CN203802441U - Flattening type tenonometer - Google Patents

Abstract

The utility model relates to an applanation tonometer, which relates to an intraocular pressure measuring device, in particular to a tonometer for accurately measuring intraocular pressure, which is suitable for glaucoma diagnosis. The purpose is to provide an applanation tonometer with short measurement time and high measurement accuracy. The applanation tonometer of the utility model amplifies the reaction force of the eyeball by ten times through a lever and transmits it to a mechanical sensor, so as to know the magnitude of the reaction force of the eyeball. When the eyeball does not touch the bottom surface of the frustum-round lens, the frustum-round lens will totally reflect part of the light from the light source to the light intensity detector, and when the eyeball touches the bottom surface of the frustum-round lens, the eyeball will prevent the total reflection of the contact area between the eyeball and the bottom surface of the frustum-round lens. In this way, the contact area can be obtained by comparing the light intensity before and after contact. Since both the light intensity detection and the mechanical detection can be detected instantaneously, the detection time is greatly shortened, and the shaking phenomenon caused by the long-time detection is prevented when the detector is held, which increases the accuracy of the measurement.

Description

applanation tonometer

technical field

The utility model relates to an intraocular pressure measuring device, in particular to an intraocular pressure meter for accurately measuring the intraocular pressure value, which is suitable for the diagnosis of glaucoma.

Background technique

Intraocular pressure is the pressure inside the eye, which refers to the pressure of the contents of the eyeball on the wall of the eyeball. The intraocular pressure of normal people is between 10 and 20mmHg (1mmHg=0.133kPa). Glaucoma is an irreversible blinding eye disease that causes visual impairment due to excessive intraocular pressure. Therefore, accurate determination of intraocular pressure is important for the diagnosis of glaucoma.

Various methods and corresponding devices are known for determining intraocular pressure. The applanation tonometer uses a probe to press the surface of the eyeball (such as the cornea) to a certain area and obtain the corresponding pressure, so as to obtain the intraocular pressure. For example, determination of intraocular pressure using a Goldmann-type applanation tonometer is an example of a non-invasive method. The device measures the force required to applanate a defined area of the eye under examination, in this case eg a circular surface area with a diameter of 3.06 mm. The device has a measuring body generally used for applanation, which includes a flat applanation surface, and the applied applanation force can be set by means of a knob. The device is then usually calibrated so that the intraocular pressure can then be read directly from the scale on the knob. This measurement method takes a long time to measure and has poor measurement accuracy.

Utility model content

The technical problem to be solved by the utility model is to provide an applanation tonometer with short measurement time and high measurement accuracy.

The utility model applanation tonometer comprises a shell, a light source, a small convex lens, a round table lens, a large convex lens, a light intensity detector, a lever and a mechanical sensor.

The housing is provided with a light source, a small convex lens, a table lens, a large convex lens, a light intensity detector, the lever and a force sensor, and the right end of the lever is hinged to the housing through a fulcrum shaft. The left end of the lever is fixed with a truncated lens. The axis of the frustum lens is perpendicular to the lever. A force sensor is provided at a position from the fulcrum shaft axis to the 1/10 of the frustum lens axis. The lower part of the mechanical sensor is fixedly connected with the shell, and the upper end of the mechanical sensor is in contact with the lever.

The diameter of the lower end surface of the frustum lens is smaller than that of the upper end surface, and the lower part of the frustum lens passes through the frustum hole of the shell. The frustum hole and the frustum lens are in clearance fit, and the upper end of the frustum lens is fixed to the lower end of the support cylinder. The support cylinder is coaxial with the frustum lens, a small convex lens is fixed in the support cylinder, and the support cylinder is made of opaque material. The small convex lens is coaxial with the support cylinder, and the upper end of the support cylinder is sealed and fixed with a baffle. The baffle is made of opaque material, the shape of the baffle matches the shape of the support cylinder, and the middle part of the lower end surface of the baffle is fixed with a light source. The light source is located in the support cylinder, and the light source is located at the focal point on the upper side of the small convex lens.

