Department of Ophthalmology, Save Sight Institute, University of Sydney, NSW, Sydney, Australia.
Invest Ophthalmol Vis Sci. 2010 May;51(5):2770-7. doi: 10.1167/iovs.09-4577. Epub 2009 Dec 30.
Acute optic neuritis (ON) is often followed by recovery of visual function. Although this recovery is mainly attributable to resolution of the acute inflammation, the redistribution of ion channels along the demyelinated membrane, and subsequent remyelination, part of it may be the result of neural plasticity. In the present study, the interrelationship was examined between structural (retinal nerve fiber layer [RNFL] thickness) and functional (amplitude of multifocal visual evoked potentials [mfVEPs]) measures of the integrity of the visual pathway in the postacute stage of ON, to determine whether there was any evidence of ongoing neural reorganization.
Twenty-five subjects with acute unilateral ON underwent serial RNFL thickness measurement and mfVEP recording. The inter-eye asymmetry of both measures was analyzed. In the period between 6 and 12 months, the subjects were considered free of optic disc edema, and that period was used to analyze the structure-function relationship. Twenty control subjects were also examined.
There were significant but opposite changes in RNFL thickness and mfVEP amplitude. The average asymmetry of RNFL thickness between affected and fellow eyes increased from 17.5 +/- 11.5 to 21.1 +/- 12.8 microm (P = 0.0003), indicating progressive axonal loss, whereas mfVEP amplitude asymmetry decreased from 46.6 +/- 32.4 to 38.3 +/- 31.1 nV (P = 0.0015), indicating continuous functional recovery. In comparison to the 6-month results, the mfVEP amplitude in the ON eye improved by 17.8%, whereas RNFL thickness decreased by 20.8%. The result remained unchanged regardless of the degree of optic nerve remyelination.
The finding of structural-functional discrepancy at the postinflammatory stage may support the concept that neural plasticity contributes to functional recovery after acute ON.
急性视神经炎（ON）常伴有视觉功能的恢复。尽管这种恢复主要归因于急性炎症的消退、脱髓鞘膜上离子通道的重新分布以及随后的髓鞘再生，但部分原因可能是神经可塑性的结果。本研究旨在探讨急性 ON 后恢复期视觉通路的结构（视网膜神经纤维层[RNFL]厚度）和功能（多焦视觉诱发电位[mfVEP]振幅）测量之间的相互关系，以确定是否有任何证据表明存在持续的神经重组。
25 例单侧急性 ON 患者接受了连续的 RNFL 厚度测量和 mfVEP 记录。分析了两种测量方法的眼间不对称性。在 6 至 12 个月期间，患者被认为没有视盘水肿，该期间用于分析结构-功能关系。还对 20 名对照者进行了检查。
RNFL 厚度和 mfVEP 振幅均有显著但相反的变化。受累眼与对侧眼之间的 RNFL 厚度平均不对称性从 17.5 ± 11.5 μm 增加到 21.1 ± 12.8 μm（P = 0.0003），表明轴突进行性丢失，而 mfVEP 振幅不对称性从 46.6 ± 32.4 nV 降低至 38.3 ± 31.1 nV（P = 0.0015），表明持续的功能恢复。与 6 个月的结果相比，ON 眼的 mfVEP 振幅提高了 17.8%，而 RNFL 厚度降低了 20.8%。无论视神经髓鞘再生程度如何，结果均保持不变。
在炎症后阶段发现结构-功能差异可能支持神经可塑性有助于急性 ON 后功能恢复的概念。
