SU363476A1 - ALL-UNION - Google Patents

Description

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The invention relates to medical technology, namely to vacuum eye tonometers.

Eye vacuum tonometers are known which are provided with a capsule containing a hollow cylinder attached to a cornea.

Their disadvantage is that they do not allow determining intraocular pressure directly in millimeters of mercury and require very complex calibration.

The proposed eye vacuum tonometer, in which this drawback is eliminated, differs from the known ones in that its cylinder is provided with a powder that creates a permanent unplantation of the eye:

FIG. 1 schematically shows the proposed eye vacuum tonometer, side view, front and bottom; in fig. 2 - the same. the section along the A-A in FIG. one.

The proposed vacuum eye tonometer contains a capsule, the body of which has an expanded hollow cylindrical part /, a working cylinder 2 and a conical part 3. The free edge of the cylindrical part is sucked to the cornea surface of the eye being examined.

The capsule capsule has a flat, applanning portion 4, a bottom 5 and a guide rod 6 passing through the opening 7 in the conical part 3 of the capsule body. The area of the piston's approximate surface, for example, twice the cross-sectional area of the working cylinder 2. A through channel 8 passes through all parts of the piston. On the applaning surface of the chamber, this channel passes into the groove 9, reaching the very edge of the piston unit.

The bottom of the box slides freely within the working cylinder 2 capsules; its movement downwards is limited by the nut 10, screwing the end of the rod on the rod, and upwardly the collar 11 on the rod of the shaft. On the nut 10 is a tension rubber tube 12, which serves to connect the coughs of the tonometer with the device that creates the wykum. With the aid of the strip 13, this rubber tube is fixed to the metal tube (4), which is soldered to the capsule body. Below the strip 13, the rubber tube has an arcuate bend, the end of which is pulled over the nut 10, which is screwed onto the core of the core. This arc-shaped bending is not obtained due to the bending of the straight tube, but as a result of imparting this shape to the tube during the vulcanization process.

The rubber tube 12 due to bending and due to the attachment to the metal tube higher than the bend practically does not render

there is no pressure on the bulk of the capsule at

changing the position of the device and the hand of the investigator in the process of tonometry.

A second rubber tube is put on the end 15 of the metal tube 14, the channel of which extends into the cavity of the expanded cylindrical part 1 of the capsule, to connect the bottom of the capsule with a mercury vacuum gauge.

The principle of operation of the eye vacuum applanation tonometer is as follows.

The extended cylindrical part of the tonometer is lowered onto the surface of the cornea of the examined eye so that the free edge of the capsule is located around the concentric limbus. In this case, the piston of the capsule, due to gravity, lowers onto the apex of the cornea, and the opening of the channel 8, located in the center of the approximate surface of the piston, turns out to be closed. Then, using a rubber balloon connected to the capsule by a rubber tube 12, a vacuum is created under the capsule, while air is sucked out of the capsule through a groove 9 cut in the applacating part of the piston until the diameter of the corneal flattening area becomes equal to the diameter of the applanking surface pistons Upon reaching this equality, the entire groove 9 becomes closed with the cornea pressed against it, and further suction of the air is stopped. During the creation of a vacuum under the capsule, air in a certain amount all the time flows under the capsule outside. Through a very thin slit, which is held by a chalk bottom of the piston and the wall of the working cylinder. The presence of this gap is due to the fact that the bottom of the piston slides completely freely in the working cylinder, due to which its friction against the walls of the cylinder is practically eliminated. Thus, the flattened cornea virtually does not fully cover the groove in the aplaning part of the piston, the balance is established automatically by the amount of suction and the amount of air entering the capsule. Thanks to this vacuum applanation

The tonometer not only notes the height of the intraocular pressure at a certain moment, but also provides an opportunity to observe the dynamics of the IOP during the whole examination process.

If nansasyvanna kansuly produced using a vacuum apparatus and apply a mercury vacuum gauge with the appropriate.

To reduce the height of a mercury column on a kimograph drum, then using a vacuum applanacion tonometer, a continuous recording of the level of the ophthalmosis can be made.

At that moment, when the noises of the manometer are set at a certain height, the surface area of the oblate cornea will be equal to the area of the annular piston surface. Since the surface of the piston, pressing on the cornea, is excluded from the scope of the forces of the vacuum, a pressure equal to the difference between the atmospheric pressure and the pressure under the capsule (indicated by the pressure gauge) is exerted on the norn hole only on

This is the area of the bottom of the piston, which does not come into contact with the cornea, and this area is equal to the area of the approximate surface of the piston. In other words, on one and the same planned area of | ogo;

intraocular pressure acts on the side, and external pressure on the outside, the height of which is indicated by the readings of the vacuum gauge plus the weight of the piston. This means that the instructions of the vacuum applanation tonometer indicate the height of the intraocular pressure, with appropriate consideration of the weight of the piston.

Subject invention

An eye vacuum tonometer equipped with a capsule containing a hollow cylinder attached to the cornea, characterized in that, in order to determine the intraocular pressure during constant applantation of the cornea of the eye, the cylinder is provided with a piston.

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