A support bin is fixed on the upper side of the baffle through a support rod. The bracket bin is a cylinder, and a large convex lens is fixed in the bracket bin through a large bracket. The large convex lens is coaxial with the small convex lens, and a light intensity detector is arranged at the focal point on the upper side of the large convex lens. The upper part of the light intensity detector is fixed to the upper end surface inside the bracket bin.

The diameter of the large convex lens is greater than or equal to the diameter of the upper end surface of the frustum of the cone lens. The diameter of the upper surface of the frustum lens is larger than the diameter of the support cylinder. The diameter of the support cylinder is larger than the diameter of the small convex lens. The diameter of the small convex lens is larger than the diameter of the lower end surface of the frustum of the cone lens.

In the applanation tonometer of the utility model, a forehead support seat is fixed at the left end of the casing. The forehead support seat includes a connecting column and a contact rod. The right end of the connecting column is fixedly connected with the left end of the shell, and the left end of the connecting column is fixedly connected with the upper end of the contact rod. The distance from the lower end surface of the contact rod to the lower end surface of the frustum lens is d1, and the distance from the eyeball to the forehead of an ordinary person is d2. The d1 is equal to d2.

The utility model relates to an applanation tonometer, wherein the upper end surface of the circular table lens is fixedly connected with the lower end of the cylindrical lens. The diameter of the cylindrical lens is greater than or equal to the diameter of the frustum lens. The lever is fixedly connected with the frustum lens through the cylindrical lens. The lower end of the support tube is fixedly connected with the upper end of the frustum lens through a cylindrical lens.

In the utility model of the applanation tonometer, the lower end of the contact rod is fixed with an arc-shaped backing plate. The arc backing plate is made of rubber or sponge material, and the arc backing plate is perpendicular to the contact rod.

The utility model relates to an applanation tonometer, wherein the mechanical sensor and the light intensity detector are connected with a processing module. The processing module is connected to the display screen, and the processing module, the display screen and the housing are fixedly connected.

In the applanation tonometer of the utility model, a battery is fixed inside the casing. The battery is connected with the display screen of the light intensity detector, the processing module and the force sensor.

In the applanation tonometer of the utility model, the support rod is made of light-transmitting material.

In the applanation tonometer of the utility model, the diameter of the small convex lens is the average of the diameters of the upper and lower end surfaces of the circular platform lens.

The difference between the applanation tonometer of the utility model and the prior art is that the applanation tonometer of the utility model first presses the eyeball through the lower end surface of the round table lens, so that it can receive the reaction force of the eyeball, and through the lever The reaction force of the eyeball is amplified ten times and transmitted to the mechanical sensor, so as to know the magnitude of the reaction force of the eyeball. Secondly, when the eyeball does not touch the lower end surface of the frustum-round lens, the frustum-round lens fully reflects part of the light from the light source to the light intensity detector, and when the eyeball touches the lower end surface of the frustum-round lens, the eyeball will prevent the contact area between the eyeball and the lower end surface of the frustum-round lens from being completely generated. Reflection, so the light intensity on the light intensity detector will decrease, so as to compare the light intensity before and after contact to know the contact area. The pressure inside the eyeball can be measured by depressing the area of the eyeball and the force of depressing the eyeball. Since both the light intensity detection and the mechanical detection can be detected instantaneously, the detection time is greatly shortened, and the shaking phenomenon caused by the long-time detection is prevented when the detector is held, which increases the accuracy of the measurement.

