Winn B, Pugh J R, Gilmartin B, Owens H
Department of Vision Sciences Aston University, Birmingham, U.K.
Vision Res. 1990;30(7):1093-9. doi: 10.1016/0042-6989(90)90117-4.
Temporal variations in the nominally steady-state accommodation response can be characterized approximately by two principal regions of dominant activity: a low frequency region (LFR less than 0.6 Hz) and a high frequency region (HFR greater than 1.0 Hz). The observed changes of activity in the LFR induced by varying stimulus conditions has led to the proposal that this region may be utilized as an error detector in the accommodation feed-back loop. The role of fluctuations in the HFR is, however, equivocal particularly as several reports have shown their magnitude to be positively correlated with pupil size. The implication is that HFRs are a consequence of the mechanical and elastic properties of peripheral rather than central zones of the crystalline lens and hence do not contribute to the accommodation control process. The aim of the study was to compare the incidence and magnitude of microfluctuations in LFRs and HFRs for central and peripheral lens zones when viewing a near target. Accommodation was measured continuously with a modified Canon Autoref R1 infra-red optometer on five young emmetropic subjects. We show that although the total power of the microfluctuations is reduced in the periphery, the form of the power spectra is similar for central and peripheral zones. Thus rather than being spurious effects caused by the periphery of the lens HFRs are present for both central and peripheral lens zones.
一个低频区域（LFR小于0.6Hz）和一个高频区域（HFR大于1.0Hz）。不同刺激条件下LFR中观察到的活动变化促使人们提出，该区域可能被用作调节反馈回路中的误差检测器。然而，HFR波动的作用尚不清楚，特别是因为有几份报告表明它们的幅度与瞳孔大小呈正相关。这意味着HFR是晶状体周边而非中央区域的机械和弹性特性的结果，因此对调节控制过程没有贡献。本研究的目的是比较在观看近目标时，中央和周边晶状体区域LFR和HFR中微波动的发生率和幅度。使用改良的佳能自动验光仪R1型红外验光仪对五名年轻正视眼受试者的调节进行连续测量。我们发现，虽然周边区域微波动的总功率降低了，但中央和周边区域的功率谱形式相似。因此，HFR并非由晶状体周边引起的虚假效应，中央和周边晶状体区域均存在HFR。
