KR20230095463A - Non-contact tonometer - Google Patents

Abstract

Disclosed is a non-contact tonometer capable of accurately determining whether a distance between an eye to be examined and the non-contact tonometer is a distance capable of measuring intraocular pressure using an infrared light source (Aim Led). A spray nozzle 32 for spraying compressed air to the eye E to be examined is located on the left and right sides of the tip of the spray nozzle 32, and irradiates infrared light to the center of the cornea of the eye E to be examined, respectively. It includes a pair of infrared light sources 15 and an optical detection element 18 for detecting infrared light reflected from the cornea of the eye E to be examined, wherein the infrared light incident on the center of the cornea of the eye E to be examined is When superimposed and observed as a single point, a non-contact tonometer is provided in which the injection nozzle 32 is positioned at a predetermined distance from the eye E to be examined to measure the intraocular pressure.

Description

Non-contact tonometer {Non-contact tonometer}

The present invention relates to a non-contact tonometer, and more particularly, to a non-contact tonometer capable of accurately determining whether a distance between an eye to be examined and the non-contact tonometer is a distance capable of measuring intraocular pressure using an infrared light source (Aim Led).

Intraocular pressure (IOP) is a pressure acting on the eyeball by aqueous humor, which is a solution that fills the space between the cornea and the lens of the eyeball, and the level of normal intraocular pressure is generally about 10 to 21 mmHg. A normal level of intraocular pressure plays a role in maintaining the shape and function of the eyeball, but abnormality in the production and drainage of aqueous humor occurs, and when the intraocular pressure becomes abnormally high, it damages the optic nerve fiber layer of the retina or causes severe diseases such as glaucoma. As a result, you may lose your eyesight. Therefore, accurate intraocular pressure measurement is very important for early detection and treatment of ophthalmic diseases.

A tonometer for measuring intraocular pressure may be classified into a contact-type tonometer and a non-contact-type tonometer according to whether the tonometer is in contact with the cornea. Here, the non-contact tonometer sprays air compressed by a solenoid and a piston drive to the cornea of an eye to be examined at a certain distance through a small nozzle, presses a certain area of the cornea with air pressure (applanation), and measures the time required for applanation. Intraocular pressure is calculated from the applied air pressure. That is, when the intraocular pressure is high, the deformation of the cornea is small, and when the intraocular pressure is low, the deformation of the cornea is relatively large. It is more convenient and hygienic compared to the contact-type tonometer because it does not contact the cornea, and the examination is performed instantaneously.

Korean Patent Publication No. 10-2013-0107918 discloses a non-contact intraocular pressure measuring device and an intraocular pressure calculation method. A typical non-contact tonometer includes an alignment monitoring system, an applanation monitoring system, a compressed air generating unit, and a control unit. The alignment observation system includes a gaze projection light source for radiating gaze-guided light for fixing the gaze of the eye to be examined, an alignment light source for radiating alignment light to the eye to be examined, and an alignment light source for reflecting the gaze-guided light in the direction of the eye to be examined and reflected from the eye to be examined. It includes a reflection mirror that transmits light and an optical detection element that detects the alignment light reflected from the eye to be examined. The applanation observation system includes an applanation light source that radiates applanation measurement light to the cornea of the eye to be examined, and a photodetector that detects applanation measurement light reflected from the cornea with different intensities depending on the deformation state of the cornea. The compressed air generator includes a solenoid for driving a piston, a spray nozzle for generating compressed air by driving the piston and injecting the generated compressed air into the eye to be examined, and detecting air pressure of the compressed air sprayed from the spray nozzle. Contains a pressure sensor. The control unit controls the driving of the piston through the solenoid to adjust the supply of compressed air, receives the deformation state of the cornea detected by the optical detector and the pressure of the compressed air detected by the pressure sensor, Calculate intraocular pressure.

