JPH04285527A - Ophthalmologic device - Google Patents

Abstract

PURPOSE:To provide an ophthalmologic device by which the state of eyelashes of an eye to be examined can be easily observed when the fore-eye part of the eye is to be observed, and by which whether or not the eye to be examined is in a favorable condition can be simply judged when a prescribed position of the examining eye is to be photographed or measured. CONSTITUTION:The image of the fore-eye part and that of the eyelashes part are simultaneously or sequentially displayed on a TV monitor 19 as the same observing display surface. For instance, the difference in the lengths of the light path between in the case a parallel plane plate 20 lies in the light path and in the case it does not lie in the light path is utilized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmological apparatus that performs alignment of the apparatus by observing an image of the anterior segment of an eye to be examined.

0002

2. Description of the Related Art FIG. 8 is an example of a conventional example of this type of device, and is a schematic diagram of an alignment device for an autorefractometer. An alignment light beam consisting of infrared light emitted from an infrared light emitting diode 22 turned on by a power source 21 passes through an aperture 23, a lens 24, a dichroic mirror 25, and an objective lens 26 to reach the cornea E of the eye E to be examined.
It is projected as parallel light onto c. This light flux is reflected by the cornea Ec, passes through the objective lens 26 again, is reflected by the half mirror 27, is imaged by the television camera 28 together with the anterior segment image including the pupil of the eye E, and is displayed on the television monitor 29. . Further, the optical path passing through the half mirror 27 and the dichroic mirror 25 and heading in the A direction is used for measurement with an autorefractometer or the like.

FIG. 9 shows an image displayed on a television monitor 29, which shows a circle C showing the alignment tolerance projected by another method, an alignment light flux image M by the infrared light emitting diode 22, and a pupil Ep. Statue E
The anterior segment image E' of the subject's eye including p' can be observed two-dimensionally. Then, alignment is performed so that they match.

The images Eh' and El' of the eyelashes Eh and eyelids El (FIG. 10) are blurred on the television monitor 29.

[0005]

[Problems to be Solved by the Invention] Now, as an ophthalmological device, alignment is performed as in the above-mentioned autorefractometer, but for example, a non-contact tonometer requires very strict alignment, and alignment in the optical axis direction is required. In order to accurately perform this, the angle ω (corresponding to the NA of the optical system for anterior segment observation)
Figure 10) needs to be made large. Then, if the position in the optical axis direction is adjusted correctly as shown in Figure 9, the eyelash Eh will be completely blurred and the eyelash Eh will be within the range of the angle ω.
Even if h is applied, the situation cannot be judged from the TV monitor 29. In other words, in FIG. 10, when the observation system has a large angle ω and the observation system is focused on the pupil Ep of the subject's eye, the TV will be visible up to the eyelid El in the vicinity.
I can tell that it's there on the monitor, but I can't really see the eyelashes Eh that protrude in front of my eyes. However, in a non-contact tonometer, airflow is blown onto the cornea Ec and its deformation is optically detected, so the influence of the eyelashes Eh is significant, and sometimes the measured value is 2 to 3 mm.
Hg was also sometimes displayed high. Therefore, there is a demand for monitoring the state of the eyelashes Eh in a state where alignment is performed before measurement. Note that this applies not only to non-contact tonometers but also to other ophthalmological apparatuses including autorefractometers and fundus cameras.

[0006] An object of the present invention is to provide an ophthalmological apparatus that can clearly monitor the state of the eyelashes of the eye to be examined.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an observation means for monitoring the anterior segment image of the subject's eye;
In an ophthalmological apparatus that has a photographing or measuring means for photographing or measuring a predetermined part of the eye to be examined, and performs the photographing or measuring by aligning the eye to be examined and the apparatus by the observation means, the eye to be examined is within the observation field of the observation means. It is characterized by having an image forming means for forming an image of the eyelash portion.

