CN102920428B - Portable tenonometer - Google Patents

Abstract

The invention relates to a contact type portable intraocular pressure measuring device. The portable tonometer of the present invention comprises a housing, a probe, a first light source, an image sensor, a strain gauge, a microprocessor, a power supply and a display memory, the left end of the probe is circular and made of transparent optical material, and the right end of the probe is fixed Install at least two elastic beams, each elastic beam is perpendicular to the axis of the probe, the outer end of each elastic beam is fixedly connected to the left end of the housing, strain gauges are installed on the elastic beams, and the image sensor is located on the right side of the probe , the axis of the receiving window of the image sensor coincides with the axis of the probe, the diameter of the receiving window is equal to or smaller than the diameter of the left end face of the probe, the first light source is arranged around the receiving window, the strain gauge, the image sensor and the display memory are all connected with the microprocessor connect. The present invention can continuously and dynamically detect a plurality of intraocular pressure values, effectively avoiding errors in measurement when the measuring device shakes or the person to be measured shakes.

Description

Portable Tonometer

technical field

The invention relates to an intraocular pressure measuring device, in particular to a contact type portable intraocular pressure measuring device.

Background technique

Intraocular pressure is the pressure per unit volume of the eyeball wall (aqueous humor, lens, vitreous body, blood) acting on the eyeball wall. Long-term elevated intraocular pressure will lead to optic nerve ischemia, lower tolerance at the same intraocular pressure level, and cause neurodegeneration. Irreversible visual field defect. Intraocular pressure is often closely related to various eye diseases. At present, glaucoma is the second irreversible blinding eye disease in the world. According to statistics, there are more than 67 million primary glaucoma patients in the world. At present, there are at least 5 million glaucoma patients in my country, of which 790,000 are blind . The prevalence of this eye disease increases with age. Glaucoma is characterized by pathological elevated intraocular pressure, irreversible optic atrophy, and visual field defect, which seriously affect the quality of life of patients. In my country, the incidence rate is 0.21%-1.64%, and the blindness rate is 10%-20%. It is one of the main diseases that endanger the health of middle-aged and elderly people (55-70 years old). The most common and effective way to prevent glaucoma is to measure the patient's intraocular pressure and use drugs to control the increase in intraocular pressure.

Traditionally, there are two methods for measuring intraocular pressure with a tonometer, namely implantable and non-implantable. Although the implantable type can directly measure the intraocular pressure, it is difficult to be operable clinically, so the clinical must rely on non-implantable indirect measurement methods. Tonometers in the usual sense can be defined as non-implantable indirect measurements. There are two main types of non-implantable indirect measurements that dominate today, one is the indentation tonometer, and the other is the applanation tonometer. The indentation tonometer usually reaches the eyeball through the jet of air from the end of the probe, and obtains the intraocular pressure at the moment the eyeball is indented. This method avoids the cross-infection of some diseases because there is no direct contact between the instrument and the eyeball, and also avoids anesthesia to the cornea. However, due to its expensive cost and lack of good precision, it is difficult for the operator The operating skills required are high, unnecessary damage to the cornea and the need for frequent maintenance prevent it from being widely used clinically, such as the Schiotz tonometer; the applanation tonometer presses the surface of the eyeball through the probe (such as the cornea) to a certain area and obtain the corresponding pressure, so as to obtain the intraocular pressure.

