Jacks A S, Miller N R
Selly Oak Hospital, Block K, Raddlebarn Road, Birmingham B29 6JD, UK.
J Neurol Neurosurg Psychiatry. 2003 Jan;74(1):7-9. doi: 10.1136/jnnp.74.1.7.
Spontaneous retinal venous pulsation is seen as a subtle variation in the calibre of the retinal vein(s) as they cross the optic disc. The physical principles behind the venous pulsations has been the point of much debate. Initial theories suggested that the pulsation occurred because of the rise in intraocular pressure in the eye with the pulse pressure. This article presents an argument that this is not the case. The pulsations are in fact caused by variation in the pressure gradient along the retinal vein as it traverses the lamina cribrosa. The pressure gradient varies because of the difference in the pulse pressure between the intraocular space and the cerebrospinal fluid. The importance of this is that as the intracranial pressure rises the intracranial pulse pressure rises to equal the intraocular pulse pressure and the spontaneous venous pulsations cease. Thus it is shown that cessation of the spontaneous venous pulsation is a sensitive marker of raised intracranial pressure. The article discusses the specificity of the absence of spontaneous venous pulsation and describes how the patient should be examined to best elicit this important sign.
自发性视网膜静脉搏动表现为视网膜静脉在穿过视盘时管径的细微变化。静脉搏动背后的物理原理一直是诸多争论的焦点。最初的理论认为，搏动是由于眼内压随脉压升高而产生的。本文提出观点认为并非如此。实际上，搏动是由视网膜静脉穿过筛板时沿静脉的压力梯度变化引起的。压力梯度变化是由于眼内空间与脑脊液之间脉压的差异。其重要性在于，随着颅内压升高，颅内脉压升高至与眼内脉压相等，自发性静脉搏动就会停止。因此表明，自发性静脉搏动停止是颅内压升高的一个敏感指标。本文讨论了自发性静脉搏动缺失的特异性，并描述了应如何检查患者以最佳引出这一重要体征。
