一种眼轴长度测量系统的设计实现及其关键技术研究

Design and implementation of eye axis length measurement system and research on its key technologies

目的:设计一套眼轴长度测量系统,对其关键技术进行研究,并通过该系统获取眼轴长度及眼组织内各界面之间的位置信息。方法:采用中心波长为1 060 nm、半波宽度为50 nm的超辐射发光二极管(super luminescent diode,SLD)作为系统光源,基于光学相干技术搭建测量光路,并设计测量控制系统。该系统由测量光路和测量控制系统组成。通过计算机编程驱动运动控制卡实现系统控制,由步进电动机带动调焦透镜进行同步位移实现焦点同步,使用数据采集卡实现快速采集,结合位移编码器实现高精度测量。测量数据通过数据采集卡传输至计算机处理并显示。结果:通过自制测试模块进行系统测量实验,准确测得了测试模块不同反射界面之间的位置关系,且精度在微米量级。对人眼进行了初步测量实验,获得了眼轴长度及眼组织内各界面位置信息,结果与超声测量方法有较好的一致性。结论:设计的眼轴长度测量系统利用焦点同步技术可以快速、准确地实现眼轴长度的测量,为眼科疾病的诊治等提供理论依据。

Objective To design a set of eye axis length measurement system and study its key technologies to obtain the axial length and position information between the interfaces in the eye tissue through the system.Methods A super luminescent diode(SLD)with a center wavelength of 1 060 nm and half wavelength of 50 nm was selected as the light source,and the measuring optical path was constructed based on the optical coherence technology,and the measurement and control system was designed.The system consisted of a measurement optical path and a measurement control sub system.The system control was realized through the motion control card driven by computer programming,and the synchronization of the focus was implemented by using the synchronous displacement of the focusing lens driven by the stepper motor,and the fast sampling was achieved by using the data acquisition card,and the high precision measurement was achieved by combining the displacement encoder.The measured data were transmitted to the computer for processing and display through the data acquisition card.Results A measurement experiment was executed through a self-made test module,and the positional relationship was measured between different reflective interfaces of the test module accurately,with the accuracy being on the order of microns.A preliminary measurement was conducted on the human eye,and the length of the eye axis and the position information of each interface in the eye tissue were obtained,which had good consistency with those by ultrasonic measurement methods.Conclusion The axial length measurement system developed realizes the measurement of the length of the axial length quickly and accurately by using the focus synchronization technology,and it can provide theoretical basis for the diagnoses and treatment of ophthalmic diseases.[Chinese Medical Equipment Journal,2019,40(3):1-6]