全息光栅法视网膜调制传递函数测定装置的实验研究

目的验证在光学实验平台上利用全息光栅法及“0”级空间滤过法搭建的调制传递函数（modulation transfer function，MTF）测量装置的可行性，从而为今后该种仪器的顺利开发、生产做好相关理论和实验的基础工作。方法利用全息光栅法及“0”级空间滤过法在光具座上搭建视网膜调制传递函数测定实验装置．并进行一般人群测量，根据所测量结果与25例正常人（50眼）的调制传递函数进行比较分析。结果用本实验装置所测量的MTF曲线结果为：MTF的峰值位于中空间频率区6cpd，在低频区和高频区MTF呈下降趋势，曲线表现一倒置的“U”字形，符合人眼MTF的特点。结论本实验装置经过初步试用表明，利用全息光栅法及“O”级空间滤过法制作的视网膜调制传递函数测定装置所测人眼的MtF曲线特征，与正常人眼MTF值的符合性好，为今后开发基于全息光栅法及“O”级空间滤过法的人眼调制传递函数测量产品提供了可靠的实验依据。

A study on the feasibility of retina modulation transfer function measuring equipment using a holographic grating

Objective To prove the feasibility of obtaining better modulation transfer function （MTF） and contrast sensitivity function （CSF） measurements using experimental MTF measuring equipment that based on holographic grating principles and the blockage of zero phase light diffraction; to test theories in design and gain experience by using a new MTF measuring device for use in the future. Methods The MTF measuring equipment was designed for an optical bench using holographic gratings and blocking the transmis- sion of zero phase light diffraction. The prototype device was used to measure the CSF of 25 normal people to see if these measurements compared to expected results. Results The curve of the CSF was in accordance with the characteristics of human MTF curves, which were shaped like a reverse ＇U＇. The peak of the CSF curve corresponded to a spatial frequency of 6 c/d, and the downward slopes of the curve occurred at the low and high spatial frequency spans. Conclusion The CSF curve is in accordance with charac- teristics of the human CSF, which offers experimental proof for inventing new MTF measuring equipment based on holographic grating principles and blocking the transmission of zero phase light diffraction.