Stewart Peter S, Jensen Oliver E, Foss Alexander J E
School of Mathematics and Statistics, University of Glasgow, Glasgow, United Kingdom.
School of Mathematics, University of Manchester, Manchester, United Kingdom.
Invest Ophthalmol Vis Sci. 2014 Sep 4;55(10):6319-23. doi: 10.1167/iovs.14-14331.
There is no easy way to estimate the intracranial pressure (ICP) noninvasively. The retinal vein can exhibit large amplitude oscillations at the level of the lamina cribrosa under certain circumstances. The aims of this study were to develop a theoretical understanding of the conditions required to establish this vigorous oscillatory behavior and to determine whether observations of it could lead to a noninvasive estimate of the ICP.
A mathematical model was constructed in which the central retinal vein was modeled as 2 Starling resistors in series, 1 located in the eye and the other in the cerebrospinal fluid (CSF) space, separated by a region where it was not collapsible, corresponding to its course within the optic nerve itself. Intraocular pressure (IOP) and ICP were modeled as sinusoidal wave forms.
The model predicted an approximately linear relationship between the IOP and the ICP at the point of onset of oscillatory behavior. The predicted onset IOP also depended weakly on the retinal blood flow rate and on vein diameter and was only mildly sensitive to the phase difference between the two pressure waveforms. The predicted onset curve showed encouraging agreement with measurements in canines.
The model suggested that it may be possible to estimate the ICP from observations of the retinal venous pulse by using a modified form of ophthalmodynamometry.
目前尚无简单的非侵入性方法来估计颅内压（ICP）。在某些情况下，视网膜静脉在筛板水平可表现出大幅度振荡。本研究的目的是从理论上理解产生这种强烈振荡行为所需的条件，并确定对其进行观察是否能实现对颅内压的非侵入性估计。
构建了一个数学模型，其中视网膜中央静脉被建模为两个串联的斯塔林电阻，一个位于眼内，另一个位于脑脊液（CSF）空间，两者之间由一个不可塌陷的区域隔开，该区域对应于视神经内的静脉行程。眼内压（IOP）和颅内压被建模为正弦波形。
该模型预测，在振荡行为开始时，眼内压和颅内压之间存在近似线性关系。预测的起始眼内压还与视网膜血流速率和静脉直径存在弱相关性，并且对两个压力波形之间的相位差仅具有轻度敏感性。预测的起始曲线与犬类测量结果显示出令人鼓舞的一致性。
该模型表明，通过使用改良形式的眼动态测量法，有可能根据视网膜静脉搏动的观察结果来估计颅内压。
