JPS6219149A - Fluid pulse emission controller of eye pressure measuring apparatus - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an intraocular pressure measuring device used to measure the internal pressure of the eyeball, and in particular, to an intraocular pressure measuring device that is used to applanate the cornea with a fluid pulse. The present invention relates to a fluid pulse emission control device for a non-contact intraocular pressure measuring device.

[Prior Art] A non-contact intraocular pressure measuring device that uses fluid pulses sprays a fluid pulse onto the corneal surface from the axial direction of the device and measures the intraocular pressure based on the time taken until the cornea is applanated. However, the intraocular pressure is calculated assuming that the corneal apex is aligned with the axis of the device, so if the corneal apex is not aligned with the axis of the device, accurate intraocular pressure measurement is required. It is not possible.

Conventionally, this type of intraocular pressure measuring device projects a aiming light onto the corneal surface from the axial direction of the device, and disposes a light detection means at the convergence position of the aiming light reflected from the corneal surface along the axis. The output signal from the light sensing means controlled the operation of the fluid pulse emitting means such that a fluid pulse was emitted only when the intraocular pressure measuring device was in the correct position.

(Japanese Patent Publication No. 5B-8772) [Problems to be Solved by the Invention] The above-mentioned conventional intraocular pressure measuring device projects a aiming light onto the corneal surface from the axial direction of the device and detects the reflected light. Therefore, when the axis of the device and the corneal vertex coincide, as shown in Figure 2, there are two cases: when the aiming light converges on the 8th surface of the cornea, and when it converges on the center of curvature of the cornea a. In any case, the reflected light of the aiming light is converged on the light detection means C, and in any of the above cases where the distance between the device and the corneal surface is different, a fluid pulse is emitted to measure the intraocular pressure.

However, since the intraocular pressure is calculated on the assumption that the flow velocity of the fluid pulse at the corneal surface is a predetermined velocity, the distance between the device and the corneal surface must be a predetermined constant distance.
Therefore, in the above-mentioned conventional intraocular pressure measuring device, the distance at which the measurement was performed was incorrect, and the measured value was often incorrect.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid pulse ejection control device for an intraocular pressure measuring device that can eliminate such drawbacks and always accurately measure intraocular pressure.

[Means for Solving the Problems] In order to achieve the above object, the fluid pulse emitting control device for the intraocular pressure measuring device of the present invention includes a fluid pulse emitting means that ejects fluid pulses from the axial direction of the device toward the corneal surface. and aiming light projecting means for projecting aiming light onto the coloring film surface obliquely from the side of the axis; and aiming light detection means for receiving the aiming light reflected on the corneal surface on the opposite side of the axis. and the operation of the fluid pulse emitting means is controlled by an output signal from the aiming light detecting means.

[Function] After the aiming light projected from the aiming light projection means is reflected at the corneal vertex, the aiming light is aimed only when the corneal vertex and the axis of the device coincide and the distance between the device and the corneal surface is a predetermined distance. Upon entering the light sensing means, the fluid pulse emitting means becomes ready to emit an air pulse.

[Example] An embodiment of the present invention will be described based on FIG.

1 indicates the axis of the apparatus, and a fluid pulse emitting means 3 is provided for ejecting a fluid pulse from the direction of this axis 1 to two surfaces of the subject's cornea. This fluid pulse emitting means 3 is composed of a solenoid 4, a piston 5, a cylinder 6, and a nozzle 7. When the solenoid 4 is energized, the piston 5 moves within the cylinder 6, and the air within the cylinder 6 is directed toward the object. The liquid is ejected from the nozzle 7 provided at the center of the lens 14 toward the two surfaces of the subject's cornea.

A light emitter 8 and a light receiver 9 are provided so as to form equal angles to the two corneal surfaces, and the amount of light emitted from the light emitter 8, reflected by the two corneal surfaces, and incident on the light receiver 9. is at its maximum when the two surfaces of the cornea are applanated by the air pulse, so the intraocular pressure can be calculated from the time until the amount of light received by the light receiver 9 reaches its maximum.

