van der Heijde G L, Beers A P, Dubbelman M
Department of Medical Physics and Informatics, Free University Hospital, Amsterdam, The Netherlands.
Ophthalmic Physiol Opt. 1996 May;16(3):216-21. doi: 10.1046/j.1475-1313.1996.95000518.x.
Over the past 30 years investigators have noted fluctuations in accommodation when the eye views a stationary target. These microfluctuations have been studied mainly with the use of infrared optometers. Two dominant components have been found: a low frequency component (LFC; 0.05-0.5 Hz) and a high frequency component (HFC; 1.0-2.2 Hz). The LFC probably has a neurological origin. The HFC is supposed to be related to the arterial pulse. The aim of this study was to investigate accommodative fluctuations and gain more information about their origin by using a non-optical method. We used continuous ultrasonographic biometry to measure changes in anterior chamber (AC) depth, lens thickness and vitreous length during steady-state accommodation. Simultaneously, the electrocardiogram (ECG) was recorded. Changes in axial length were calculated offline by taking the sum of the changes in the three intraocular distances. Results show that fluctuations with an LFC were present in all three intraocular distances but not in the axial length, proving that only the lens was involved. In contrast with the findings of investigators using optical methods, no HFC was present in fluctuations of AC depth and lens thickness. However, a small HFC was found in registrations of the vitreous and axial length, which appeared to correspond with the heart rate.
在过去30年里，研究人员注意到当眼睛注视一个静止目标时，调节存在波动。这些微小波动主要通过红外验光仪进行研究。已发现两个主要成分：一个低频成分（LFC；0.05 - 0.5赫兹）和一个高频成分（HFC；1.0 - 2.2赫兹）。低频成分可能源于神经方面。高频成分被认为与动脉搏动有关。本研究的目的是通过使用一种非光学方法来研究调节波动并获取更多关于其起源的信息。我们使用连续超声生物测量法来测量稳态调节期间前房（AC）深度、晶状体厚度和玻璃体长度的变化。同时，记录心电图（ECG）。通过求取三个眼内距离变化的总和离线计算眼轴长度的变化。结果表明，所有三个眼内距离都存在低频成分的波动，但眼轴长度不存在，这证明只有晶状体参与其中。与使用光学方法的研究人员的发现相反，前房深度和晶状体厚度的波动中不存在高频成分。然而，在玻璃体和眼轴长度的记录中发现了一个小的高频成分，它似乎与心率相对应。
