JP2000254099A - Ophthalmologic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic device capable of performing a check in natural feeling without applying a load to a subject and, after a blink, capable of detecting the generation of a lacrimal membrane damage phenomenon caused by drying of lacrimal fluid to perform an accurate check. SOLUTION: The point of time when a signal waveform of a corneal reflecting image reappears by eye opening after a corneal reflecting image of a pattern is temporarily disappears by eye opening at a blink is used as a starting point of BUT time. A time for detecting a fact that the lacrimal membrane damage phenomenon appears with a lapse of time to cause disturbance in a detecting signal waveform of the corneal reflecting image with television scanning lines Sa-Sd is automatically measured by a time measuring means, and the measured time data D is displayed on a television monitor 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus capable of detecting the occurrence of tear film destruction due to tear drying on a corneal surface of an eye to be examined.

[0002]

2. Description of the Related Art Conventionally, in determining the suitability of wearing a contact lens, the BU from the blinking until the tear film destruction phenomenon, in which a tear layer is deficient with the drying of the tear film, appears.
It is extremely important to know the T time (tear film break up time). Furthermore, the causal relationship between eye strain associated with VDT work and BUT time has recently been attracting attention, and its clinical value is increasing.

(1) As a method of measuring the BUT time,
There is known an inspection method in which a fluorescein solution is instilled into an examinee's eye, and a time until a tear film destruction phenomenon appears after a blink is manually measured while observing a corneal surface with a slit lamp.

(2) In addition, in research, the appearance of the tear film destruction phenomenon is captured with the naked eye by projecting a reticulated pattern onto the cornea of the eye to be examined and magnifying and observing the corneal reflection image with an optical finder. Attempts have been made.

(3) Further, recently, a special ophthalmic apparatus has been developed in which the dry state of tears can be observed by an image using an interference optical system.

[0006]

However, the test method of the above-mentioned conventional example (1) has a problem that the original characteristics of tears are changed because fluorescein solution is mixed into tears. .

In the method of the conventional example (2), it is difficult to detect the distortion or disorder of the mesh pattern of the corneal reflection image, which changes with the drying of the tear, by visual observation, and it is difficult for the examiner to observe the distortion. There is a problem that the degree to which the tear film destruction phenomenon is recognized varies depending on the degree of attention and skill.

Furthermore, in the conventional example (3), skill is required to rely on sensory judgments, and since it is a single and special dedicated machine, an installation space is required and it is necessary to move a patient. There is a problem that it takes time.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an ophthalmologic apparatus that automatically detects the occurrence of a tear film destruction phenomenon accompanying the drying of tears after blinking and the elapsed time until the occurrence.

[0010]

According to the present invention, there is provided an ophthalmologic apparatus for projecting a predetermined pattern onto a cornea of an eye to be examined, and a corneal reflection image of the pattern projected from the projection means. Imaging means for imaging the eye, detecting means for detecting the occurrence of a tear film destruction phenomenon due to a change in the state of the corneal reflection pattern image accompanying tear drying from the signal waveform of the imaging means, and opening the eyelid after the subject's eye blinks And a measuring means for measuring an elapsed time until the detecting means detects the occurrence of the tear film destruction phenomenon after the detecting means detects the eyelid opening.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a side view of the device of the first embodiment,
FIG. 2 shows a configuration diagram of the optical system. The head unit 1 in which the optical system is housed is mounted on a slide base unit 2 so as to be able to move up and down like a general ophthalmic apparatus, and is slid in the front-rear and left-right directions on a fixed base 3. I have. Further, a face rest unit 4 for stably holding the face of the subject is fixed to the fixed base 3.

A pattern projection plate 6 having an optical opening 5 at the center as shown in FIG. 3 is attached to the front surface of the head unit 1 facing the eye E to be examined. A stripe pattern in which light transmitting portions and light shielding portions are alternately arranged at substantially equal intervals in a slit shape is drawn. A ring-shaped light source 7 is arranged behind the pattern projection plate 6,
An illumination light source 8 for illuminating the anterior segment of the eye E is arranged near the left and right sides of the pattern projection plate 6.

On the optical path in front of the subject's eye E, a dichroic mirror 9 and an objective lens 1
0, the image sensor of the television camera 11 is arranged. In the reflection direction of the dichroic mirror 9, a dichroic mirror 12 and a fixation target unit 13 for removing the accommodation power of the eye E and fixing the line of sight are arranged. In the reflection direction of the dichroic mirror 12, the eye E A detection unit 14 for detecting an eye refractive power is arranged.
The output of the television camera 11 is connected to the electric circuit unit 15, and the output of the electric circuit unit 15 is connected to a television monitor 16 composed of a liquid crystal display attached to the side of the examiner of the head unit 1.