Chinese patent CN202161301U discloses an applanation tonometer, as shown in Figure 1, including a measuring head 1', a measuring connecting rod 2', a swing rod 3', a swing shaft 4', a balance rod 5', and a swing arm 6' , spring, rack 8', gear 16', gear shaft 9', knob 10', shell supporting device 17', and an elastic part 11' is arranged between the measuring connecting rod 2' and the swing shaft 4', the elastic part Both ends of 11' are fixedly connected to the measuring connecting rod 2' and the swing shaft 4', the strain gauge 12' is fixedly connected to the elastic part 11', and the strain gauge 12' is electrically connected to the strain gauge measurement and display device 13 to display the strain Measurement results for sheet 12'. When measuring, the measuring head 1' is tilted toward the person being measured by rotating the knob 10', so as to ensure that the measuring head 1' will not impact the cornea of the person being measured when measuring. Rotating the knob 10' can rotate the gear shaft 9', the gear 16' on the gear shaft 9' drives the rack 8' to move, and the rack 8' pushes the swing arm 6' to move, thereby driving the swing rod 3' to make the swing The lever 3' rotates around the pivot axis 4'. The elastic part 11', the measuring connecting rod 2', and the measuring head 1' rotate together with the swing shaft 4', so that the measuring head 1' is flattened to the cornea. Exactly flattened cornea can be judged by looking through the slit lamp microscope outside the tonometer. At this time, the strain gauge 12' extracts the deformation of the elastic part 11', and then through the amplification, analog-to-digital conversion, and calculation of the strain gauge measurement and display device 13', the measurement result is obtained and displayed. However, this tonometer is a Goldman-type tonometer. When measuring with this method, it can only measure the intraocular pressure of a specific applanation area, that is, only measure the intraocular pressure value once. When the measurer is not skilled, it will cause When the measuring device shakes, or the person being measured shakes due to nervousness, it may cause errors in the measurement results.

Contents of the invention

The technical problem to be solved by the present invention is to provide a portable tonometer with simple structure and easy operation, which can continuously and dynamically detect multiple intraocular pressure values when measuring intraocular pressure, effectively avoiding shaking of the measuring device or shaking of the person being measured , the measurement error occurs.

The portable tonometer of the present invention comprises a housing, a probe, a first light source, an image sensor, a strain gauge, a microprocessor, a power supply and a display memory, the left end of the probe is circular and made of transparent optical material, and the right end of the probe is fixed At least two elastic beams are installed, each elastic beam is perpendicular to the axis of the probe, the outer end of each elastic beam is fixedly connected to the left end of the housing, strain gauges are installed on the elastic beams, the first light source, image sensor, The microprocessor, power supply and display memory are all installed in the housing, the image sensor is located on the right side of the probe, the axis of the receiving window of the image sensor coincides with the axis of the probe, and the diameter of the receiving window of the image sensor is equal to or smaller than the diameter of the left end surface of the probe , the first light source is arranged around the receiving window, the microprocessor, the display memory, the strain gauge, the image sensor and the first light source are all connected to the power supply, and the strain gauge, the image sensor and the display memory are all connected to the microprocessor.

In the portable tonometer of the present invention, a convex lens is arranged on the left side of the receiving window of the image sensor, and the central axis of the convex lens coincides with the axis of the probe.

The portable tonometer of the present invention, wherein the right end of the probe is fixedly fitted with an annular carrier, the inner end of each elastic beam is fixedly mounted on the probe through the carrier, and at least two support beams are arranged on the left end of the housing, and the support beam and The elastic beams are parallel, each support beam is located on the left side of the elastic beam, and an adjusting screw for adjusting the distance between the support beam and the carrier is installed at the inner end of the support beam.

In the portable tonometer of the present invention, the first light source is in the shape of a ring and is set on the receiving window of the image sensor.

In the portable tonometer of the present invention, the probe is made of glass or resin.

The portable tonometer of the present invention also includes a horn, which is fixedly installed in the shell and connected with the microprocessor.

The portable tonometer of the present invention also includes a second light source, a display and a half mirror, the display and the half mirror are fixedly installed in the housing, the half mirror is located on the left side of the convex lens, the axis of the probe passes through the half mirror, and the half mirror The axis of the probe is at an angle of 45 degrees to the axis of the probe. The second light source is located directly above or directly below the half mirror. The second light source is a point light source. The light emitted by the second light source is reflected by the half mirror and then incident on the probe. At the center of the left end face, the image sensor is connected to the display.

