JP2001231754A - Ophthalmometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely and simply measure the shape of the cornea including its periphery without irrespective of the motion of the eye of a subject. SOLUTION: A luminous flux from a visible semiconductor laser light source 36 is switched to the right and left by a double-side scanning mirror 30 to be projected on the cornea C of the subject E while scanning one step each time by a step motor 28, thereby reflected light from the cornea C forms an image at a video camera. This video is fetched to an arithmetic means by each rotation step of the mirror 30 to analyze the surface shape and the thickness of each part of the cornea including the peripheral parts of the cornea from a cornea scattered image. Then, an infrared LED light source emits light weakly to fetch also a cornea reflected image T which can be obtained by an array sensor simultaneously and the position of the eye E is recorded by each scattered image. It is calculated to detect the position of the eye E in fetching each scattered image to recognize which part of the cornea each scattered image is, thereby precise measurement of the shape is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optometric apparatus used in an ophthalmic hospital or an optician.

[0002]

2. Description of the Related Art Conventionally, an apparatus for measuring a corneal shape including the periphery by projecting a slit light beam onto a cornea and capturing a scattered image of the cornea, and an optometry for measuring a curvature near the center of the cornea based on the position of a corneal reflection image. Devices are known.

[0003]

However, in the conventional example described above, when the corneal shape is measured by projecting the slit light beam onto the cornea, accurate measurement may not be possible due to the movement of the eye to be measured during measurement. In addition, there is a problem that the configuration is complicated and analysis takes time.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an optometric apparatus capable of accurately and easily measuring a corneal shape regardless of the movement of an eye to be examined.

It is another object of the present invention to provide an optometry apparatus which has a simplified configuration by using a light source for fundus measurement and alignment detection.

[0006]

According to the present invention, there is provided an optometry apparatus for detecting the position of an eye to be inspected, which projects a slit light beam on a cornea while scanning the cornea, and the projection direction is different from the projection direction. A cornea measuring means for imaging and recording a corneal scattered image of the slit light beam from the direction to measure a corneal shape including the periphery of the cornea, and when the corneal scattered image is sequentially recorded, the position detecting means The position is simultaneously detected, and the corneal shape is measured using the detection information obtained by the position detecting means.

The optometry apparatus according to the present invention further comprises a position detecting means for detecting the position of the eye to be inspected, and a corneal scattered image of the slit light beam projected from a direction different from the projection direction by projecting the slit light beam while scanning the cornea. A corneal measuring means for recording and measuring a corneal shape including a periphery of the cornea, and a driving means for driving an optical system of the corneal measuring means, and the corneal scattering image is driven at a plurality of distances by driving the driving means. The corneal shape is measured by imaging and recording.

Further, the optometry apparatus according to the present invention projects the slit light beam onto the cornea while scanning it, captures and records a corneal scattered image of the slit light beam from a direction different from the projection direction, and measures the corneal shape including the periphery of the cornea. The slit luminous flux is moved in parallel and scanned.

An optometry apparatus according to the present invention is an optometry apparatus for measuring a corneal shape from an image obtained by capturing a corneal reflection image of a light source with a video camera. The measurement is performed by

An optometric apparatus according to the present invention detects a corneal reflection image formed by projecting a light beam from a light source onto the fundus of an eye to be examined to detect and measure a fundus reflection image, and aligns the corneal reflection image with the light beam from the light source. The light source is turned on when measuring the light source with a larger light amount than when detecting the position.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a configuration diagram of the optometry apparatus according to the embodiment, and the optical system is shown in a plan view. This apparatus can measure the refraction of the eye, the curvature of the central cornea, and the shape including the periphery of the cornea. An optical path O1 in front of the subject's eye E is a fixation target optical system. On the optical path O1, a dichroic mirror 1, a lens 2, which reflects wavelength light of an infrared LED light source 15 described later, an infrared LED light source 23 described later, and A dichroic mirror 3, a diopter variable lens 4, and a fixation target 5 that reflect the wavelength light of the visible semiconductor laser light source are sequentially arranged. An optical path O2 in the reflection direction of the dichroic mirror 3 is an anterior segment imaging optical path, and includes a mirror 6, a telecentric aperture 7, a lens 8, and a video camera 9 provided at the focal position of the lens 2.

