FI109269B - Method and apparatus for measurement of eye pressure - Google Patents

Description

, 109269

Apparatus for measuring intraocular pressure

The invention relates to a device for measuring intraocular pressure. Device basic 5 brings the song to the eye to understand the laws of collision.

In general, intraocular pressure is measured by tonometers placed on the surface of the cornea of the eye and its elasticity is measured by various methods (Goldmann tonometer, Schiötz tonometer, etc.). The two most commonly used principles in these 10 measurements are measuring the force required to flatten a particular area of the eye or measuring the diameter of a region that a given force flattens.

These methods require patient collaboration and are not suitable without general anesthesia for young children, dementia or animals.

Methods have also been developed which do not touch the surface of the cornea but measure the intraocular pressure using a water or air jet or various waves, e.g., U.S. Patent Nos. 5,148,807, 5,279,300, and 5,299,573. require sophisticated technology and are therefore expensive. By air jet ·; ·. There are many optometrists that work, but the price has been es- • · ·. 20 for wider use as a general practitioner tool.

It is also known, in U.S. Patent No. 5,276,139, a method wherein a free: T: a falling ball is dropped on the eyelid and the height of bounce of the ball is measured.

• 7 ·! It is an object of the present invention to provide a simple, inexpensive and accurate * · device capable of measuring intraocular pressure also in non-cooperative patients, which can only be kept in the field for a moment. In addition, the meter is suitable for extensive screening,. · · ·. since the measurement is quick without local anesthesia and does not require special trained staff. Another goal is to organize a home follow-up for ophthalmic patients.

The foregoing and other advantages and advantages of the present invention are achieved by the method and apparatus of the invention, the features of which are disclosed in the appended claims.

The invention will be described below. The probe is brought to a specific, metered, or otherwise sufficiently accurate range of motion. When the probe-5 collides with the eye or closed eyelid, the motion state of the probe changes. According to the invention, the continuous motion of the probe is measured in a suitable manner, for example by utilizing an exemplary device according to the invention, and on the basis thereof intraocular pressure is applied. Thus, a complete motion analysis is performed on the collision and thereafter, including the effect of gravity and friction on the body. Thus, the analysis carried out will comprehensively monitor the motion and derive intraocular pressure according to the laws of physics known per se.

The probe and its sensors are light and the speeds used are low and there is no risk of eye damage. The method can also be applied while the eyelid is closed. Due to the low speed of the probe used and the low mass, the eye does not need to be anesthetized under any measurement conditions. If necessary, the meter shall be calibrated by different standards, comparing the results with other methods. or by using experimental methods.

«•. The device according to the invention contains few parts. The device can be shaped into a small, easy-to-handle unit. The operation is simple and does not entail high costs. The invention provides a better accuracy for this device than before, and it is also possible to take into account both random changes as well as variables that change over time, such as device friction.

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•; In the following, the invention will be described in detail with reference to the drawings in which * * »: Figure 1a schematically shows a side view of the device according to the invention in many simplified ways, at baseline;

Figure 1b shows a pattern similar to Figure 1 in which the probe transmission to the eye required for measurement has been performed; 109269 3

Figures 2a-2c show, in practical experiments, velocity curves obtained by the apparatus operating on the principle shown in Fig. 1, at an eye pressure of 5, 20 and 60 mm Hg respectively, and Fig. 3a shows a side view of an embodiment of the invention;

Figure 3b is a more detailed view of the detail of the device of Figure 3a.

Figure 1a thus shows a simplified view of the device for measuring intraocular pressure according to the invention in many ways. For example, the housing of the equipment in which the parts are located is completely omitted from the drawings. The pattern has also been simplified.

Thus, meter 1 comprises only a few basic components and is thus very simple. The device according to the invention includes a coil 2 of the solenoid type. The coil 2 is connected, in a manner known per se, with power cords 3, 4, a power supply 5 and a circuit switch 6 for closing and opening the circuit. The device also has a second coil 7, which also has conductors 8, 9 and a meter 10. The coil 7 may be mechanically wound to the same structure. They may even; uses the same coil as coil 2 and coil 7, with wires 3 and 8 and 4 and 9 respectively connected to the same coil terminal.

The device includes a nonstandard magnetized counterpiece inside or at the end of the coil 2: · 25 lugs 25 for attaching the permanent magnet 12. The housing of the device, not shown here, has a bearing shaft 11 with a permanently magnetized part 12 at its end.

•; · At start, part 12 is magnetically secured to the stop member 25 inside or at the end of the reel 2. Electrical connections and direction of the magnet 12 and coil 2. ·: ·. nat is arranged so that when switch 6 closes and circuit coil 2 at the same time * I ·. ·. As 30 closes, the coil 2 causes the magnet 12 to be pushed, which causes the magnet 12 and the arm 11 to move away from the coil 2.

A probe 13 is connected to the arm 11 and, as described above, the probe 13 follows the arm 11 and is ejected outwardly from the device and thus toward the eye 14. The probe may be of any suitable type, for example an elongated replaceable part with a suitable blunt, clean On the other hand, the arm 11 itself can act as a probe in the sense described above, and thus the arm 11 will continue to be continuous from the end containing the magnet 12. The operation of the tip and part 5 will be described later.

Figure 1b shows that with the movement caused by the coil 2, the magnet 12 moves within the coil 7 and in a known manner causes a voltage on the coil, measured as a signal through the wires 8, 9 at meter 10. The magnitude of This is a reliable and accurate way to measure speed.