The difference between the portable tonometer of the present invention and the prior art is that the present invention emits light through the first light source. When the left end surface of the probe is not in contact with the apex of the quasi-dome cornea of the eyeball, the vertically incident light is refracted on the side surface and the left end surface of the probe. , into the air, forming reflected light on the surface of the eyeball and other objects, and part of the reflected light enters the probe from the left end of the probe together with the ambient light. After the light passes through the probe, it enters the image sensor, and the image sensor detects The white area is the white area. When the left end surface of the probe comes into contact with the vertex of the quasi-dome cornea of the eyeball, the part in contact with the probe is the eyeball. The light from the first light source at the contact part between the left end surface of the probe and the eyeball enters the eyeball. At the same time, there is no light at the left end surface of the probe that is in contact with the eyeball and enters the image sensor after passing through the probe. The image sensor detects a dark circular image. When the probe continues to be pressed down, the applanation area gradually increases, and the dark circle detected by the image sensor The diameter of the shape image gradually increases. In the process of probe pressing, the elastic beam is bent due to the force of the probe, and the strain gauge installed on the elastic beam can obtain the deformation of the elastic beam, which is transmitted after amplification and digital-to-analog conversion. Give the microprocessor, the microprocessor can obtain the applanation force after calculation, and the effective applanation area and applanation force can be continuously and dynamically measured through the image sensor and strain gauge, and after passing through the microprocessor, it will be displayed and stored by the display memory . Therefore, when the device is measuring intraocular pressure, it can continuously and dynamically detect multiple intraocular pressure values according to the program set on the microprocessor, effectively avoiding errors in measurement when the measuring device is shaken or the person being measured shakes.

The present invention will be further described below in conjunction with accompanying drawing.

Description of drawings

Fig. 1 is the front view of the tonometer of prior art;

Fig. 2 is the front view of portable tonometer of the present invention;

Fig. 3 is the left side view of the first light source and the receiving window of the image sensor of the portable tonometer of the present invention;

Fig. 4 is the front view when the portable tonometer of the present invention is in contact with the eyeball;

Figure 5a is the image detected by the image sensor (the diameter of the dark circular image is 2 mm);

Figure 5b is the image detected by the image sensor (the diameter of the dark circular image is 4 mm);

Figure 5c is the image detected by the image sensor (the diameter of the dark circular image is 6 mm);

Fig. 6 is a schematic diagram of the circuit connection relationship of the portable tonometer of the present invention.

Detailed ways

As shown in Figure 2, the portable tonometer of the present invention includes a housing 1, a probe 2, a first light source 3, a second light source 4, an image sensor 5, a strain gauge 6, a microprocessor 7, a power supply 8, a display 9 and a display memory 10. The shell 1 is cylindrical, the left half of the probe 2 is a truncated cone, the right half of the probe 2 is cylindrical, and the probe 2 is made of transparent optical material. The probe 2 is located on the left side of the housing 1 .

As shown in Fig. 4, an annular carrier 11 is fixedly set on the outer peripheral surface of the right end of the probe 2, and two elastic beams 12 are fixedly installed on the carrier 11 by bolts, and the two elastic beams 12 are perpendicular to the axis of the probe 2, And the two elastic beams 12 are arranged symmetrically with respect to the axis of the probe 2, the outer end of each elastic beam 12 is welded on the inner wall of the left end of the housing 1, and strain gauges 6 are installed on the right end surfaces of the two elastic beams 12 , The strain gauge 6 is connected with the microprocessor 7 . In this embodiment, a pair of strain gauges 6 are used. Under the condition of meeting the installation requirements, the size and precision of the strain gauges 6 should be selected as large as possible to meet the force measurement requirements in the linear range. The advantage of the strain gauge is that under the same pressure, the passing displacement is small, and it can provide a relatively high output voltage; the price is cheap, and the performance is stable; compared with other tonometers, the operation process can be simplified. Two supporting beams 13 are arranged on the left end of the housing 1, the supporting beams 13 are parallel to the elastic beams 12, each supporting beam 13 is located on the left side of the elastic beams 12, and an adjustable supporting beam 13 is installed at the inner end of the supporting beams 13 An adjustment screw 14 for the distance from the carrier 11. Of course, multiple support beams 13 may also be provided, or multiple support beams 13 may be connected together to form a circular ring. The purpose of setting the support beam 13 is to further fix the effect of the balance probe and the elastic beam, and at the same time, the distance between the carrier 11 and the support beam 13 can be adjusted by adjusting the screw 14, so as to achieve the purpose of adjusting the initial value of the measuring force. When measuring, by turning the adjusting screw 14, the right end of the adjusting screw 14 is pressed on the carrier 11, and the adjusting screw 14 applies a preload to the elastic beam 12. By adjusting the size of the preload, the self-weight of the probe 2 can be balanced, so that the strain gauge The measured applanation force is more accurate.

