Design Of The Control System Of Non-Contact Tonometer Based On Laser Interference Principle

The tonometer is widely used in clinical test for the diagnosis and treatment of ophthalmological diseases.The conventional contact-type tonometer has such defects as contact injury,cross infection,and poor comfort;the existing non-contact tonometer also has many flaws,such as great measurement error in case of shape change,large volume,complex structure,and low degree of automation.Considering that,in this subject,we design and study a non-contact tonometer control system based on the principle of laser interference,laying a theoretical foundation for the development of the non-contact type and facilitating the diagnosis of ophthalmic diseases.First,on the basis of analyzing the principle of laser interference,the function relationship between interference fringe and intraocular pressure is obtained.Then,the overall plan of the non-contact tonometer control system is proposed,and the control plans of the alignment module,pulse drive and control module,and signal acquisition and processing module are determined.Moreover,the hardware circuits and software programs are designed for them.Finally,the software is designed for the upper computer of the control system with Lab VIEW,achieving good human-computer interaction,and the three control modules are commissioned.The test results show that the control system designed in this subject has an intraocular pressure measurement range: 8-60 mm Hg,with the standard deviation: ± 8 mm Hg,and display resolution: 0.5 mm Hg,reaching the main technical indicators specified in this paper.