1
The image reflected by the front surface of the cornea of 6) is formed on the alignment CCD camera (21) by the image forming lens (19). The photographer is C
While looking at the monitor of the CD camera (21), in order to put the point image (16a) of the index (16) within the small circle of the alignment reticle image (23a), the device is moved left and right and up and down to perform alignment. Alignment in the optical axis direction is performed by moving the device back and forth so that the point image (16a) becomes a clear image.

To focus the shooting system, look at the monitor (not shown) of the CCD camera (14) for shooting, or the shooting lens (13) or
The CCD camera (14) is moved along the optical axis while maintaining the Scheimpflug principle. In a normal case, since the F-number of the taking lens (13) is large, the depth of focus is deep, and there is almost no need to focus upon completion of alignment.

C. EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, fixation of the eye to be inspected is facilitated, and the accuracy of alignment can be improved even for an early patient with cataract. The property can be improved, and the change with time of turbidity can be accurately captured.

Further, according to the present invention, fixation of the eye to be inspected is facilitated, and accurate alignment of the slit incident position on the cornea is enabled. As a result, accurate alignment can be performed regardless of the progress of cataract.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an optical system showing an embodiment of the present invention, FIG. 2 is a fixation view and an alignment index, FIG. 3 is a plan view of an alignment reticle, and FIG. It is a front view of an alignment monitor. (6) …… Slit (12) …… Anterior segment of eye to be examined (13) …… Shooting lens (14) …… CCD camera for shooting (16) …… Indicator for fixation and alignment (21) …… Alignment CCD camera (23) …… Alignment reticle

Claims (2)

[Claims] 1. An anterior ocular segment cross-section imaging apparatus for projecting slit light onto the anterior ocular segment of an eye to be examined, and photographing an optical cross section of the projected slit light with an imaging means arranged according to the Scheimpflug principle. A photographing means for photographing the anterior segment of the eye from the front side, a display for displaying the anterior segment image of the subject's eye by the photographing means, and a reticle forming means for forming an alignment reticle on the display screen. Index projection means for projecting an alignment index for aligning the top, bottom, left, right, front and back onto the eye to be examined, and an index forming means for forming the alignment index formed by the index projection means on the display screen, An anterior ocular segment cross-section imaging apparatus, comprising: a visual line guiding means for guiding the visual line of the optometry in a predetermined direction. 2. An anterior ocular segment cross-section imaging apparatus, wherein the index projecting means of claim 1 includes a light source containing a luminous flux visible to an eye to be inspected, and the index also serves as a fixation light source.