An optical path O3 in the reflection direction of the dichroic mirror 1 is a refraction measuring optical path, and includes a lens 10, a mirror 11,
Perforated mirror 12, central aperture stop 13, conjugate with anterior segment,
The lens 14 and the infrared LED light source 15 are sequentially arranged. In the refraction measurement light receiving optical path in the reflection direction of the perforated mirror 12, a ring stop 16, a light deflecting member 17,
A lens 18 and an array sensor 19 are arranged. A lens 20 and a mirror 21 are disposed on both sides of the optical path O3 in the reflection direction of the mirror 11, and the array sensor 19
Has been reached.

A ring-shaped substrate 22 is provided around the optical path O1.
Are arranged on the substrate 22, and eight infrared LEs for measuring the central part of the cornea and for illuminating the anterior ocular segment having different wavelengths from the light source 15 are provided on the substrate 22.
A D light source 23 is attached. The output of the video camera 9 is connected to a calculation unit 24 including a frame memory and a display monitor 25, and the output of the array sensor 19 is connected to the display monitor 25 via the calculation unit 24.

FIG. 2 is a plan view of a slit light beam projection optical system for measuring a corneal shape, and FIG. 3 is a front view. Optical path O4L, O
4R is in the same plane as the optical paths O1, O2, O3,
Reference numeral 5 is parallel to and above the optical path O1. On the optical paths O4L and O4R in the left and right oblique directions with respect to the eye E,
Lenses 26L, 26R, mirrors 27L, 27R, respectively
A scanning double-sided mirror 30 that is attached to the rotating shaft 29 of the stepping motor 28 and rotates and is arranged at the intersection of the optical paths obliquely upward from the left and right directions of the reflection directions of the mirrors 27L and 27R.

A lens 31, a slit stop 32 extending in a direction perpendicular to the paper, and a cylindrical lens 3 having a generatrix perpendicular to the paper are provided on the optical path O5 in the reflection direction of the scanning double-sided mirror 30.
3. A slit stop 34, a condenser lens 35, and a visible semiconductor laser light source 36 are sequentially arranged.

In such a configuration, the fixation target 5 includes a diopter variable lens 4, a dichroic mirror 3, a lens 2,
It is presented to the eye E through the dichroic mirror 1. At the time of alignment before the measurement, the light source 15 is weakly lit,
This light flux passes through the lens 14 in the optical path O3, the central aperture stop 13,
The light passes through the opening of the perforated mirror 12, the mirror 11, and the lens 10, is reflected by the dichroic mirror 1, and is projected on the cornea C of the eye E to be examined. The corneal reflection image is reflected by the dichroic mirror 1, passes through the outside of the lens 10, and is reflected by the mirror 11, and the lenses 20 on both sides of the refraction measurement optical path O3.
Then, through the mirror 21, two separated corneal reflection images T are formed on the array sensor 19 as shown in FIG. When the positions match, the two-point images T come to the center of the array sensor 19 and are arranged side by side. The alignment can be known from the position of the two-point images T on the screen, and the distance can be detected from the vertically separated state.

At the time of positioning, the light source 23 having a wavelength different from that of the light source 15 is turned on to project a light beam onto the eye E to be examined. The image reflected by this light beam is a dichroic mirror 1, a lens 2
Is reflected by the dichroic mirror 3 and the mirror 6, forms an image on the video camera 9 via the telecentric aperture 7 and the lens 8, and together with the anterior ocular segment image E ′, the corneal reflection image 2
3 'is displayed on the display monitor 25. The examiner adjusts the position by looking at the monitor image.

At the time of corneal curvature measurement, the light source 23 is turned on instantaneously with a larger light quantity than at the time of alignment observation. At this time, in order to prevent the image of the corneal reflection image 23 'from being saturated, the light source 23 is turned off for the remaining time of the frame accumulation time. As in the case of the alignment, the video signals of the eight corneal reflection images 23 'formed on the video camera 9 through the optical path O2 are taken into the calculating means 24, and each position of the corneal reflection image 23' is calculated. The corneal curvature radius in the main meridian direction is calculated. Since the lighting time with a large amount of light is about several tenths to one tenth of one frame, accurate measurement can be performed without being affected by the eye movement of the subject.

