Wang L
St Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.
Acta Ophthalmol Suppl (1985). 1994(212):1-50.
The purpose of the present study was to establish a method for objective measurements of visual readaptation after flash exposures and to define a model for measurements. Influences of target direction, luminance and velocity on optokinetic nystagmus (OKN) were investigated under scotopic conditions. Visual readaptation was measured using OKN as an indicator of visual perception after exposure to a flash. The interval between the triggering of the flash and the reoccurrence of OKN was defined as the visual readaptation time (RAT). A Goldmann perimeter hemisphere was used for flash stimulation. A horizontally moving vertical grating projected inside the hemisphere was used as the OKN stimulus. Eye movements were recorded by DC electrooculography (EOG). The dependence of RAT on the dose of the flash, the wavelength of the flash and the luminance of the OKN target were investigated. The precision of the measurement method was studied. This includes the analysis of the variance due to the experimental occasions, the repeated exposures, the sexes of the subjects, the methods for recognition of OKN and the ways of visual adaptation before measurements. The contributions of retinal receptor and the neural activity to RAT were investigated by electroretinography (ERG). The influences of target direction and luminance on binocular motion perception and OKN as well as monocular OKN were examined at various target velocities. The dependence of the frequency and amplitude of eye jerks during monocular OKN on target luminance and velocity were also examined. It was found that RAT increases with increasing doses of the flash or decreasing luminance of the grating. RAT is most extended after flashes near 520 nm. RAT does not differ between experimental occasions, between a manual and a semi-automatic method for recognition of OKN, between the sexes and between goggle adaptation and ordinary dark adaptation. There is a reduction of RAT due to repeated flash exposures. The data collected indicate that a well-defined model is crucial for measurements of RAT. The measurement of ERG showed that RAT is mediated by both retinal receptor and the neural activities. The receptor component depends on the wavelength of the flash while the neural component is wavelength-independent. Moreover, it was found that motion perception and OKN gain does not differ between right and left target directions. For a given target velocity, motion perception and OKN gain under both binocular and monocular viewing conditions increase with increasing luminance of the target with an exponential decay. The maximum OKN gain decreases as target velocity increases.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究的目的是建立一种客观测量闪光暴露后视觉再适应的方法，并定义一种测量模型。在暗视条件下，研究了目标方向、亮度和速度对视动性眼震（OKN）的影响。使用OKN作为闪光暴露后视觉感知的指标来测量视觉再适应。将闪光触发与OKN再次出现之间的间隔定义为视觉再适应时间（RAT）。使用戈德曼周边视野半球进行闪光刺激。将投射在半球内的水平移动垂直光栅用作OKN刺激。通过直流眼电图（EOG）记录眼球运动。研究了RAT对闪光剂量、闪光波长和OKN目标亮度的依赖性。研究了测量方法的精度。这包括对实验次数、重复暴露、受试者性别、OKN识别方法以及测量前视觉适应方式所导致的方差分析。通过视网膜电图（ERG）研究了视网膜感受器和神经活动对RAT的贡献。在不同目标速度下，研究了目标方向和亮度对双眼运动感知和OKN以及单眼OKN的影响。还研究了单眼OKN期间眼跳频率和幅度对目标亮度和速度的依赖性。结果发现，RAT随闪光剂量增加或光栅亮度降低而增加。在接近520 nm的闪光后，RAT延长最多。RAT在实验次数之间、OKN识别的手动和半自动方法之间、性别之间以及护目镜适应和普通暗适应之间没有差异。由于重复闪光暴露，RAT会降低。收集的数据表明，一个明确的模型对于RAT的测量至关重要。ERG测量表明，RAT由视网膜感受器和神经活动介导。感受器成分取决于闪光波长，而神经成分与波长无关。此外，发现左右目标方向之间的运动感知和OKN增益没有差异。对于给定的目标速度，双眼和单眼观察条件下的运动感知和OKN增益随目标亮度增加呈指数衰减增加。最大OKN增益随目标速度增加而降低。（摘要截于400字）