In the applanation tonometer of the utility model, since the eyeball is a relatively fragile part in human body organs, if excessive pressure is applied, the eyeball may be damaged. If too little pressure is applied, there may be shaking in the grip, resulting in inaccurate measurement results. Therefore, the utility model assists the examiner to hold the utility model stably through the forehead support seat, so that the measurement result is more accurate. The utility model prevents the unstable connection caused by the direct fixing of the lever and the side of the circular table lens by adding the cylindrical lens, or affects the effect of total reflection. The utility model can increase the contact area of the contact rod through the arc-shaped panel, thereby reducing the pressure, so that the contact rod is more stable and comfortable when it contacts the forehead of the detected person. The utility model receives the input signals of the mechanical sensor and the light intensity detector at the same time through the processing module, can calculate the pressure inside the eyeball detected at this time, and display it on the display screen. The utility model is powered by each electronic component of the battery, which enhances the movement detection capability of the utility model. The utility model uses a support rod made of a transparent material, which can prevent the light received by the light intensity detector from being weakened due to the support rod blocking the light emitted by total reflection. By controlling the diameter of the small convex lens, the utility model can minimize the passage of light, maximize the light intensity received by the light intensity detector as far as possible, and thus more obviously reflect the difference of light intensity changes.

The applanation tonometer of the present invention will be further described below in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 is a front view of an applanation tonometer;

Fig. 2 is the optical path diagram of the total reflection of the frustum lens shown in Fig. 1;

Fig. 3 is the optical path of the applanation tonometer described in Fig. 1;

Fig. 4 is the front view of the eyeball that is not pressed down by the cone lens in Fig. 1;

Fig. 5 is the front view of the depressed eyeball of the cone lens in Fig. 1;

FIG. 6 is a schematic diagram of the relationship between light intensity variation and applanation area in FIG. 1 .

Detailed ways

As shown in FIG. 1 , the applanation tonometer of the utility model includes a housing 1 , a light source 2 , a small convex lens 3 , a circular table lens 4 , a large convex lens 5 , a light intensity detector 6 , a lever 7 and a mechanical sensor 15 .

The housing 1 is provided with a light source 2, a small convex lens 3, a circular table lens 4, a large convex lens 5, a light intensity detector 6, a lever 7 and a force sensor 15, and the right end of the lever 7 is hinged to the housing 1 through a fulcrum shaft 71. A cylindrical lens 41 is fixed on the left end of the lever 7 . The diameter of the cylindrical lens 41 is greater than or equal to the diameter of the frustum lens 4 . The lower end of the cylindrical lens 41 is fixedly connected to the upper surface of the frustum lens 4 , and the axis of the cylindrical lens 41 is collinear with the axis of the frustum lens 4 . The axis of the frustum lens 4 is perpendicular to the lever 7 . A force sensor 15 is provided at a position 1/10 from the axis of the fulcrum shaft 71 to the axis of the frustum lens 4 . The lower part of the mechanical sensor 15 is fixedly connected with the housing 1 , and the upper end of the mechanical sensor 15 is in contact with the lever 7 .

The diameter of the lower end surface of the frustum lens 4 is smaller than that of the upper end surface, and the lower part of the frustum lens 4 passes through the frustum hole 16 of the housing 1 . The frustum hole 16 is in clearance fit with the frustum lens 4 , and the upper end of the cylindrical lens 41 is fixed to the lower end of the support cylinder 31 . The support tube 31 is coaxial with the cylindrical lens 41, and the small convex lens 3 is fixed in the support tube 31, and the support tube 31 is made of an opaque material. The small convex lens 3 is coaxial with the support tube 31 , and the upper end of the support tube 31 is sealed and fixed with a baffle plate 22 . The baffle 22 is made of opaque material, the shape of the baffle 22 matches the shape of the support cylinder 31 , and the middle part of the lower end surface of the baffle 22 is fixed with the light source 2 . The light source 2 is located in the support cylinder 31 , and the light source 2 is located at the focal point on the upper side of the small convex lens 3 .

A support bin 23 is fixed on the upper side of the baffle plate 22 through a support rod 21 . The support rod 21 is made of light-transmitting material. The bracket bin 23 is a cylinder, and a large convex lens 5 is fixed in the bracket bin 23 through a large bracket 51 . The large convex lens 5 is coaxial with the small convex lens 3, and a light intensity detector 6 is arranged at the focal point on the upper side of the large convex lens 5. The upper part of the light intensity detector 6 is fixed to the upper end surface inside the bracket bin 23 .