In a conventional non-contact tonometer, there is a problem in that an error occurs in a measured value due to an error in measuring the distance between the eye to be tested and the non-contact tonometer, which is measured at an intermittent distance or measured in a state where the aiming point is shifted.

Therefore, an object of the present invention is to visually determine the exact distance for measuring the intraocular pressure through an optical setup of the distance between the center of the cornea of the eye to be examined and the injection nozzle using an infrared light source (IR light source) (Aim Led) , To provide a non-contact tonometer capable of minimizing an error value.

Another object of the present invention is to provide a non-contact tonometer capable of minimizing an error value by using a distance determination method of an eye to be examined using overlapping images of observed infrared light sources (IR light sources).

In order to achieve the above object, the present invention is a spray nozzle 32 for spraying compressed air to the eye E to be examined, located on the left and right sides of the tip of the spray nozzle 32, and the cornea of the eye E to be examined. A pair of infrared light sources 15 for irradiating infrared light to the center, respectively, and a photodetection element 18 for detecting infrared light reflected from the cornea of the eye E to be examined; Provided a non-contact tonometer in which the injection nozzle 32 is located at a predetermined distance from the eye E to be examined when the infrared light incident to the center of the cornea is overlapped and observed as a single point do.

The non-contact tonometer according to the present invention can minimize an error value by secondarily observing the distance between the eye to be tested and the tonometer using a digital image using an infrared light source (Aim Led).

1 is a view showing a non-contact tonometer according to an embodiment of the present invention.
FIG. 2 is a diagram showing an image of infrared light detected by an optical detection device according to a distance between an eye to be examined and a non-contact tonometer in a non-contact tonometer according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

The non-contact tonometer according to the present invention is a device for measuring the intraocular pressure of the eye to be examined by injecting compressed air into the center of the eye to be examined at a certain distance away.

The mechanical configuration of the non-contact tonometer according to the present invention is the same as that of a conventional intraocular pressure measuring device, but in order to determine the distance between the eye to be examined E and the intraocular pressure measuring device (specifically, a spray nozzle), the An infrared light source 15 irradiated to the center of the cornea and a photodetection element 18 for detecting infrared light reflected from the eye to be examined are added.

1 is a view showing a non-contact tonometer according to an embodiment of the present invention, and as shown in FIG. 1, the non-contact tonometer according to the present invention has a spray nozzle 32 for spraying compressed air to the eye E to be examined. ), a pair of infrared light sources 15 located on the left and right sides of the front end of the injection nozzle 32 and irradiating infrared light to the center of the cornea of the eye E to be examined, respectively, and the cornea of the eye E to be examined A photodetection device that detects the reflected infrared light and determines whether the spray nozzle 32 and the center of the cornea of the eye E to be examined are located at a predetermined distance for measuring the intraocular pressure according to the image of the detected infrared light ( 18).

The infrared light irradiated from the infrared light source (IR light source) 15 is an indicator for determining whether the tonometer (specifically, the injection nozzle) and the eye E to be examined are located at a predetermined distance capable of measuring intraocular pressure. do. The infrared light source 15 is a pair of light sources located on the left and right sides of the front end of the spray nozzle 32. The infrared light source 15 simultaneously irradiates the center of the cornea of the eye E to be examined, and forms an image on the cornea of the eye E to be examined. It is preferable to use an Aim LED as the infrared light source 15, and specifically, it does not interfere with the path of other light sources (eg, the gaze projection light source 12, the applanation light source 20, etc. described below), It may be located in an inclined direction with respect to the horizontal line of the injection nozzle 32. When the infrared light source 15 according to the present invention is irradiated to the center of the cornea of the eye E to be examined, it may have an arbitrary angle a. The angle varies depending on the designed optical system structure, and in general, when detected at an incident angle within 1 ° to 2 °, it can be determined as a valid signal.