Figures 2a-2c show three exemplary cases of the velocity curves obtained under experimental conditions by pressurizing the pig's eye to 5, 20 and 15, respectively, 60 mm Hg. As the graphs clearly show, the velocity changes clearly in different ways when talking about pressurized eyes at different pressures. The speed (or signal strength) is shown on the vertical axis. The horizontal axis, on the other hand, represents the time in milliseconds.

Fig. 3a shows an embodiment of the device according to the invention, including in this case also a housing 15 which is of size and shape in the hand; '. suitable and containing the above components, in addition to the circuit board 16 and the display 17. The electronics take care of the speed values obtained to convert them to the pressure values of the display 17, in units of mm Hg or other suitable: '| 25 pressure value. The device is powered by a battery 24 located inside the housing 15. Most preferably, the power supply 24 is a small rechargeable battery.

: '': The operating switch 6 is here a finger pressed knob used to reel 2: ·. the given current pulse is always the same length and its voltage / current values are for each. . : 30 Sat the same time. Electronic components commonly used for this type of application are used to confirm this.

Fig. 3a and, to a larger extent, Fig. 3b show a part which has many functions and which is particularly simplistic in operation and simple in principle. This part is integrally formed by a tubular part 22, which is connected in a suitable manner to the housing 15, for example by a lock ring, and has bearings for moving the shaft 11 in a linear and precise manner. An elongated sleeve-like portion 18 is disposed over the tubular portion 22 such that a spring 21 is provided between the flange-like front 23 of the portion 22 and the rear of the sleeve 18.

| The front portion of the sleeve 18 is closed by an ejector member 19, which may be, for example, a hole plate or the like, through which the shaft 11 is suitable to pass.

The baseline measurement is shown in Figure 3a. At the end of the shaft 11 a clean, for example disposable tip portion 20 is disposed, such that the shaft 11 and the tip portion 20 at its end are toward the eye to be measured. Pressing the trigger 6 causes the shaft 11 with its tips 20 to move towards and hit the eye, and to bounce back in a manner dependent on the pressure of the eye. The electronics constantly take care of measuring speed and converting the values obtained into 15 visible formats on the display 17.

Once the measurement has been made, the sleeve or cover part 18 is pulled away from the housing 15 of the device against the force of the spring 21, whereby the ejector part: ·. 19 causes the tip portion 20 to disengage and fly away as shown in Figure 20 3b. Spring 21 resets sleeve 18 to its original position. A new clean tip section is then placed on the shaft 11 for the next measurement. The shaft 11 returns to its starting position, for example, by simply turning the gauge T to a position where part 18 is up. In this case, the shaft 11 with its magnets is returned by gravity to a position where the magnet 12 is locked in response to the · ·, · · · 25 in the piece 25 where it remains attached due to the pulling force of the magnet 12. This' ... always ensures the same and comparable baseline.

: '' ': In the case where a separate probe part 13 is attached to the shaft 11, a spacer, · ·. This connection may be based, for example, on friction between the parts, but the probe may also be: 30 also rotatable.

The portion 18 may be used, via an optional attachment thereto, to support the meter at a desired distance from the subject's eye, thereby providing further comparability between the various measurements.

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The invention enables many modifications not described above.

Thus, instead of the coil 2, the spring 11 actuator can also be used as the driving force for the arm 11.

As stated above, the device according to the invention is extremely inexpensive, simple and reliable. Even at the manufacturing stage of the device, no expensive mold technology is required, since the device can be housed in a simple case made for some other purpose, if necessary. All the functions of the device are easy and the principle is so simple and reliable that it requires almost no training.

The invention is not limited to the form set forth in the specification and drawings, but may be modified within the scope of the appended claims.

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Claims (8)

109269 An apparatus for measuring intraocular pressure with a device comprising a probe (11 or 13) supported and housed in a suitable housing (15), a device (2,12) for providing a probe (13) or device (11) in which the probe connected and data processing and display devices (17), characterized in that it comprises means (2, 11, 12) for applying a substantially constant output speed and force to the probe (11, 13) and means (7-10) for moving part ( 11, 12) To register your business space. 10 Apparatus according to Claim 1, characterized in that the means for providing a substantially constant output speed and force consist of a coil (2) and a magnet (12) connected to the shaft (11), whereby the coil (2), when wound, exerts a repulsive force on the magnet. 15 Device according to Claim 1, characterized in that the means for recording the velocity of the moving parts consist of a coil (7) within which the magnet (12) moves and a meter (10) for recording the voltage or current changes caused by the magnet to the coil (7). 20 Device according to one of Claims 1 to 3, characterized in that it comprises means for a pulse of a substantially constant size and duration:. to the probe. Device according to one of Claims 1 to 4, characterized in that: *: a coil (2) is provided with a stop piece (25) to which the magnet (12) is magnetically attached: * for holding the shaft and the magnet and securing the starting point. I 1 t (I 1 Device according to Claim 1, characterized in that the shaft (11) of the magnet (12) is supported by a separate sleeve-like part (22) which is: ": possibly detachable from the housing (15)." > I 109269 Device according to Claim 1 or 6, characterized in that a portion (18) movable linearly against the force of the spring (21) is attached to the part (22) and is provided at its outer end with a displaceable part (19) located at the shaft end. for detaching the tip (20) from the shaft (11) by said 5 movements. Device according to claim 1, characterized in that the coils (2) and (7) are structurally the same or that the coils (2) and (7) consist of only one coil which performs both of these functions. 10 t I * t I T09269 g