Institute of Telecommunications, Technical University of Darmstadt, Darmstadt 64383, Germany.
IEEE Trans Biomed Eng. 2010 Feb;57(2):373-83. doi: 10.1109/TBME.2009.2032531. Epub 2009 Sep 29.
The role of cardiopulmonary signals in the dynamics of wavefront aberrations in the eye has been examined. Synchronous measurement of the eye's wavefront aberrations, cardiac function, blood pulse, and respiration signals were taken for a group of young, healthy subjects. Two focusing stimuli, three breathing patterns, as well as natural and cycloplegic eye conditions were examined. A set of tools, including time-frequency coherence and its metrics, has been proposed to acquire a detailed picture of the interactions of the cardiopulmonary system with the eye's wavefront aberrations. The results showed that the coherence of the blood pulse and its harmonics with the eye's aberrations was, on average, weak ( 0.4+/-0.15), while the coherence of the respiration signal with eye's aberrations was, on average, moderate ( 0.53+/-0.14). It was also revealed that there were significant intervals during which high coherence occurred. On average, the coherence was high ( > 0.75) during 16% of the recorded time, for the blood pulse, and 34% of the time for the respiration signal. A statistically significant decrease in average coherence was noted for the eye's aberrations with respiration in the case of fast controlled breathing (0.5 Hz). The coherence between the blood pulse and the defocus was significantly larger for the far target than for the near target condition. After cycloplegia, the coherence of defocus with the blood pulse significantly decreased, while this was not the case for the other aberrations. There was also a noticeable, but not statistically significant, increase in the coherence of the comatic term and respiration in that case. By using nonstationary measures of signal coherence, a more detailed picture of interactions between the cardiopulmonary signals and eye's wavefront aberrations has emerged.
研究了心肺信号在眼球波前像差动态中的作用。对一组年轻健康的受试者进行了眼球波前像差、心脏功能、血液脉搏和呼吸信号的同步测量。检查了两种调焦刺激、三种呼吸模式以及自然和散瞳状态。提出了一组工具，包括时频相干及其度量，以详细了解心肺系统与眼球波前像差的相互作用。结果表明，血液脉搏及其谐波与眼球像差的相干性平均较弱（0.4+/-0.15），而呼吸信号与眼球像差的相干性平均适中（0.53+/-0.14）。还发现存在相干性高的显著间隔。平均而言，血液脉搏的相干性在记录时间的 16%（>0.75），呼吸信号的相干性在 34%的时间内较高。在快速控制呼吸（0.5 Hz）的情况下，呼吸时眼球像差的平均相干性显着降低。远目标条件下血液脉冲与离焦的相干性明显大于近目标条件。散瞳后，离焦与血液脉搏的相干性显着降低，但其他像差则不然。在这种情况下，彗差项和呼吸的相干性也有明显但无统计学意义的增加。通过使用信号相干性的非平稳测量，可以更详细地了解心肺信号与眼球波前像差之间的相互作用。
