RESEARCH AND DESIGN OF SENSOR FOR GLAUCOMA DIAGNOSIS

Abstract

This paper presents research and design of capacitive co-planar sensor to measure eye pressure (eyeball pressure) for patients with ocular glaucoma (glaucoma).
The sensor structure consists of two thin gold electrodes mounted in a fixed position on a thin silicon plastic sheet, one of which acts as the emitter and the other as the
receiver. Each electrode is divided into 5 rectangular thin foils with a size as small as millimeters. The sensing electrode are fixed on a thin silicon wafer, which has good
elasticity. When pressing the thin silicon sheet with this sensor attached to the patient's eye, the silicon sheet will elastically follow the patient's eye and this changes
the distance of the sensor electrodes leading to a change in the capacitance of the sensor. Thus, the change in capacitance of the sensor will be different depending on
the bulge of the eye (eyeball pressure) of the patient. The proposed sensor can measure ocular pressure up to 24mmHg.
The sensor's operation was investigated by finite element method (FEM) using Ansoft Maxwell simulation software. The simulation results show the change in
capacitance of the sensor when there is a change in eyeball pressure. Based on this simulation result, the size of the sensor's electrodes was found to design the sensor
with the required sensitivity. In this study, the size of the sensor was found with the following parameters: the width of the capacitor electrodes (m = 0.6mm), thickness
of of the capacitor electrodes (n = 0.01mm), distance between capacitor electrodes (k = 0.01mm) and sensor diameter (d = 3.06mm). The sensor can be used in
biomedical and other similar applications.