Cao Dingcai, Pokorny Joel, Grassi Michael A
Department of Surgery, Section of Ophthalmology and Visual Science, The University of Chicago, IL 60637, USA.
Doc Ophthalmol. 2011 Aug;123(1):29-41. doi: 10.1007/s10633-011-9279-9. Epub 2011 Jun 24.
The purpose of this study was to evaluate the feasibility of measuring rod and cone electroretinograms (ERGs) at a single mesopic adaptation level. To accomplish this, a four-primary photostimulator was implemented using a commercially available ERG system (Diagnosys ColorDome) to generate three types of stimuli that temporally modulated rods alone, cones alone, and rods and cones simultaneously. For each stimulus type, ERGs were recorded as a function of temporal frequency (2, 4, 8, or 16 Hz) and mesopic light levels (0.02, 0.16, or 1.26 cd/m(2)) in normal observers and patients with retinitis pigmentosa (RP) or cone-rod degeneration. The normal observers ERG waveforms showed a clear periodic pattern, mirroring the sinusoidal stimuli. At all light levels, rod responses were always higher than cone responses for temporal frequencies between 2 and 8 Hz, suggesting that rods dominated the responses. Cone responses were minimal at the lowest light level and increased with increases in light level. The amplitude of the response to the combined stimuli was intermediate between that of the isolated cone and the isolated rod stimuli for all light levels. Good receptoral isolation was confirmed by the results showing (1) minimal or no rod ERGs but recordable cone ERGs in the patients and (2) high correlation between the ERG amplitudes obtained from the four-primary method and those from the ISCEV standard clinical protocol in normal observers.
本研究的目的是评估在单一中间视觉适应水平下测量视杆和视锥细胞视网膜电图（ERG）的可行性。为实现这一目的，使用市售的ERG系统（Diagnosys ColorDome）构建了一种四原色光刺激器，以产生三种类型的刺激，分别单独对视杆细胞、视锥细胞进行时间调制，以及同时对视杆和视锥细胞进行时间调制。对于每种刺激类型，在正常观察者以及患有色素性视网膜炎（RP）或视锥 - 视杆细胞营养不良的患者中，记录ERG作为时间频率（2、4、8或16 Hz）和中间视觉光水平（0.02、0.16或1.26 cd/m²）的函数。正常观察者的ERG波形显示出清晰的周期性模式，与正弦刺激相对应。在所有光水平下，对于2至8 Hz的时间频率，视杆细胞反应始终高于视锥细胞反应，这表明视杆细胞主导了反应。视锥细胞反应在最低光水平时最小，并随光水平增加而增加。对于所有光水平，对组合刺激的反应幅度介于孤立视锥细胞和孤立视杆细胞刺激的反应幅度之间。结果证实了良好的感受器隔离，表现为：（1）患者中视杆细胞ERG最小或无，但视锥细胞ERG可记录；（2）正常观察者中，通过四原色方法获得的ERG幅度与国际临床视觉电生理学会（ISCEV）标准临床方案获得的ERG幅度之间具有高度相关性。
