Johnson C A, Post R B, Tsuetaki T K
Ophthalmic Physiol Opt. 1984;4(4):319-25.
Previous investigations have shown that, in dim illumination and empty visual fields, accommodation in most observers is for an intermediate distance referred to as the dark focus or resting focus of accommodation. Dynamic properties of the resting focus were examined in the present study with a high-speed infrared optometer. All subjects displayed fluctuations of accommodation in darkness that were primarily characterized by frequency components below 0.5 Hz. These fluctuations were substantially attenuated during cycloplegia or viewing a bright, high-contrast target. Both the mean resting-focus position and the magnitude of fluctuations varied from one subject to another and from day-to-day. A weak association was found between the mean a standard deviation of accommodation responses in the dark. The present findings suggest that the accommodation mechanism in most observers is somewhat unstable under degraded viewing conditions. In addition, the mean resting-focus value for a large sample of subjects was found to be lower for i.r. optometer measurements than for previous investigations employing a laser optometer.
先前的研究表明，在昏暗照明和视野空旷的情况下，大多数观察者的眼睛调节是针对一个被称为暗焦点或静息焦点的中间距离。在本研究中，使用高速红外验光仪对静息焦点的动态特性进行了检查。所有受试者在黑暗中均表现出眼睛调节的波动，其主要特征是频率成分低于0.5Hz。在睫状肌麻痹期间或观看明亮、高对比度目标时，这些波动会大幅减弱。静息焦点的平均位置和波动幅度在不同受试者之间以及不同日期有所不同。在黑暗中，眼睛调节反应的平均值与标准差之间存在微弱的关联。目前的研究结果表明，在视觉条件较差的情况下，大多数观察者的眼睛调节机制有些不稳定。此外，发现大量受试者的静息焦点平均值在使用红外验光仪测量时比之前使用激光验光仪的研究结果要低。