Many viruses can be transmitted through tears, for example, prion (prion) found in tears is infectious and can be transmitted from one person's eyes to another through contact with tears, and it has been proved that infected objects are not easily infected. Therefore, the probe 2 is installed on the elastic beam 12 through the carrier 11. After each measurement, the bolt connecting the elastic beam 12 and the carrier 11 is unscrewed, and the probe 2 can be easily replaced. Probe 2 is made of optical glass. In order to reduce the cost, the material of the probe 2 can be made of low-cost resin, and the probe 2 can be molded with a simple mold, which can be mass-produced.

The first light source 3 , the image sensor 5 , the strain gauge 6 , the microprocessor 7 , the power supply 8 , the display 9 and the display memory 10 are all fixedly installed in the casing 1 . The image sensor 5 is located on the right side of the probe 2, the axis of the receiving window 15 of the image sensor 5 coincides with the axis of the probe 2, and the diameter of the receiving window 15 of the image sensor 5 is equal to or smaller than the diameter of the left end face of the probe 2. A convex lens 16 is arranged on the left side of the receiving window 15 , the central axis of the convex lens 16 coincides with the axis of the probe 2 , and the diameter of the receiving window 15 in this embodiment is equal to the diameter of the left end surface of the probe 2 . As shown in FIG. 3 , the first light source 3 is in the shape of a ring and is set on the receiving window 15 of the image sensor 5 . The first light source 3 is used to generate incident light, and it can be a light emitting diode emitting visible light, an incandescent lamp or a fluorescent lamp. The image sensor 5 can be a black and white or color CCD or CMOS device, which contains an analysis circuit for acquiring the geometric parameters (area) of the dark circular image 17 as shown in FIG. 5a.

The second light source 4 is also fixedly installed in the housing 1, the half mirror 18 is positioned on the left side of the convex lens 16, and the half mirror 18 is positioned on the axis of the probe 2, and the axis of the half mirror 18 is 45 degrees to the axis of the probe 2 angle, the second light source 4 is located directly above or directly below the half mirror 18, the second light source 4 is a green point light source, and the light emitted by the second light source 4 can be incident on the left end of the probe 2 after being reflected by the half mirror 18 In the center position of the surface, the second light source 4 is located directly above the half mirror 18 in this embodiment, and the half mirror 18 is inclined upward from left to right. Display 9 is connected to image sensor 5 . By setting the second light source 4, the half mirror 18 and the display 9, it can be judged whether the axis of the probe 2 is coaxial with the axis of the eyeball. The second light source 4 emits green point light, which enters the probe 2 along the axial direction of the probe 2 after being reflected by the half mirror 18, and reaches the left end surface of the probe 2, and the resulting image can be received by the image sensor 5 and displayed on the display 9 , when the probe 2 is not in contact with the eyeball, the image sensor 5 detects the reflection from the left end of the probe 2, forming a circular image; when the probe 2 is almost in contact with the cornea, the image sensor 5 detects the reflection from the surface of the eyeball, forming a circular image Another circular image, when the probe 2 is almost in contact with the cornea, if the incident green light is reflected by the cornea and the left end of the probe 2, if the two circular images overlap, that is, only one circular image appears on the monitor 9, indicating the coaxial situation Reached, if a deviation of the two circular images occurs, coaxiality is not achieved. All of these can be displayed on the display 9 to facilitate the operator's observation. Through this display window, it is more convenient to judge whether it is coaxial. At the same time, the visible green dot light exits through the left end of the probe 2, which can also help the operator find the probe 2 and the cornea more quickly with the guidance of this light. contact position.