The mechanical sensor 15 and the light intensity detector 6 are connected to the processing module 13 . The processing module 13 is connected to the display screen 12 , and the processing module 13 and the display screen 12 are fixedly connected to the housing 1 . A battery 14 is fixed inside the casing 1 . The battery 14 is connected with the display screen 12 of the light intensity detector 6 , the processing module 13 and the force sensor 15 .

A forehead support seat 11 is fixed on the left end of the housing 1 . The forehead support base 11 includes a connecting column 111 and a contact rod 112 . The right end of the connecting column 111 is fixedly connected to the left end of the housing 1 , and the left end of the connecting column 111 is fixedly connected to the upper end of the contact rod 112 . The lower end of the contact rod 112 is fixed with an arc-shaped backing plate. The arc backing plate is made of rubber or sponge material, and the arc backing plate is perpendicular to the contact rod 112 . The distance from the lower end surface of the contact rod 112 to the lower end surface of the frustum lens 4 is d1, and the distance from the eyeball 91 to the forehead 92 of an ordinary person is d2. The d1 is equal to d2.

The diameter of the large convex lens 5 is greater than or equal to the diameter of the upper surface of the frustum lens 4 . The diameter of the upper surface of the frustum lens 4 is larger than the diameter of the support cylinder 31 . The diameter of the support cylinder 31 is larger than the diameter of the small convex lens 3 . The diameter of the small convex lens 3 is larger than the diameter of the lower end surface of the frustum lens 4 .

When in use, the tester holds the housing 1 and presses the arc-shaped backing plate on the contact rod 112 against the forehead 92 . Then the utility model is energized, as shown in Figure 2, the divergent light of the light source 2 is refracted into parallel light by the small convex lens 3. As shown in FIG. 3 , the parallel light is totally reflected twice by the side of the frustoconical lens 4 and then shoots upward to the outer ring of the large convex lens 5 . The large convex lens 5 parallelizes the light after two total reflections onto the light intensity detector. At this time, the light intensity detector 6 knows the magnitude of the total reflection light intensity. As shown in Fig. 4 and Fig. 5, the lower end surface of the round platform lens 4 is slowly pressed down on the eyeball 91, and now the mechanical sensor 15 knows the magnitude of the reaction force of the eyeball 91 through the lever 7.

As shown in FIG. 6 , the radius of the upper end surface of the frustoconical lens 4 is R2 , and the radius of the lower end surface is R1 . R0=(R1+R2)/2, the angle between the side surface and the lower bottom surface is α, where β=180°-2α, and the intensity of the incident parallel light is E0, then the center of the lower bottom surface on the lower bottom surface is a circle with a radius of r The light intensity E1 on is:

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; r</span>}}$

When the light is reflected to the upper bottom surface, the corresponding light intensity on the circle with the center of the upper bottom surface as the center radius r2 is:

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; r</span>}}{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

in:

r ₁ =R ₀ -rcosβ

r ₂ =R ₀ +rcosβ

From the above formula, the reduced luminous flux can be calculated when the radius of the pressing plane is R:

At this time, the processing module 13 calculates the pressure inside the eyeball 91 according to the force sensor 15, the light intensity detector 6 and this formula, and then transmits it to the display screen 12 to complete the detection.

The above-mentioned embodiments are only described to the preferred implementation of the utility model, and are not limited to the scope of the utility model. Various modifications and improvements made should fall within the scope of protection determined by the claims of the utility model.

Claims (8)

