Device and method for non-contact intraocular pressure measurement based on coaxial principle

Abstract

The invention relates to a device and a method for non-contact intraocular pressure measurement based on a coaxial principle. A front end wall of a device box and the internal of a box are respectively embedded with a first convex lens and a second convex lens. The central position of the first convex lens is provided with an airflow hole along a main axis of the first convex lens. The top end ofbox is provided with a parallel light emission device arranged vertically downward. The middle part of the box is provided with a semi-transparent semi-reflecting lens corresponding to a photoelectronemission device, the semi-transparent semi-reflecting lens is mounted in an inclination angle of 45 DEG. The rear end portion of the box is provided with a light intensity detection device. The box is provided with a gas inlet connected with a compression gas pipeline. The compression gas pipeline is provided with an electromagnetic proportional valve. The device realize a sphere plane pressing center, an airflow injection orifice center, a lens center, a light intensity detection device center to be coaxial, so as to reduce error deviation of light and improve sensitivity and accuracy of measurement.

Description

technical field [0001] The invention belongs to the field of intraocular pressure measurement and medical electronic instruments, in particular to a non-contact intraocular pressure measurement device and method based on the coaxial principle. Background technique [0002] Intraocular pressure is the pressure inside the eyeball, specifically the equalized pressure exerted by the contents of the eye on the wall of the eyeball. The intraocular pressure of normal people is stabilized within a certain range to maintain the normal shape of the eyeball and ensure the maximum optical performance of the refractive medium. Common intraocular pressure measurement is divided into finger pressure method, liquid manometer method and tonometer method. In order to accurately measure intraocular pressure, clinical diagnosis mostly uses tonometer measurement, which can be divided into contact measurement and non-contact measurement. There are two main types of contact measurements, corneal...

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Problems solved by technology

[0003] At present, there are relatively mature researches on non-contact measurement in foreign countries, and the representative instruments are mainly divided into two categories: the first type is laser interferometric tonometer, the principle is to vibrate the cornea through sound waves or airflow, and use the vibration amplitude and The ratio of intraocular pressure to measure intraocular pressure is complex in structure and expensive

The second type is the non-contact gas injection tonometer. The principle of this instrument is that the system injects air to the top of the cornea, and the intraocular pressure value is measured by the same internal and external pressure at the moment of applanation. The measurement is rapid and the operation is simple. The systems are independent and not coaxial, the measurement system is complicated and the measurement reliability of the high intraocular pressure area is low

However, domestic clinical tonometers are all imported from abroad. In response to this situation, some researchers have adopted non-contact measurement technology based on the principle of pressure balance, and designed a symmetrical structure to measure the instantaneous pressure of the airflow to the eyeball by using the reaction force of the jet airflow. Photoelectricity is used as a corneal applanation detection system, and the accuracy is guaranteed, but the overall structure is still complicated, and the detection system uses infrared light to illuminate the side, and there are errors caused by the convex characteristics of the eyeball surface

It is difficult to control the symmetry of the dual air flow nozzles used in the air injection device, which is easy to cause measurement errors

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