The light detecting element 16 includes an imaging device and the like. The light detection element 16 detects infrared light reflected from the cornea of the eye E to be examined, and provides information on the distance between the eye E to be examined and the spray nozzle 32 based on the detected infrared light as an image. or as a digital image. Specifically, it is determined whether the injection nozzle 32 is located at a predetermined distance for measuring the intraocular pressure of the eye E to be examined according to the observed infrared light image or digital image.

2 is a view showing images 19a and 19b of infrared light observed from an optical detection device 18 according to a distance between an eye E to be examined and a noncontact tonometer in a noncontact tonometer according to an embodiment of the present invention. , As shown in FIG. 2, the number of infrared rays observed is different depending on the positions of the eye E to be examined and the non-contact tonometer.

Specifically, when the injection nozzle 32 of the non-contact tonometer is located at a predetermined distance (a measurable distance for measuring intraocular pressure) from the eye E to be examined, and the aiming position is correct, the left side of the tip of the injection nozzle, When the infrared light source 15 located on the right radiates infrared light to the center of the cornea of the eye E to be examined, the infrared light is superimposed, and the image 19a is viewed as a single point on the light detection element 18 It is observed as (see (a) in FIG. 3).

On the other hand, if the aiming position is distorted because the injection nozzle 32 of the non-contact tonometer is located closer or farther than a predetermined distance (a measurable distance for measuring intraocular pressure) from the eye to be examined, the Infrared light incident to the center of the cornea does not overlap but intersects with each other, and is observed as an image 19b shown as two dots (see (b) of FIG. 3).

The predetermined distance refers to a distance between a noncontact tonometer for accurately measuring the intraocular pressure of the eye to be examined and the eye to be examined, and generally varies depending on a designed optical system structure.

The position of the eye to be examined E or the non-contact tonometer (injection nozzle) can be adjusted so that the non-contact tonometer (injection nozzle 32) can be located at a predetermined distance from the eye to be examined E to measure the intraocular pressure, A control unit including a driving means for driving the non-contact tonometer may be included. For example, if infrared light incident on the center of the cornea of the eye to be examined is observed as two points, it can be determined that the position of the non-contact tonometer E is farther or closer than a predetermined distance from the eye to be examined, The control unit may position the noncontact tonometer at an accurate position from the eye to be examined by driving the noncontact tonometer to be positioned far or near, and adjusting the position until the infrared light is seen as a single point.

The injection nozzle 32 may be used without limitation as long as it has a structure capable of injecting compressed air to the eye E to be examined. For example, the injection nozzle may include a piston driven by a solenoid, compress internal air by reciprocating driving of the piston, generate compressed air, and spray the generated compressed air to the eye to be examined.

The non-contact tonometer according to the present invention generates gaze-guided light (for example, infrared rays (IR rays), etc.) for inducing fixation of the gaze of the eye to be examined, forms an image on the retina of the eye to be examined, and gazes to fix the gaze of the eye to be examined. The projection light source 12 irradiates a pair of alignment indicator lights to the eye to be examined, and the pair of irradiated alignment indicator lights forms an image as two index images at positions symmetrical to the central axis direction of the eye to be examined, so that the upper, lower, left, and right directions are formed. An alignment indicator light source (not shown in the figure) that can be used for alignment detection and reflecting the line-of-sight guided light toward the eye to be examined, transmitting infrared light reflected from the eye to be examined, and transmitting it to the photodetection element 18 A reflection mirror 16 may be further included.

The non-contact tonometer according to the present invention further includes an applanation observation unit including an applanation light source for radiating applanation measurement light to the cornea of the eye to be examined and a photodetector for detecting the applanation measurement light reflected from the cornea of the eye to be examined. Intraocular pressure, etc. can be calculated.

Therefore, the noncontact tonometer according to the present invention can determine whether the eye to be examined and the noncontact tonometer are located at a predetermined distance by observing the infrared light reflected from the cornea of the eye E to be examined, thereby locating the noncontact tonometer at a more accurate position. so that the eye to be examined can be examined.

