RU2318429C2 - Method and device for determining intraocular pressure through eyelid - Google Patents

Abstract

FIELD: medicine; medical engineering.

SUBSTANCE: method involves studying static deformation of eyelid under bearing member load. One of probes is used as the bearing member. The probes receive mechanical load from external force source and transmit pressure to eye. The pressure is variable in time and different in each probe. Intraocular pressure is determined with pressure sensors at the moments the relative displacements of the probes varies due to eye deformations taking place.

EFFECT: high accuracy of measurements through eyelid irrespective of geometrical and physical properties of eye.

3 cl, 3 dwg

Description

The invention relates to the measurement of physical quantities and can be used to measure intraocular, intracranial and other pressure.

A known method for determining intraocular pressure Maklakov, based on the installation on the human eye of a certain load with a flat surface. By the area of contact of the cargo with the surface of the eye (the size of the punching) determine the value of intraocular pressure / 1 /.

When using this method, it is necessary to use local anesthesia. The accuracy of the method is affected by the radius of curvature of the cornea of the eye, and in 10% of people it differs from the average value.

Closest to the proposed solution is a method for determining intraocular pressure through the eyelid, which works as follows. A device is placed on the human eyelid, pressed to the eye, then a rod of a certain weight (stock) falls onto the eye through the eyelid, which penetrates into the depth of the eye by a certain amount and bounces. According to the spatio-temporal parameters of the penetration of the rod deep into the eye, intraocular pressure is determined / 2 /. The amount of movement of the rod determines the displacement sensor.

When using this method, the accuracy of the result is exerted by the final rate of fall of the rod, which is determined by the thickness of the eyelid, the friction of the rod against the body of the device and the speed sensor, the external temperature, and the tilt of the device relative to the vertical position. The accuracy of the measurement result is also affected by the radius of curvature of the eye and the perpendicularity of the axis of the fall of the stem to the surface of the eyes, the reaction (twitching) of the eye to the stroke of the stem and the damping of the shock by the muscles holding the eyeball.

The problem to which the invention is directed is to create such a method for measuring intraocular pressure through the eyelid, in which the measurement result does not depend on the conditions of the fall of the stem, the radius of curvature of the cornea of the eye, and the accuracy of installation of the device on the surface of the eyelid.

The technical result is aimed at creating a device that allows you to determine intraocular pressure through the eyelid, regardless of the geometric and physical characteristics of the eye and the eyelid covering it, twitching of the eye, muscle reaction, various vibrations and the accuracy of installation of the device on the eye.

In the proposed method and device, the technical result is achieved by using at least two probes in the form of rods mounted on the eyelid, which is tightly pressed to the eye. Using the probes, pressure is applied to the eye so that the pressure of the probes on the eye is different and variable in time, while pressure and displacement sensors are installed on the probes.

The analysis of the prior art, including a search by patents and scientific and technical sources of information containing information about analogues of the claimed invention, allows us to establish that the applicant has not found technical solutions characterized by features identical to all existing features of the claimed invention. The difference from the list of identified analogues of the prototype made it possible to identify a set of essential (with respect to the technical result perceived by the applicant) distinctive features in the claimed object set forth in the claims.

Therefore, the claimed invention meets the requirement of "novelty" under the current law.

Information about the fame of the distinguishing features in the totality of the characteristics of the known technical solutions with the achievement of the same as the claimed device has no positive effect. Based on this, it was concluded that the proposed technical solution meets the criterion of "inventive step".

A method for measuring intraocular pressure and a device for its implementation is illustrated in figures 1-3.

Figure 1 presents a method for determining intraocular pressure.

Figure 2 presents the location of the four probes on the eyelid.

Figure 3 presents a device for determining intraocular pressure.

The method for determining intraocular pressure works as follows (figure 1), on the eyelid 2, pressed against the eye 1, two probes (rod) 3 and 4 are installed, on which pressure sensors 7 and 8 are installed, and displacement sensors 9 and 10 relative to the housing 11 Further, mechanical probes 5 and 6 are applied to the probes 3 and 4 along their axis (perpendicular to the surface of the eye). The pressure exerted by the probes 3 and 4 on the eyelid 2 and the eye 1 is proportional to the force of action 5 and 6. It is necessary that the pressure of the probe 3 and probe pressure 4 on the eye differed by a certain value y, while the pressure change should occur in the range to be measured pressure. For the human eye, this value is in the range of 5-60 mm Hg. Moreover, if the pressure of the probes on the eye is less than the intraocular pressure, then they do not deform the surface of the eye. If the probe with high pressure starts to deform the eye, determined by the displacement sensor, but the probe with less pressure is not, then at this moment the intraocular pressure is determined by the pressure sensor. If the probe with less pressure also begins to deform the eye, determined by the displacement sensor, then at this moment the intraocular pressure is also determined by its pressure sensor. The pressure of the internal structures of the eyelid of the eye is much less than the intraocular pressure, therefore, by moving the probes during the forcing of the eyelid with a pressure of more than 15 mm Hg can be neglected. In this case, the probe, which performs less pressure, can be called a reference, and the probe, which carries more pressure, is an element of deformation.