[0014] The subject's face is fixed by the face application unit 4;
While gazing at the fixation target of the fixation target unit 13, the positioning operation of the slide unit 2 is performed so that the head unit 1 has an appropriate positional relationship with the cornea Ec of the eye E to be examined. At this time, the anterior segment image of the eye E illuminated by the anterior segment illumination light source 8 passes through the optical opening 5, the dichroic mirror 9, and the objective lens 10, is imaged by the television camera 11, and The image is displayed on the monitor 16.

When the ring light source 7 is turned on in this state, the pattern projection plate 6 is illuminated from behind by the ring light source 7 and projected onto the cornea Ec of the eye E to be examined. The corneal reflection image of this pattern is formed on the television camera 11 by the objective lens 10 through the optical opening 5. Then, a change in the state of the corneal reflection image of the pattern projection plate 6 captured by the television camera 11 is detected by the electric circuit unit 15 and displayed on the television monitor 16. The examiner finely adjusts the position so that the corneal reflection image becomes sharpest.

FIG. 4 shows an image on the television monitor 16, and the change in the state of the corneal reflection image of the projection pattern is represented by the television scan line S
Detection is performed at four sites indicated by a to Sd. The corneal surface immediately after the subject's eye E blinks is completely moistened with tears and is in a completely convex mirror state. Therefore, the corneal reflection images of the corneal reflection images of the bright and dark patterns at the respective detection sites are displayed on the television scanning lines Sa to Sd. As shown in FIGS. 5A to 5D, the signal waveforms are uniform in height and interval.

As time elapses from this state, the tears gradually evaporate, and tear film destruction occurs from near the lower central region of the cornea Ec. Since the corneal surface of the dry spot, which is the site where the tear film destruction phenomenon has occurred, is no longer in a mirror state, a phenomenon in which the brightness of the corneal reflection image of the light and dark pattern is partially reduced or disturbed appears. At this time, the signal waveforms of the television scanning lines Sa to Sd at the respective detection sites have irregular heights or intervals as shown in FIGS. 6 (c) and 6 (d).

BU from blinking to tear film destruction
To measure the T time, the point at which the signal waveform of the corneal reflection image appears again by the opening of the eyelid after the corneal reflection image of the pattern once disappears due to the eyelid closing at the time of blinking is set as the measurement start point of the BUT time. The time until the detection signal waveform of the corneal reflection image is detected by the occurrence of the tear film destruction phenomenon with the passage of time and the detection signal waveform is disturbed is automatically measured by the timer, and the measured time data D is displayed on the television monitor 16, Printing is performed on a printer (not shown). Then, such measurement is performed a plurality of times to check the variation or calculate the average value.

Here, as a method for detecting the disturbance of the detected waveform signal, the height Sh of the signal waveform immediately after blinking and opening of the eyelid or after a relatively short time has passed is stored, and then the tear is read. When the signal waveform becomes the height Sh 'due to the drying of the liquid, for example, a portion where Sh' / Sh becomes 1/3 or less appears, or a phenomenon that the interval between the signal waveforms becomes wide or fluctuates. By detecting the appearance time point, it is determined that tear film destruction has occurred due to drying of the tear fluid on the corneal surface.

In this manner, the test can be performed with a natural feeling without putting a burden on the subject without instilling the fluorescein solution or the like into the subject's eye, and without depending on the skill of the examiner. After blinking, the occurrence of tear film destruction due to the drying of tears is automatically detected, and the dry state of the cornea Ec can be known. By accurately measuring the BUT time, it is possible to accurately determine whether or not the test is appropriate. It can be carried out. Furthermore, a simple structure in which the pattern projection plate 6 and the ring-shaped light source 7 are added while partially sharing the constituent members including the anterior ocular segment imaging means for measuring the eye refractive power, the corneal shape, etc. The BUT time detection function can be combined at a low cost. By such a combination, a space for installing a dedicated device can be saved, and it is not necessary to move a subject, and an examination can be performed in a short time.

FIG. 7 is a block diagram of the second embodiment, in which pattern projection is performed only on the area below the pupil of the cornea Ec. An objective lens 20 is arranged in front of the subject's eye E, a projection pattern plate 21 is provided below the objective lens 20, and a light source unit 22 including a light emitting diode array is arranged behind the projection pattern plate 21. Other components are the same as those of the first embodiment, and the same reference numerals as those in FIG. 1 denote the same members.

The projection pattern plate 21 is, as shown in FIG.
It is formed in a small rectangular shape in which light transmitting portions and light transmitting portions are alternately arranged in a slit pattern. The location S where the corneal reflection image of the pattern is detected is also 1 as shown in FIG.
Only in the places. If the light source unit 22 is a red light emitting diode and the anterior ocular segment illumination light source 8 is turned off or dimmed during pattern projection, the contrast between the iris portion and the corneal reflection image of the pattern can be improved.

In this manner, the projection pattern plate 21 and the light source unit 22 can be incorporated in a small space, and can be put to practical use at low cost. Since it starts from the lower pupil region of Ec, it can be a clinically effective device.