Further, the light source 23 does not pass through the diffusion member.
Because of the direct illumination, it is easy to increase the light intensity. When the measurement image is captured from the video camera 9, the signal of the array sensor 19 is
The position of the two-point image T as shown in FIG. 4 is calculated, the distance is detected and corrected, and accurate corneal curvature measurement is performed.

When performing refraction measurement subsequent to corneal curvature measurement, the light source 15 is turned on with a larger amount of light than at the time of alignment. The luminous flux from the light source 15 passes through the optical path O3 in the same manner as in the alignment, and is projected on the fundus of the eye E to be examined. The light reflected from the fundus is reflected by the dichroic mirror 1 and the lens 1
0, the light is reflected at the periphery of the perforated mirror 12 through the mirror 11, passes through the ring stop 16, the light deflecting member 17, and the lens 18, and is transmitted to the array sensor 19 as shown in FIG.
As an image. This shape is calculated by the calculating means 24 to obtain a refraction value including astigmatism. In this case, since the infrared light is used, even if the refraction measurement is performed subsequent to the corneal measurement, there is no influence due to the movement of the eye E to be examined.

When measuring the corneal shape including the peripheral portion, a slit light beam projection optical system is used. The luminous flux of the visible semiconductor laser light source 36 is in a plane parallel to the paper surface.
An image is formed on the slit stop 32 by the cylindrical lens 33 through the condenser lens 35 and the slit stop 34, reflected by the scanning double-sided mirror 30 through the lens 31 to the left or right, and further reflected by the mirror 27 L or 27 R. An image is formed on the cornea C of the eye E by 26L or 26R.

On the other hand, in a plane perpendicular to the plane of the drawing, the visible semiconductor laser
4, the image is formed on the scanning double-sided mirror 30 by the lens 31 and becomes divergent light, reflected by the mirror 27L or 27R, becomes parallel light by the lens 26L or 26R, and further becomes slit light perpendicular to the paper surface to the cornea C. Projected.

Here, the scanning double-sided mirror 30 rotates 90 degrees when the left and right light beams are switched, and scans the cornea C surface while the stepping motor 28 rotates one step at a time during scanning. Also in this case, after the infrared LED light source 23 is turned on to perform positioning, the infrared LED light source 23 is turned off at the time of measurement.

The reflected light from the eye E to be inspected by the visible semiconductor laser light source 36 forms an image on a video camera and is displayed on the display monitor 2.
A corneal scattered image C ′, a lens scattered image S ′, and an iris reflection image K ′ due to slit light as shown in FIG. These images are taken into the calculating means 24 at each rotation step of the scanning double-sided mirror 30, and the surface shape and thickness of each part of the cornea including the peripheral part of the cornea are analyzed from the corneal scattered image C '. At this time, the infrared LED light source 15 is turned on weakly,
The corneal reflection image T of the array sensor 19 shown in FIG. 4 is also captured, and the position of the eye E is recorded for each scattered image C ′.
By calculating this, the position of the eye E at the time of capturing each scattered image C ′ is detected, and each portion is recognized as a scattered image of the cornea C, and accurate shape measurement is performed.

In this manner, accurate shape measurement can be performed even if the eye E moves during scanning. In addition, since the cornea C has a large scattering in visible light, the scattered image C ′
It is preferable to use a visible semiconductor laser light source as a light source for obtaining the laser beam.

The optical system shown in FIGS. 1 to 3 is connected to driving means such as a motor (not shown) for driving at least in the direction of the optical path O1, that is, in the distance direction, and the distance can be detected by the corneal reflection image T in FIG. The driving means is driven so as to perform the distance adjustment based on this.

When the cornea is measured by the slit light beam, a position P1 close to the center of the cornea C as shown in FIG. 7 is driven so as to be conjugate to the imaging surface of the video camera 9, and the scanning double-sided mirror 30 at that position. Scan and capture video. Further, by slightly changing the distance, a position P close to the periphery of the cornea is obtained.
2, the image is captured by scanning again at that position. In the image at the position P1, the central portion of the cornea is clearly seen, and at the position P2, the peripheral portion is clearly seen.

When analyzing the central part of the cornea based on the scattered image C 'shown in FIG. 6, the image taken at the position P1 is used, and when analyzing the peripheral part of the cornea, the image captured at the position P2 is used. In this manner, an accurate analysis can be performed using the unfocused corneal scattered image C ′ within the depth of focus.

