Contact-type applanation tonometer calibrating apparatus and method

Abstract

The invention relates to a contact-type applanation tonometer calibrating apparatus and method, and belongs to the field of tonometer detection. The contact-type applanation tonometer calibrating apparatus comprises a horizontal base, an electronic scale, a three-dimensional adjusting base and an L-shaped balance support; a fixing column and a horizontal installation table are arranged at the positions, close to the left edge and the right edge of the horizontal base, of the horizontal base respectively, the electronic scale is placed on the horizontal installation table, and the L-shaped balance support is placed on the fixing column and the electronic scale in a stretching-across mode; a door-shaped supporting table stretches across a horizontal rod of the L-shaped balance support, and the three-dimensional adjusting base is placed on the door-shaped supporting table. The L-shaped balance support is liner contact with the fixing column and is in point contact with the electronic scale, and a tonometer is calibrated according to the moment balance principle. By means of the contact-type applanation tonometer calibrating apparatus and method, the calibrating accuracy stage is high, and the good long-term stability and the good repeatability are achieved.

Description

technical field [0001] The invention belongs to the field of tonometer detection, in particular to a verification device and method for a contact applanation tonometer. Background technique [0002] The pressure inside the eyeball is called intraocular pressure, or intraocular pressure for short. Intraocular pressure is one of the important means and indicators for diagnosing ophthalmic diseases, observing the condition, estimating the prognosis, evaluating the curative effect, etc., especially for judging clinical ocular hypertension, normal tension glaucoma and primary open-angle glaucoma An important basis for ophthalmic diseases. [0003] At present, tonometers can be roughly divided into three categories: indentation tonometers, applanation tonometers, and non-contact tonometers. The applanation tonometer represented by Goldmann is currently the most accurate tonometer recognized internationally. It is based on the Imbert-Fick principle: P (intraocular pressure) = W (...

AI Technical Summary

Problems solved by technology

[0004] ISO 8612-2009 international standard: the cross balance mechanism in the form of a balance knife such as figure 1 As shown, it is difficult to control the initial balance. Even if the material density of the balance bar is uniform and completely symmetrical, although the torque generated by gravity on both sides is theoretically equal, this is an unstable balance and will be stable in the form of "X".

Secondly, the basis for judging the balance in the international standard is the coincidence of the scale lines on the right side. When it is difficult to achieve a complete static balance, it will cause certain difficulties to carry out the verification work, and the efficiency is relatively low. In the case of long-term high pressure As a result, the sharpness of the knife edge decreases, and the knife edge and the plane change from the original line contact to the surface contact, resulting in a decrease in the discrimination of the device and causing errors, thus affecting the long-term stability and repeatability of the device

[0005] However, the verification device of domestic contact applanation tonometer is only available in the Chinese Academy of Metrology, but the device detection method is simplified on the basis of the ISO 8612-2009 international standard, and the measuring head is used in the measurement of the pressure error. The method of directly contacting the force sensor to read the force value will cause the accuracy of its measurement results to directly depend on the accuracy of the force sensor, and more importantly, the long-term stability of the force sensor will directly lead to a decrease in the measurement repeatability of the device. There are certain problems, and the international pressure error measurement is traced to the mass of the standard weight and the force arm of the balance bracket, while the current method adopted by the China Institute of Metrology is directly traced to the indication value of the force sensor, which will lead to The verification device of the domestic contact applanation tonometer cannot meet the international testing level technically, and it is difficult to compare with the international device level in the method

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