1. An applanation tonometer is characterized in that: comprising shell (1), light source (2), small convex lens (3), round table lens (4), large convex lens (5), light intensity detector (6) ), lever (7) and force sensor (15); The housing (1) is provided with a light source (2), a small convex lens (3), a circular table lens (4), a large convex lens (5), a light intensity detector (6), the lever (7) and a mechanical sensor ( 15), the right end of the lever (7) is hingedly connected with the housing (1) through the fulcrum shaft (71), and the left end of the lever (7) is fixed with a frustum lens (4), and the axis of the frustum lens (4) is perpendicular to the lever (7) A force sensor (15) is provided at 1/10 of the axis of the fulcrum shaft (71) to the axis of the frustum lens (4), the lower part of the force sensor (15) is fixedly connected to the housing (1), and the force sensor (15) The upper end is in contact with the lever (7); The diameter of the lower end surface of the frustum-round lens (4) is smaller than the upper end surface, and the lower part of the frustum-round lens (4) passes through the frustum hole (16) of the housing (1), and the frustum hole (16) is in clearance fit with the frustum lens (4), and the frustum The upper end of the lens (4) is fixed with the lower end of the support tube (31), and the support tube (31) is coaxial with the truncated lens (4), and the small convex lens (3) is fixed in the support tube (31), and the support tube (31) consists of Made of opaque material, the small convex lens (3) is coaxial with the support cylinder (31), the upper end of the support cylinder (31) is sealed and fixed with a baffle (22), and the baffle (22) is made of opaque material Made, the shape of the baffle (22) matches the shape of the support tube (31), the middle part of the lower end surface of the baffle (22) is fixed with a light source (2), and the light source (2) is located in the support tube (31), the light source (2) located at the focal point on the upper side of the small convex lens (3); The upper side of the baffle plate (22) is fixed with a bracket bin (23) through a support rod (21), the bracket bin (23) is a cylinder, and a large convex lens is fixed in the bracket bin (23) through a large bracket (51) (5), the large convex lens (5) is coaxial with the small convex lens (3), and a light intensity detector (6) is provided at the focal point on the upper side of the large convex lens (5), and the light intensity detector (6) top and The upper end surface inside the bracket storehouse (23) is fixed; The diameter of the large convex lens (5) is greater than or equal to the diameter of the upper surface of the frustum lens (4), the diameter of the upper surface of the frustum lens (4) is greater than the diameter of the support tube (31), and the diameter of the support tube (31) is greater than that of the small convex lens ( 3) Diameter, the diameter of the small convex lens (3) is greater than the diameter of the lower end surface of the frustum of the round lens (4). 2. The applanation tonometer according to claim 1, characterized in that: a forehead support seat (11) is fixed at the left end of the housing (1), and the forehead support seat (11) includes a connecting column (111) and the contact rod (112), the right end of the connecting rod (111) is fixedly connected to the left end of the housing (1), the left end of the connecting rod (111) is fixedly connected to the upper end of the contact rod (112), and the lower end of the contact rod (112) is connected to The distance from the lower end surface of the frustum lens (4) is d1, and the distance from the eyeball (91) to the forehead (92) of an ordinary person is d2, and the d1 is equal to d2. 3. The applanation tonometer according to claim 2, characterized in that: the upper end surface of the truncated circular lens (4) is fixedly connected to the lower end of the cylindrical lens (41), and the diameter of the cylindrical lens (41) is greater than or equal to The diameter of the frustum lens (4), the lever (7) is fixedly connected with the frustum lens (4) by the cylindrical lens (41), and the lower end of the support tube (31) is connected to the upper end of the frustum lens (4) by the cylindrical lens (41). Fixed connection. 4. The applanation tonometer according to claim 2, characterized in that: the lower end of the contact rod (112) is fixed with an arc-shaped backing plate, the arc-shaped backing plate is made of rubber or sponge material, and the arc-shaped backing plate is made of rubber or sponge. Shape backing plate is vertical with contact bar (112). 5. The applanation tonometer according to claim 4, characterized in that: the mechanical sensor (15), the light intensity detector (6) are connected to the processing module (13), and the processing module (13) It is connected with the display screen (12), and the processing module (13), the display screen (12) is fixedly connected with the shell (1). 6. The applanation tonometer according to claim 5, characterized in that: a battery (14) is fixed inside the casing (1), and the battery (14) and the display screen of the light intensity detector (6) (12), processing module (13), mechanical sensor (15) are connected. 7. The applanation tonometer according to claim 6, characterized in that: the support rod (21) is made of light-transmitting material. 8 . The applanation tonometer according to claim 7 , characterized in that: the diameter of the small convex lens ( 3 ) is the average of the diameters of the upper and lower end surfaces of the frustum lens ( 4 ).