Arai M, Lopes de Faria J M, Hirose T
Schepens Retina Associates, Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston 02114, MA, USA.
Jpn J Ophthalmol. 1999 Nov-Dec;43(6):481-9. doi: 10.1016/s0021-5155(99)00119-7.
To investigate how the multifocal electroretinogram (ERG) is altered in conditions of blocking, light scattering, or distortion of the stimulus that are seen in ocular pathologies.
A central 40 degree-diameter stimulus pattern consisting of 61 hexagons was presented on a cathode ray tube monitor at a rate of 75 Hz according to the pseudo-random binary M sequence by the Veris computer program. Localized responses corresponding to each hexagon and ERG topographies were displayed on the computer screen. Central scotoma was simulated by blocking the central area of the stimulus, visual field constriction by blocking the outer area of the stimulus, mild cataract by using acrylic filters that caused light scatter, and epiretinal membrane by using a wavy plastic plate that produced metamorphopsia.
The responses from the blocked area were nonrecordable whether blockage was central or peripheral; responses from the adjacent unblocked area had a larger amplitude when large areas of the stimulus were blocked. The light scatter that decreased vision from 20/20 to 20/70 did not significantly decrease response amplitudes. Responses from areas in which the stimulus pattern was distorted were minimally affected.
The results show that the system records local ERGs from the macula and outside the macula. It can detect the area where the stimulus is blocked. Moderate light scattering and distortion do not cause loss of local ERG characteristics.
研究在眼部疾病中出现的刺激阻断、光散射或变形情况下，多焦视网膜电图（ERG）是如何改变的。
通过Veris计算机程序，按照伪随机二进制M序列，以75赫兹的速率在阴极射线管显示器上呈现由61个六边形组成的直径为40度的中央刺激图案。与每个六边形对应的局部反应和ERG地形图显示在计算机屏幕上。通过阻断刺激的中央区域模拟中心暗点，通过阻断刺激的外部区域模拟视野缩窄，使用导致光散射的丙烯酸滤光片模拟轻度白内障，使用产生视物变形的波浪形塑料板模拟视网膜前膜。
无论阻断是在中央还是周边，阻断区域的反应均无法记录；当刺激的大片区域被阻断时，相邻未被阻断区域的反应幅度更大。使视力从20/20降至20/70的光散射并未显著降低反应幅度。刺激图案变形区域的反应受影响最小。
结果表明该系统可记录黄斑区和黄斑区以外的局部ERG。它能检测到刺激被阻断的区域。中度光散射和变形不会导致局部ERG特征丧失。
