Research On Jet Pressure Control Technology Of Non-contact Ophthalmometer

Intraocular pressure(IOP)is an important parameter to determine glaucoma in the medical field.The accurate detection of IOP is directly related to the early diagnosis of glaucoma.For this reason,more and more countries are studying the detection technology of intraocular pressure.At present,most of the contact detection methods are used at home and abroad.This method needs to contact the cornea,which is easy to cause corneal cross infection and damage,so non-contact detection has become a trend.The most remarkable feature of non-contact intraocular pressure detection technology is to use air jet instead of mechanical pressure bar.Air jet control is the key technology link that affects the accuracy,comfort,stability and efficiency of detection.Therefore,the research of air jet control technology in the field of non-contact intraocular pressure detection technology is a key research direction.In order to improve the measurement accuracy and the comfort of patients,this paper proposes a new jet pressure control technology to detect intraocular pressure,which can reduce the deformation of cornea by controlling the output size of pulse air pressure,and then get the pressure of cornea based on the principle of force balance.Firstly,considering the influence of the initial position of the piston on the detection,three initial positions of the piston are studied to realize the coarse adjustment of the jet pressure and capacity;secondly,in order to adjust the jet pressure precisely and adaptively,a PID control algorithm based on BP neural network is designed to control the jet pressure in real time when the jet pressure is greater than the set pressure;secondly,according to the system The main hardware circuit and control software are designed in the overall research scheme;finally,the flattening signal and pressure signal are tested,and the final test prototype is established to complete the measurement experiment of the simulated eye.The experimental results show that the control technology designed in this paper can adjust the pressure,the error of jet pressure is within ± 0.5KPa,and the error of intraocular pressure value detected by intraocular pressure is within ± 1.5mm Hg,which meets the expected control technical requirements.