JPS6397141A - Tonometer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention deforms the cornea by blowing air onto the eye to be examined.
The present invention relates to a so-called non-contact tonometer that determines the intraocular pressure of the eye to be examined from its deformation.

[Prior Art] Conventionally, in this type of intraocular pressure 31, the finder is usually composed of an optical system, and the examiner observes an aerial image. On the other hand, in such a tonometer, since an air stream is blown onto the eye to be examined, the eyelashes of the eye to be examined may fall on the area of the air blown, and in this case, an error will occur in the measurement. However, when looking at an aerial image through a viewfinder, the diopter of the examiner's eye moves due to accommodation, so it is difficult to see how well the eyelashes are applied, and even if there is an influence from the eyelashes, it is difficult to tell. I will continue to take measurements.

[Object of the Invention] The object of the present invention is to eliminate the error caused by the eyelashes by making it possible to clearly see how well the eyelashes are applied when performing observation positioning using a finder, in order to overcome the problems mentioned above. Our objective is to provide a tonometer.

[Summary of the Invention] The gist of the present invention to achieve the above-mentioned object is to provide an eye for measuring intraocular pressure from deformation of the cornea by blowing air onto the cornea of the eye to be examined from an air compression chamber having a light-transmitting part through a nozzle. The tonometer is characterized in that the tonometer is equipped with an image capturing means for capturing an image of the anterior segment of the eye to be examined through the light transmitting section.

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

FIG. 1 shows an embodiment of a tonometer according to the present invention, in which air in an air compression chamber 1 is compressed by a piston 3 driven by a Truid 2, and a nozzle 4 is also used to spray the cornea Ec of the eye E. It has become. The air compression chamber 1 is provided with a light transmitting section consisting of a light transmitting member 5, 6 such as a flat glass or a lens, and behind the light transmitting member 6 are a lens 7, a light dividing member 8, and an aperture for imaging the anterior segment of the eye. 9, a light splitting member 10, a lens 11, and an imaging member 12 such as an imaging tube are arranged in this order. A measurement lens 13 and a light source 14 are provided on the reflective side of the light splitting member 8, and a lens 15 is provided on the reflective side of the light splitting member 10.
, photoelectric elements 16 are arranged respectively. Further, a light source 1 having a wavelength different from that of the light source 14 is provided around the light transmitting member 5.
7 is arranged, and the output of the imaging member 12 is connected to a monitor 18.

The light emitted from the light source 14 is projected onto the cornea Ec via the lens 13 and the light splitting member 8, and the reflected light is reflected by the light splitting member 1.
0, the light is received by the photoelectric element 16 through the lens 15. This reflected light reaches a maximum when the cornea Ec undergoes a predetermined deformation due to the air flow, and the intraocular pressure is determined from the pressure at this time.

An image of the anterior segment of the eye E to be examined is formed on the imaging member 12 by an optical system including the lens 7, the lens 11, etc., and the image can be observed on the monitor 18.

The light source 14 also serves as a light source for determining the working distance, and when determining the working distance, light from the light source 14 is projected onto the cornea Ec through the nozzle 4. The reflected light from the cornea passes around the nozzle 4 and forms a corneal reflected image 14a on the imaging member 12, but when looking at the monitor 18, the corneal reflected image 14a is
The point where the lens is in focus is the point with the best working distance. Since this imaging light beam is large and has a shallow depth of focus, the working distance can be adjusted with high precision.

In the embodiment, the wavelength of the light source 17 near the periphery of the light-transmitting member 5.6 is different from that of the light source 14. Aperture 9 for anterior segment imaging
As illustrated in FIG. 2, the central portion 9a also transmits the wavelength of the light source 17, but the peripheral portion 9b is configured not to transmit this wavelength, and the depth is increased by the anterior segment imaging aperture 9. As a result, the eyelashes of the eye E to be examined can be seen better. That is, the corneal reflection image 14a is formed near the iris of the eye E to be examined, but since the eyelashes are located further forward, the deeper the image, the easier it is to see.

It is preferable that both the light sources 14 and 17 are near-infrared light sources, and that the imaging member 12 is a near-infrared imaging tube. This is because the iris reflects near-infrared light to a large extent, so when near-infrared light is used, the iris appears white, and the eyelashes look even better against the background.

When aligning the observation position in this way, the air blower allows you to clearly see how the eyelashes overlap with the area, so if the eyelashes seem to be affecting the area, take appropriate measures such as instructing the patient to raise the eyelids further. This allows accurate measurements to be taken under the most appropriate conditions.

In the above embodiment, the measurement light is projected from the air flow direction,
Although it receives light, it may also project and receive light from an oblique direction like a conventional general tonometer. In that case, it is preferable to separately provide a light source on the optical axis for determining the working distance.

[Effects of the Invention] As explained above, the tonometer according to the present invention allows the image of the anterior segment of the subject's eye to be observed on a fixed surface such as an imaging member. The condition of the eyelashes can be clearly understood from the degree of blur in the eyelash image, and it is possible to know the influence of the eyelashes on the measurement. In addition, when near-infrared light is used, the iris appears white and the eyelashes are clearly reflected against the background, making it possible to better observe the condition of the eyelashes.Furthermore, the condition of the eyelashes can be further monitored using the anterior segment imaging aperture. This allows for even better observation.

[Brief explanation of the drawing]

The drawings show an embodiment of the intraocular pressure sensor according to the present invention, and FIG. 1 is a configuration diagram thereof, and FIG. 2 is a front view of an diaphragm for imaging the anterior segment of the eye. 1 is an air compression chamber, 4 is a nozzle, 5.6 is a light transmitting member, 8.10 is a light dividing member, 9 is an anterior segment imaging aperture, 12
is an imaging member, 14.17 is a light source, 16 is a photoelectric element, 18
is a monitor.

Claims (1)

[Scope of Claims] 1. In a tonometer that measures intraocular pressure from the deformation of the cornea by blowing air from an air compression chamber having a light-transmitting part through a nozzle onto the cornea of the subject's eye, the anterior eye of the subject's eye is sprayed through the light-transmitting part. A tonometer characterized by comprising an imaging means for taking an image of the area. 2. The tonometer according to claim 1, wherein the imaging means uses near-infrared light. 3. The tonometer according to claim 1, wherein the light source for illuminating the anterior ocular segment used in the imaging means uses a light source having a wavelength different from that of the light source used for adjusting the working distance.