FIG. 10 is a block diagram of the third embodiment, in which a projection chart of a multiple ring composed of a Placido ring is projected on the cornea Ec of the eye E to be examined, and the apparatus for analyzing the surface shape of the cornea Ec has a BUT time. It is a combination of detection functions.

On the surface of the head unit 1 on the side of the eye E to be examined, as shown in FIG. 11, a projection chart plate 31 composed of multiple rings having an opening 30 in the center is formed, and a ring light source 32 is disposed behind the projection chart plate 31. ing. On the optical path in front of the subject's eye E, a television camera 35 including an opening 30 at the center of the projection chart plate 31, an objective lens 33, a dichroic mirror 34, a CCD, and the like is arranged, and on an optical path in a reflection direction of the dichroic mirror 34. Has a fixation target lens 36,
A fixation lamp 37 is provided.

The multi-ring projection chart plate 31 is illuminated from behind by a ring-shaped light source 32 and projected onto the cornea Ec of the eye E to be examined. The corneal reflection image is taken by a television camera 35 via an objective lens 33 and a dichroic mirror 34. At this time, the dichroic mirror 34 is
Then, the fixation lamp 37 is gazed through the fixation target lens 36 to fix the movement of the eye.

As described above, the state of the signal waveform of the corneal reflection image in the radial meridian direction as shown in FIG. Disorder of the corneal reflection image due to drying can be automatically detected.

[0028]

As described above, the ophthalmologic apparatus according to the present invention projects a predetermined pattern on the cornea of the subject's eye, captures a corneal reflection image of the pattern, and detects the state of the corneal reflection pattern image. The occurrence of the tear film destruction phenomenon due to tear drying after blinking and the elapsed time until the occurrence can be easily and automatically measured with a simple configuration. As a result, an accurate examination can be performed with a natural feeling without relying on the skill of the examiner and without placing a burden on the subject.

[Brief description of the drawings]

FIG. 1 is a side view of a first embodiment.

FIG. 2 is a configuration diagram.

FIG. 3 is a front view of a pattern projection plate.

FIG. 4 is an explanatory diagram of a display image.

FIG. 5 is a graph of a detection signal waveform.

FIG. 6 is a graph of a detection signal waveform.

FIG. 7 is a configuration diagram of a second embodiment.

FIG. 8 is a front view of the pattern projection plate.

FIG. 9 is an explanatory diagram of a display image.

FIG. 10 is a configuration diagram of a third embodiment.

FIG. 11 is a front view of a projection chart plate.

FIG. 12 is an explanatory diagram of a display image.

[Explanation of symbols]

 6, 21, 31 Projection chart plate 7, 22, 32 Light source for projection chart illumination 8 Light source for anterior segment illumination 10, 20, 33 Objective lens 11, 35 TV camera 13 Fixation target unit 14 Eye refractive power detection unit 16 Television Monitor 37 Fixation light

Claims (5)

[Claims] 1. A projection device for projecting a predetermined pattern onto a cornea of an eye to be examined, an imaging device for capturing a corneal reflection image of the pattern projected from the projection device, and a signal waveform of the imaging device associated with tear drying. Detecting means for detecting the occurrence of tear film destruction by a change in the state of the corneal reflection pattern image; detecting means for detecting that the subject's eye has opened after blinking; and An ophthalmologic apparatus comprising: measuring means for measuring an elapsed time until the detecting means detects occurrence of a tear film destruction phenomenon. 2. A method according to claim 1, wherein the imaging unit is used for capturing an anterior eye image, a corneal reflection image of a pattern projected from the projection unit is captured by the imaging unit, and a change in an imaging signal waveform captured by the imaging unit. The ophthalmologic apparatus according to claim 1, wherein a function of automatically detecting a change in the state of the corneal reflection pattern image due to the tear film destruction phenomenon is combined with the detection means, and an eye refractive power and a corneal shape are examined. 3. The detecting means electrically detects a change in a state of a corneal reflection image associated with drying of a tear in a predetermined pattern projected on a cornea of an eye to be examined in a predetermined range or a plurality of locations of the cornea, and detects the detected change. The ophthalmologic apparatus according to claim 1, wherein the occurrence of the tear film destruction phenomenon is detected based on a signal waveform. 4. A detection signal waveform of the corneal reflection pattern image immediately after a blink or after a predetermined time, and detection when a state of the corneal reflection pattern image changes due to drying of tears on a corneal surface. The ophthalmologic apparatus according to claim 1, wherein the occurrence of the tear film destruction phenomenon is detected by comparing the signal waveform with a signal waveform. 5. The ophthalmologic apparatus according to claim 1, wherein a pattern projected on the cornea of the eye to be detected for detecting occurrence of the tear film destruction phenomenon is shared with a projection pattern for measuring a corneal shape.