Looking at the operation of the non-contact tonometer according to the present invention, first, the gaze-guided light emitted from the gaze projection light source 12 is formed on the retina of the eye E to be examined through the reflection mirror 16, thereby fixing the gaze of the eye to be examined. Infrared light is respectively incident from a pair of infrared light sources 15 positioned at a predetermined distance from the front end of the spray nozzle 32 to the center of the cornea of the eye E to be examined. Infrared light reflected from the center of the cornea of the eye E to be examined passes through the reflection mirror 16 and is incident on the light detecting element 18 such as an imaging device.

Depending on the infrared light observed by the light detection element 18, secondary working distance information is obtained. Specifically, when the infrared light is observed as a single point by the light detection element 18, a predetermined distance at which the non-contact tonometer (specifically, the spray nozzle 32) can measure the intraocular pressure from the eye E to be examined. It can be seen that it is located in

When the infrared light is observed as two points by the optical detection element 18, it is determined that the non-contact tonometer (specifically, the injection nozzle 32) is out of a predetermined distance capable of measuring the intraocular pressure from the eye E to be examined. In detail, it may be determined that the distance between the non-contact tonometer and the center of the cornea of the eye E to be examined is located closer to or farther than a predetermined distance capable of measuring intraocular pressure.

When the infrared light is observed as two points by the light detecting element 18, the cornea of the eye E to be examined is observed on the x-plane (direction horizontal to the moving direction of the compressed air) while observing the position of the observed infrared light. The position of the eye to be examined E or the non-contact tonometer is adjusted so that one infrared light is located at the center of .

When a predetermined distance is maintained between the center of the cornea of the eye E to be examined and the spray nozzle 32, the compressed air is sprayed to the eye E to be examined. At this time, the applanation measurement light is irradiated to the cornea of the eye E to be examined, and the applanation measurement light reflected from the cornea of the eye E to be examined is detected by the photodetector, such as the deformation state of the cornea of the eye E to be examined, intraocular pressure, etc. to measure

A general non-contact tonometer can obtain primary distance information using a distance sensor such as a PSD or a line sensor. However, the non-contact tonometer according to the present invention further includes an infrared light source 15 in the configuration of a general non-contact tonometer, thereby further combining the distance information result observed from the infrared light reflected from the center of the cornea of the eye to be examined, Since the position of the non-contact tonometer (spray nozzle 32) can be accurately determined, the eye to be examined can be more accurately observed and inspected.

Claims (5)

an injection nozzle 32 for injecting compressed air to the eye E to be examined;
a pair of infrared light sources 15 positioned on the left and right sides of the tip of the spray nozzle 32 and irradiating infrared light to the center of the cornea of the eye E to be examined; and
a light detection element 18 for detecting infrared light reflected from the cornea of the eye E to be examined;
When the infrared light incident on the center of the cornea of the eye E to be examined overlaps and is observed as a single point, the injection nozzle 32 is located at a predetermined distance from the eye E to be examined for measuring the intraocular pressure. That is, a non-contact tonometer. The method according to claim 1, wherein when the infrared light incident on the center of the cornea of the eye E to be examined is observed as two dots in the light detecting element 18, the method for measuring intraocular pressure from the eye E to be examined is performed. A non-contact tonometer in which the injection nozzle 32 is located closer or farther than a predetermined distance. The non-contact tonometer according to claim 1, wherein the infrared light source (15) is an aim led. 2. The noncontact tonometer according to claim 1, further comprising a reflection mirror (16) for transmitting infrared light reflected from the eye (E) to be transmitted to an optical detection element (18). The method of claim 1, wherein when the compressed air is sprayed from the injection nozzle 32 to the eye E to be examined, the applanation measurement light is radiated to the cornea of the eye E to be examined to observe the eye E to be examined. The non-contact tonometer further comprises an applanation light source 20 for generating light and an optical detector 22 for detecting the applanation measurement light reflected from the cornea of the eye to be examined.

Images