Instead of the driving means for moving the entire optical system back and forth, a driving means for moving only the lens 8 along the optical path O2 is provided so that the imaging plane is conjugated to the positions P1 and P2 when measuring the corneal shape. You may make it move.

Further, since the scanning double-sided mirror 30 is disposed at the focal position of the lenses 26L and 26R, the slit light beam can scan the cornea C while moving in parallel.
This facilitates shape analysis. Further, since the size of the image does not change even if the distance is changed by the action of the telecentric stop 7, the shape analysis is further facilitated by combining with the telecentric stop 7.

[0031]

As described above, the optometry apparatus according to the present invention sequentially detects the position of the eye to be examined when measuring the corneal shape by projecting the slit light beam onto the cornea, thereby enabling the eye movement during the measurement. Regardless, accurate measurement can be performed.

The optometry apparatus according to the present invention can improve the measurement accuracy by detecting at a plurality of distances when measuring the corneal shape by projecting the slit light beam onto the cornea.

The optometry apparatus according to the present invention can easily perform an analysis by projecting a slit light beam onto the cornea and scanning the slit light beam while moving the slit light beam in parallel when measuring the corneal shape.

The optometry apparatus according to the present invention can accurately measure the corneal curvature irrespective of the eye movement by turning on the light source while instantaneously increasing the amount of light.

The configuration of the optometry apparatus according to the present invention can be simplified by using the measurement light source for detecting the position of the subject's eye when measuring the fundus.

[Brief description of the drawings]

FIG. 1 is a plan view of an optometry apparatus according to an embodiment.

FIG. 2 is a plan view of a slit projection optical system.

FIG. 3 is a front view of a slit projection optical system.

FIG. 4 is a front view of an array sensor provided with a position detection corneal reflection image.

FIG. 5 is a front view of an array sensor provided with a ring image during refraction measurement.

FIG. 6 is a front view of a display monitor displaying a slit light beam scattering corneal image.

FIG. 7 is a sectional view of an anterior segment.

[Explanation of symbols]

 1, 3 dichroic mirror 5 fixation target 7 telecentric stop 9 video camera 13 center aperture stop 15, 23 infrared LED light source 16 ring stop 17 light deflecting member 19 array sensor 22 ring-shaped substrate 24 operation means 25 display monitor 28 step motor 30 Double-sided scanning mirror 32, 34 Slit stop 36 Visible semiconductor laser light source

Claims (6)

[Claims] 1. A position detecting means for detecting a position of an eye to be inspected, and a cornea including a periphery of the cornea by projecting a slit light beam on a cornea while scanning the cornea and capturing and recording a corneal scattered image of the slit light beam from a direction different from the projection direction. Having a cornea measuring means for measuring the shape, simultaneously detecting the position of the eye to be inspected by the position detecting means when sequentially recording the corneal scattered image, using the detection information obtained by the position detecting means An optometry apparatus for measuring a corneal shape by means of an eye. 2. A cornea including a periphery of a cornea including a position detecting means for detecting a position of an eye to be inspected, a slit light beam projected onto a cornea while scanning the cornea, and a corneal scattered image of the slit light beam captured and recorded from a direction different from the projection direction. A corneal measuring means for measuring a shape, and a driving means for driving an optical system of the corneal measuring means, and the corneal scattering image is recorded at a plurality of distances by driving the driving means to measure the corneal shape An optometric apparatus, comprising: 3. An optometry apparatus that projects a slit light beam onto a cornea while scanning the cornea, and records and records a corneal scattered image of the slit light beam from a direction different from the projection direction to measure a corneal shape including the periphery of the cornea. An optometry apparatus, which scans while moving in parallel. 4. The optometry apparatus according to claim 3, wherein the slit light beam is scanned at a focal position of a slit projection lens while changing an angle of a mirror. 5. An optometric apparatus for measuring a corneal shape from an image obtained by capturing a corneal reflection image of a light source with a video camera, wherein the measurement is performed using an image in which the light source is instantaneously increased in light amount and turned on. An optometric device. 6. A measuring means for projecting a light beam of a light source onto a fundus of an eye to be inspected to detect and measure a fundus reflection image, and a detecting means for detecting and aligning a corneal reflection image by the light beam of the light source. An optometric apparatus characterized in that the light source is turned on when measuring the light source with a larger amount of light than when detecting the position.