Anderton P J, Millar T J
VisionTest Australia, Eye and Vision Research Foundation, Sydney, NSW.
Doc Ophthalmol. 2000;100(2-3):207-29.
To look for a subcomponent of the mFERG generated at the optic nerve head and increasing in latency with distance from it. To compare multifocal electroretinogram (mFERG, mPERG) changes to those in full field ERGs and transient and steady state pattern and focal ERGs (PERGs, FERGs) in cats with total unilateral optic nerve section.
We recorded multifocal flash ERGs (mFERGs) at three levels of intensity and multifocal pattern ERGs (mPERGs) within 61 equal areas after total unilateral optic nerve section in five long term (> 18 month) survival cats, as part of a long term serial study of full field flash and pattern ERG changes to many stimuli, in a larger population. Cats were anaesthetised with Ketamine/Xylazine and wore Henkes electrodes with 6mm artificial pupils. Intact retinal circulation was verified by fluorescein angiography and optic nerve section by retinal photography and histology. We compared the mean and mean summed multifocal responses, from the normal and denervated eyes. We also compared the mean interocular difference around the area centralis and as a function of distance from the optic nerve head, across the horizontal meridian for the mFERG to the most intense stimulus. The degree of change was compared to that in other types of ERG, in the larger set of cats.
mFERGs were similar across cats. Response density was flat with no prominence at the area centralis. Average summed mFERGs were similar in the normal and denervated eye. In the interocular differences a component near OP2 was reduced in the first kernel to the most intense stimulus, near OP1 and OP3 in the second kernel and locally, there was a hint of a component near OP2, which varied in latency in a ring around the disk and at the area centralis. Nevertheless, no component could be seen, varying in latency with distance from the optic nerve head, across the horizontal meridian. No mPERG was recordable in these conditions. Full field PERGs and FERGs were very reduced. Full field flash ERG amplitude changes were small (4-20%) and slower to appear than PERG changes. Degree of ERG reduction and correlation with PERG losses was greatest for the mesopic OPs, low for the scotopic tests (STR, ERG and OPs) and near zero for the mesopic ERG. The mFERG and mesopic ERG both lost OPs without overall amplitudes.
The cat mFERG does not have a component, varying in latency with distance from the optic nerve head. The only change was qualitiatively similar to that in the light adapted ERG. With intense stimuli there were local changes around the time of OP2 near the area centralis which might be explained by local variations in ganglion cell density.
寻找在视神经乳头产生且潜伏期随距其距离增加的多焦视网膜电图（mFERG）子成分。比较单侧视神经完全切断的猫的多焦视网膜电图（mFERG、多焦图形视网膜电图（mPERG））变化与全视野视网膜电图以及瞬态和稳态图形及局灶性视网膜电图（PERG、FERG）变化。
作为对全视野闪光和图形视网膜电图对多种刺激变化的长期系列研究的一部分，我们在5只长期存活（>18个月）的猫单侧视神经完全切断后，记录了三个强度水平的多焦闪光视网膜电图（mFERG）以及61个等面积区域内的多焦图形视网膜电图（mPERG）。猫用氯胺酮/赛拉嗪麻醉，佩戴带有6mm人工瞳孔的亨克斯电极。通过荧光素血管造影术验证视网膜循环正常，通过视网膜摄影和组织学检查验证视神经切断情况。我们比较了正常眼和去神经眼的平均及平均总和多焦反应。我们还比较了黄斑中心凹周围以及作为距视神经乳头距离的函数的平均眼间差异，在水平子午线上针对mFERG对最强刺激的情况进行比较。将变化程度与更大组猫中其他类型视网膜电图的变化程度进行比较。
不同猫之间的mFERG相似。反应密度平坦，在黄斑中心凹处无突出。正常眼和去神经眼的平均总和mFERG相似。在眼间差异中，对于最强刺激，靠近OP2的一个成分在第一个核中减少，在第二个核中靠近OP1和OP3处减少，并且在局部，有一个靠近OP2的成分的迹象，其潜伏期在视盘周围的环以及黄斑中心凹处有所变化。然而，在水平子午线上，未发现有成分的潜伏期随距视神经乳头的距离而变化。在这些条件下无法记录到mPERG。全视野PERG和FERG明显降低。全视野闪光视网膜电图振幅变化较小（4 - 20%），且比PERG变化出现得慢。视网膜电图降低程度以及与PERG损失的相关性在中视OPs时最大，在暗视测试（STR、视网膜电图和OPs）时较低，在中视视网膜电图时接近零。mFERG和中视视网膜电图都失去了OPs但总体振幅未变。
猫的mFERG没有一个潜伏期随距视神经乳头距离变化的成分。唯一的变化在性质上与明适应视网膜电图的变化相似。在强刺激下，黄斑中心凹附近OP2时间附近有局部变化，这可能由神经节细胞密度的局部变化来解释。