[0008]

[Operation] For example, a clear image of the eyelashes is formed on the TV monitor 19, which forms an image of the anterior segment of the subject's eye, by utilizing the difference in optical path length when the parallel plane plate 20 is present and when it is not.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a non-contact tonometer according to an embodiment of the present invention. The airflow spraying device drives a piston 1 using a solenoid to compress air in a cylinder 2, and sprays an airflow from a nozzle 3 onto the cornea Ec of the eye E to be examined, so as to give a certain deformation to the cornea Ec. It has become. Since intraocular pressure is related to this deformation, intraocular pressure can be determined by the pressure that causes a certain amount of deformation. It is necessary to open a window in the cylinder 2 in the part that corresponds to the optical path of the optical system that detects the deformation of the cornea Ec, and this window part has a flat glass,
Light transmitting members 4 and 5 made of lenses and the like are provided, and the nozzle 3 is attached to the center of the light transmitting member 4 facing the eye E to be examined. Furthermore, in order to optically detect the deformation of the cornea Ec, a projection optical system that projects a light beam onto the cornea Ec and a light receiving optical system that receives the corneal reflection are provided. The projection optical system includes a lens 6 provided behind the light transmitting members 4 and 5;
It consists of a light splitting member 7 and a lens 8 provided on the reflective side of the light splitting member 7, for example an infrared light source 9, and the infrared light beam from the light source 9 is divided into the lens 8, the light splitting member 7, the lens 6, and the light beam. The light is projected onto the cornea Ec through the transmission member 5 and the nozzle 3. Further, the corneal reflected light passes through the light transmitting members 4 and 5, the lens 6, and the light splitting member 7a, is reflected by the light splitting member 7b, passes through the lens 10, and is received by the light receiving element 11.

When the piston 1 inside the cylinder 2 moves,
The pressure on the cornea Ec increases with time t, as shown in FIG. Then, at a certain point, the cornea Ec deforms so that its curvature becomes gentler. If the light-receiving element 11 is installed in advance so that the light beam is focused on the light-receiving element 11 when the cornea Ec reaches a predetermined curvature, the intraocular pressure can be determined from the pressure when the amount of light reaches its maximum. .

FIGS. 2 to 5 show the relationship between the amount of light 1 incident on the light receiving element 11 and the time t. In a normal case, the signal based on the amount of light has a peak shape at time to, as shown in FIG. However, the signals measured when the eyelids and eyelashes of the subject's eye E have drooped, or when tears have accumulated in the cornea Ec, are deformed as shown in FIGS. 4 and 5, respectively. For example, when the eyelids and eyelashes lower and come close to the airflow, the resistance causes turbulence, which causes the signal to become multimodal and mountain-shaped as shown in Figure 4, reducing the accuracy of the measured values. . Furthermore, when tears accumulate in the cornea Ec, the curved surface of the cornea Ec becomes uneven, so that the mountain-shaped peak of the signal becomes rounded, as shown in FIG. 5, and the accuracy of the measured value decreases in this case as well.

The output of the light receiving element 11 is transmitted to a peak detection circuit 12.
are input in parallel to the A/D converter 13.
3 sends its output to the controller 16, which uses it to calculate the reliability of the measurement.

On the other hand, the peak signal from the peak detection circuit 12 is used as a timing pulse for the A/D converter 15, and the pressure inside the cylinder 2 is read as a signal from the pressure sensor 14. The controller 16 converts it into intraocular pressure. Convert and display.

On the other hand, regarding alignment, the infrared light source 9
The corneal reflection image and the image of the pupil Ep of the subject's eye are the lenses 6 and 1.
7 on the CCD camera 18, and by combining these. The anterior segment image captured by the CCD camera 18 is depicted on the TD monitor 19. The parallel plane plate 20 provided between the lens 17 and the CCD camera 18 in FIG. 1 is used to set the focal position in the eye space to be examined to be different depending on different parts on the screen of the CCD camera 18. The thickness is determined so that when the device is properly aligned, the portion through which the plane parallel plate 20 is passed is conjugate with the pupil of the eye to be examined, and the portion where it is not is conjugate with the vicinity of the eyelashes of the eye to be examined. That is, the same CCD camera 18
In this method, images at different positions in the optical axis direction by d (distance between the pupil Ep and the eyelash Eh of the subject's eye) are simultaneously projected in good focus in the first region through which the parallel plane plate 20 is passed and the second region through which the parallel plane plate 20 is not passed. It is possible.