As shown in FIG. 6 , the strain gauge 6 , the image sensor 5 and the display memory 10 are all connected to the microprocessor 7 . Display memory 10 , display 9 , microprocessor 7 , first light source 3 , second light source 4 , strain gauge 6 , image sensor 5 , and speaker 19 are all connected to power supply 8 . The horn 19 is fixedly installed in the casing 1 , and the horn 19 is connected with the microprocessor 7 . The microprocessor 7 is responsible for monitoring and calculating all the data provided by the image sensor 5 and the strain gauges 6 . The display memory 10 is connected with the microprocessor 7 to display and store the intraocular pressure value obtained through processing and calculation. The intraocular pressure value is the value obtained by dividing the applanation force by the corresponding applanation area.

The operating principle of the portable tonometer of the present invention is:

When the probe 2 is not in contact with the eyeball 20, the left end face of the probe 2 seen at the receiving window 15 of the image sensor is bright, that is, the image detected by the image sensor 5 is a white image, because the first light source 3 is vertical The incident light is refracted on the side and left end of the probe 2, enters the air, and forms a diffuse reflection outside the probe 2. Part of the light enters the probe from the left end of the probe 2 together with ambient light. After the light passes through the probe 2, it enters the probe. into the image sensor 5, therefore, what the image sensor detects is a white image. However, when the probe 2 is in contact with the cornea of the eyeball 20, when the light is incident on the probe 2, the vertically incident light is refracted on the inner surface of the corresponding side, and irradiates the eyeball 20 together with the light refracted from the left end surface of the probe 2. In the contact surface part, most of the light rays are all incident into the eyeball 20, forming an impression between the probe 2 and the cornea of the eyeball 20, and the image sensor 5 detects a dark circular image 17, as shown in FIG. 2 In the non-contact part of the left end surface and the eyeball 20, the light refracted by the side surface of the probe 2 and the bottom surface of the probe 2 will enter the probe 2 again after being partially reflected by the eye wall, and then focus on the receiving window 15 of the image sensor 5 through the convex lens 16, which corresponds to The bright part 21 in the image detected by the image sensor 5 is refracted from the probe 2 and reflected or reflected multiple times, and the light entering the probe 2 again can also illuminate the contact edge of the probe 2 and the cornea of the eyeball 20 The tear ring 22, so that the image 23 formed by the tear ring 22 can be effectively distinguished from the dark circular image 17 produced by the real indentation, and the image sensor 5 only recognizes the dark circular image 17, thereby improving the accuracy of measurement and providing accurate measurement Intraocular pressure provides a reliable technical approach. The ambient light 24 can better help to eliminate the influence of tear fluid on detecting the dark circular image 17 to be detected. The image sensor 5 is focused on the center of the left end surface of the probe 2 to facilitate receiving the dark circular image 17 generated from the indentation. 5 a , 5 b , and 5 c show cross-sectional views of the left end face of the probe 2 seen at the right end face of the probe 2 , that is, images detected by the image sensor 5 . When the light emitted by the first light source 3 enters the probe, it will be refracted on the inner side wall and the left end surface of the probe 2. When the center of the left end surface of the probe 2 starts to contact the eyeball 20, the contact part is a dark circular image 17, which is collected by the image sensor 5. The image data is transmitted to the microprocessor 7 at the same time. As the pressure increases, the diameter of the dark circular image 17 will gradually increase, and the image sensor will continuously collect and transmit data. Figures 5a, 5b and 5c respectively show the corresponding images generated at the left end face of the probe 2 viewed from the position of the image sensor 5 as the pressure increases. At the same time, the corresponding applanation force collected by the strain gauge 6 is also continuously transmitted to the microprocessor 7 , and the intraocular pressure value is given after being processed by the microprocessor 7 .