Reference numeral 10 denotes a light emitting diode that projects an image of a target 10a as a guide for detecting the positional relationship between the axis 1 of the apparatus and the cornea 2 of the subject. is reflected along objective lens 1
4 and projects an image of the target 10a onto two surfaces of the cornea. Then, the reflected image of the target lea by the two corneal surfaces is reflected by the objective lens 1.
4 and beam splitter 13, the image is projected by an imaging lens 16 onto a transparent screen plate 18 disposed on an imaging plane 17, and the examiner can observe this through an eyepiece 19.

Reference numeral 20 denotes an aiming light projecting means for projecting aiming light obliquely onto the two surfaces of the cornea from the side of the axis l. It consists of a convex lens 22 that converges onto a surface.

Reference numeral 23 indicates an aiming light detecting means disposed at a position symmetrical to the aiming light projecting means 20 across the axis l, and this aiming light detecting means 23 is a photoelectric element that receives the aiming light and outputs an electrical signal. 24, and a convex lens 25 that projects an image on the two surfaces of the cornea onto the photoelectric element 24.

And the output signal from the photoelectric element 24 is as follows.

The comparator 26 compares it with the set received light amount signal value 27, and when the deviation value resulting from the comparison becomes less than a certain value, an activation signal is issued from the trigger generator 28.

AND circuit 2 inserted in the power supply circuit to solenoid 4
9 is input. Then, when the AND circuit 29 is turned on while the switch 30 of the power supply circuit is already turned on, the solenoid 4 is energized and an air pulse is emitted.

Next, the operation of this embodiment will be explained. Subject's cornea 2
When the subject is made to stare at the target 10a by aligning it with the axis l of the device, and the position is adjusted using a known adjusting device (not shown) so that the image of the target 10a is on two corneal surfaces, the reflection The image is projected onto the transparent screen plate 18, and the reflected image of the target is observed by the examiner through the eyepiece lens 19. If the apex of the cornea 2 does not coincide with the axis &11, the reflected image of the target will be projected onto the periphery of the transparent screen plate 18 other than the center. The reflected image is brought close to the center of the transparent screen plate 18.

When the two corneal vertices and the axis of the device exactly match and the distance between the device and the cornea is a predetermined distance, the aiming light projected from the aiming light projection means 20 is reflected at the two corneal vertices, and then
As shown by the dotted line in FIG. 1, the aiming light enters the detection means 23, the photoelectric element 24 outputs a received light amount signal, and the trigger generator 2
8 is input to the AND circuit 29, the AND circuit 29 is turned on, the solenoid 4 is energized, and an air pulse is automatically emitted toward the two surfaces of the cornea.

However, if the distance between the device and the cornea is not a predetermined distance, the light beam projected from the aiming light projection means 20 does not enter the aiming light detection means 23 after being reflected on the two surfaces of the cornea.
Therefore, no air pulse is fired.

Incidentally, in the above embodiment, the air pulse is automatically emitted, but by manually turning on the switch 30 while the trigger signal from the trigger generator 28 is being input to the AND circuit 29. Air pulses may also be emitted.

[Effect of the Invention 1] According to the fluid pulse emission control device of the intraocular pressure measurement device of the present invention, only when the corneal apex and the axis of the device coincide and the distance between the device and the cornea is a predetermined correct distance. Since a fluid pulse is emitted to measure intraocular pressure, false intraocular pressure values are not measured, and the intraocular pressure can always be accurately measured.

Furthermore, since a beam splitter is not required for projecting and receiving aiming light, assembly and adjustment of the device is easy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the fluid pulse emission control device of the intraocular pressure measuring device of the present invention, and FIG. 2 is a schematic diagram illustrating the operation of a conventional intraocular pressure measuring device. ■...Axis 2...Cornea 3...Fluid pulse emitting means 4...Solenoid 5...Piston 6...Cylinder 7...Nozzle 20...Aiming light projection means 21... light emitting diode

Claims (1)

[Claims] A fluid pulse emitting means for emitting a fluid pulse toward the corneal surface from the axial direction of the device, an aiming light projecting means for projecting aiming light onto the corneal surface obliquely from the side of the axis, and the aiming light reflected from the corneal surface. An intraocular pressure measuring device comprising: aiming light detecting means for receiving light on the opposite side of the axis; and an output signal from the aiming light detecting means controls the operation of the fluid pulse emitting means. Fluid pulse firing control device.