The image E' of the eye to be examined thus depicted on the TV monitor is as shown in FIG. The corneal reflection image M of No. 9 is in focus, and the eyelash image Eh' is in focus in the second area Eb' which does not pass through the parallel plane plate 20.

In the embodiment described above, the CCD camera 18
By providing a parallel plane plate 20 immediately in front of the screen, screen division and focus position setting are performed simultaneously. For this reason, the image is slightly distorted at the boundary between the areas Ea' and Eb' in FIG. 6, but in order to avoid this, a good method is to relay the anterior segment image once and then divide the screen at the conjugate plane.

For example, in FIG. 7, a small mirror Mo is provided at the position where the anterior eye segment image is formed by the lens 6a, and the anterior eye segment image including the pupil of the subject's eye is reflected by the small mirror Mo and sent to the CCD by the lens 17a.
While the image of the eyelash area is re-imaged on lens 18a, the image of the eyelash area is
Once imaged by a, the lens 1 passes through the periphery of the small mirror Mo.
7b, the image is re-imaged onto the CCD 18b and displayed on the TV monitor 19.
Display simultaneously or sequentially.

In the embodiment shown in FIG. 1, the plane-parallel plate 20 is sized to cover the entire surface (area Ea' and Eb'), and the plane-parallel plate 20 is movable perpendicular to the optical axis, so that the eyelash image can be clearly observed. If desired, it may be moved to a position covering only area Ea' as shown in FIG. 1, and when normal anterior segment observation is performed, it may be returned to a reference position covering the entire surface (area Ea' and area Eb'). good.

In the non-contact tonometer described above, not only the reliability of the measured value can be determined from the measurement signal, but also the influence of eyelashes can be observed on a TV monitor before measurement. This eliminates the risk of making unnecessary measurements or making incorrect diagnoses due to unreliable measurements.

Although the non-contact tonometer has been described as an example, the present invention is not limited to this, and since eyelashes are a source of flare in fundus cameras, refractometers, and keratometers, they can be used in various ways including these. The present invention can be similarly applied to other ophthalmological devices.

[0021]

[Effects of the Invention] As described above, according to the present invention, when observing the anterior segment of the eye to be examined, the condition of the eyelashes of the eye to be examined can be easily monitored;
It is possible to easily determine whether or not the eye to be examined is in a suitable state when photographing or measuring a predetermined region of the eye to be examined.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a non-contact tonometer as an embodiment of the present invention.

FIG. 2 is a diagram showing temporal changes in pressure on the cornea as the piston moves.

FIG. 3 is a diagram showing temporal changes in the amount of light from a light receiving element as the piston moves.

FIG. 4 is a diagram showing temporal changes in the amount of light from a light receiving element as the piston moves when the eyelids and eyelashes are lowered.

FIG. 5 is a diagram showing temporal changes in the amount of light of the light receiving element as the piston moves when tears accumulate on the cornea.

FIG. 6 is a diagram showing an image of the subject's eye on a TV monitor as an observation display screen.

FIG. 7 is a diagram of different embodiments of the invention.

FIG. 8 is a diagram showing a conventional refractometer alignment device.

FIG. 9 is a diagram showing an observed image of the anterior segment of the eye using a conventional ophthalmological device.

FIG. 10 is a diagram showing the influence of eyelashes on the eye to be examined.

[Explanation of symbols]

E Tested eye Ec Cornea of the eye to be examined Ep Tested eye pupil El eyelid of eye to be examined Eh Eyelashes of the eye to be examined 6 Objective lens 7 Lens 18 CCD camera 19 TV monitor 20 Parallel plane plate

Claims (1)

[Claims] 1. A method comprising an observation means for observing an image of the anterior segment of the eye to be examined, and a photographing or measuring means for photographing or measuring a predetermined part of the eye to be examined, and the observation means aligns the eye to be examined and the device to take the image. Alternatively, an ophthalmological apparatus for performing measurement, comprising an image forming means for forming an image of the eyelash portion of the eye to be examined within the observation field of the observation means.