When the portable tonometer of the present invention is in use, proceed according to the following steps:

The first step: press power switch 25, provide corresponding voltage to each part, by means of the green light beam that the second light source 4 sends in the device of the present invention, the probe 2 is aimed at the top of the dome cornea on the pupil of the subject, according to For the image in the display 9, fine-tune the vertical direction of the probe 2, so that the probe 2 and the eyeball 20 are all on the same straight line, which is convenient for accurate measurement of intraocular pressure;

Step 2: The operator slowly touches the probe 2 vertically to the cornea. At this time, the image sensor 5 collects the data that meets the requirements and transmits it to the microprocessor 7. At the same time, the microprocessor 7 issues instructions, and the corresponding pressure data is collected. In the process of pressing down, the device will continuously collect qualified data. During this process, the intraocular pressure results corresponding to each set of data will be displayed on the display memory 10 and temporarily stored by its storage system.

Step 3: The microprocessor 7 calculates the corresponding intraocular pressure value, and simultaneously records and displays the applanation area, applanation force, and intraocular pressure in the whole process of measurement in real time.

For medical clinical use, 5 groups of data required for collection can be set, and the voice speaker 19 prompts that the collection is completed. After five times of results meeting the requirements are collected, the average is calculated, and finally stored and displayed.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (5)

1. A portable tonometer, characterized in that: comprising a housing (1), a probe (2), a first light source (3), an image sensor (5), a strain gauge (6), a microprocessor (7) , power supply (8) and display memory (10), the far-end face of described probe (2) is circular, is made of transparent optical material, and the proximal end of described probe (2) is fixedly installed with at least two elastic beams ( 12), each elastic beam (12) is perpendicular to the axis of the probe (2), and the outer end of each elastic beam (12) is fixedly connected to the far end of the housing (1), and the elastic beam ( 12) A strain gauge (6) is installed on it, and the first light source (3), image sensor (5), microprocessor (7), power supply (8) and display memory (10) are all installed in the casing (1 ), the image sensor (5) is located at the proximal side of the probe (2), the axis of the receiving window (15) of the image sensor (5) coincides with the axis of the probe (2), and the image sensor (5) The diameter of the receiving window (15) is equal to or smaller than the diameter of the distal end face of the probe (2), the first light source (3) is arranged around the receiving window (15), the microprocessor (7), display memory ( 10), the strain gauge (6), the image sensor (5) and the first light source (3) are all connected to the power supply (8), and the strain gauge (6), the image sensor (5) and the display memory (10) are all connected to the display memory (10) Microprocessor (7) is connected, The far end side of the receiving window (15) of the image sensor (5) is provided with a convex lens (16), the central axis of the convex lens (16) coincides with the axis of the probe (2), The near-end fixing sleeve of the probe (2) is equipped with an annular carrier (11), and the inner end of each elastic beam (12) is fixedly installed on the probe (2) through the carrier (11), and the housing ( The far end of 1) is provided with at least two support beams (13), and the support beams (13) are parallel to the elastic beams (12), and each support beam (13) is located at the far end side of the elastic beams (12), An adjustment screw (14) for adjusting the distance between the support beam (13) and the carrier (11) is installed at the inner end of the support beam (13). 2. The portable tonometer according to claim 1, characterized in that: the first light source (3) is in the shape of a ring and is set on the receiving window (15) of the image sensor (5). 3. The portable tonometer according to claim 2, characterized in that: the probe (2) is made of glass or resin. 4. The portable tonometer according to claim 3, characterized in that: it also includes a horn (19), the horn (19) is fixedly installed in the housing (1), and the horn (19) communicates with the microprocessor ( 7) Connect. 5. Portable tonometer according to claim 4, is characterized in that: also comprise second light source (4), display (9) and half mirror (18), described display (9) and half mirror ( 18) fixedly installed in the housing (1), the half mirror (18) is positioned at the far end side of the convex lens (16), the axis of the probe (2) passes through the half mirror (18), the half mirror The axis of the mirror (18) forms an included angle of 45 degrees with the axis of the probe (2), and the second light source (4) is positioned directly above or directly below the half mirror (18), and the second light source (4) is As a point light source, the light emitted by the second light source (4) is reflected by the half mirror (18), and is incident on the center of the far end surface of the probe (2), and the image sensor (5) is connected with the display (9).