The need to use two probes is determined by the possibility of accidental movement of the eye along the axis of influence of the probes. In this case, both probes are moved parallel to each other by the same amount, and pressure measurement does not occur. When measuring pressure, it is necessary to fix a person’s gaze in one direction, then two probes are enough, but if the eye rotates left-right and up-down, the radius of curvature of the surface and the mutual movement of the probes and, therefore, an erroneous pressure measurement can change. To prevent such a measurement error, it is advisable to use more than two probes on an independent suspension. Figure 2 shows a method in which four probes are used, three of which 3, 3 'and 3 "create approximately the same pressure on eye 1 and are located at the corners of an equilateral triangle, and the fourth probe provides 4 pressure on the eye noticeably different from the other three probes, for example 2 mm Hg larger, and are located at an equal distance from the other three probes (in the center of an equilateral triangle). Such use of four probes will always allow accurate pressure measurement regardless of movement and rotation as for and measuring device. The authors do not deny the use of two probes for measuring intraocular pressure while fixing the direction of human eyes in one direction.

Figure 3 shows a device for measuring intraocular pressure, consisting of a central probe 4, which is mechanically connected to a pressure sensor 8, a displacement sensor relative to the second probe 10, an additional pressure unit 6, while the device includes a second bifurcated probe with contact pads 3 and 3 ', which is mechanically connected to the pressure sensor 7, a displacement sensor relative to the body of the device 9. In this case, the second probe 3 can be called a support, and the probe 4 is a deformation element.

A device for measuring intraocular pressure works as follows: two probes 3 and 4 are installed simultaneously on the eye 1 through the eyelid 2, while the probe 3 is bifurcated and installed on the eye with platforms 3 and 3 ', and the probe 4 is located in the same plane with the contact pads 3 and 3 'and is located between them in the center of the probe 3. Next, a force-increasing pressure is applied by a finger of a person 12, measuring pressure on the damper 5, which softens the vibration of the hand and transfers pressure to the probe body 3 and the additional pressure unit 6, while being fixed I using pressure sensors 7 and 8, the pressure of the rods on the eye, simultaneously measuring the movement of the probe 3 relative to the housing 11 using the displacement sensor 9 and moving the probe 4 relative to 3 using the displacement sensor 10. Measurement of the intraocular pressure occurs when the probe 4 begins to deform the surface of the eye, i.e. the probe 4 will move relative to the probe 3. As dampers, calibrated springs can be used.

It is advisable to use more than two probes in the device for measuring intraocular pressure in order to increase the accuracy of measurement. For example, when using three probes with independent pressure on the eye, it is necessary to install out of the same line (in the same plane). In this case, the damper 5 must evenly distribute the pressure to the two extreme probes, and the additional pressure unit 6 is connected to the central probe. And, for example, when using four independent probes, the damper 5 must evenly distribute the pressure on the three probes 3, 3 'and 3 ", figure 2, and the pressure unit 6 is connected to the central probe. In this case, the probes creating the same pressure on the eye 1 are located at the corners of an equilateral triangle, and the fourth deformation probe 4 exerts greater pressure on the eye and is located at an equal distance from other probes (in the center of the triangle) and is connected by a displacement sensor to one of the reference probes and is also equipped with a pressure sensor.

Information sources

1. Big Medical Encyclopedia, 3rd ed., Moscow, 1980, - Volume 13, p. 363.

2. RF patent No. 98101607, 1999. A method for measuring intraocular pressure through the eyelid and a device for its implementation. Pilecki G.K., Ivanishchev K.V. and etc.

Claims (3)

1. A method of measuring intraocular pressure through the eyelid, based on the static deformation of the eyelid by the support load, characterized in that at least two probes with pressure sensors for eye and displacement relative to the body are used, one of the probes being used as a support, in the measurement process on the probes is carried out with a time-varying and different relative to each other mechanical pressure on the eye supplied to the probes from an external source of force, while the intraocular pressure is determined using pressure sensors in cients change of mutual displacement during deformation probes eye. 2. The method of measuring intraocular pressure through the eyelid according to claim 1, characterized in that the probe used in the form of a support consists of two identical probes, between which another probe is located in the center. 3. The method for measuring intraocular pressure through the eyelid according to claim 1, characterized in that the probe used in the form of a support consists of three identical probes, which are located on the eye at the vertices of an equilateral triangle, and the other probe is located at an equal distance from the other three probes - in the center of the resulting equilateral triangle.

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