PRESSURE MEASUREMENT METHOD USING NONLINEAR VIBRATION OF VISCOELASTIC MATERIAL

Abstract

Glaucoma is a disease that can cause blindness, and various causes have been pointed out, but it is generally known that the optic nerve is pressed by high intraocular pressure (IOP) to cause it. Accurate and simple measurement of IOP is essential because medical staff can periodically measure IOP throughout the day and thereby prevent glaucoma. The conventional method of measuring IOP is mainly used because the method of directly contacting the eyeball and measuring it has high accuracy. However, this measurement method requires the use of experts and makes it difficult for patients to use it in the form of direct contact with the eyeball, so a method and equipment to improve it are needed. The eyeball is a structure made of viscoelastic material and containing body fluid inside. Therefore, in order to measure the internal pressure of the fluid surrounded by a viscoelastic material similar to the eyeball on the eyelid, a device of a method of applying and measuring vibration was devised. When a device is brought into contact with a viscoelastic material and vibration is applied while changing the excitation force, the amplitude and attenuation of the response are measured differently according to the characteristics of the viscoelastic material. Since this vibration response changes according to the nonlinearity of the viscoelastic material and the pressure of the fluid, the pressure of the fluid can be determined by measuring the vibration. In order to show the validity of the proposed method, nonlinear vibration response analysis was used and compared with actual experimental results.