Michelson G, Groh M, Gründler A
Department of Ophthalmology, University Erlangen-Nürnberg, Germany.
Br J Ophthalmol. 1994 Jun;78(6):461-5. doi: 10.1136/bjo.78.6.461.
The blood flow in the uvea in cats and monkeys during acute increases of arterial blood pressure is well controlled by a sympathetic mechanism protecting the eye from overperfusion. Ocular macrocirculation (ophthalmic artery) and ocular microcirculation (iris) were examined in 22 healthy subjects during acute increases of arterial blood pressure induced by physical exercise (125 W). With a data acquisition and storage software in real time mode several parameters of ocular perfusion and systemic functions were measured simultaneously. Blood flow parameters were measured in the ophthalmic artery by pulsed Doppler sonography and in the iris by laser Doppler flowmetry. Systolic, diastolic, and mean velocities of the ophthalmic artery peak velocity pulse curve, the ophthalmic artery mean velocity pulse curve, and the iris velocity pulse curve were estimated off line. The ophthalmic artery mean velocity pulse curve resembles the integrated velocity of all erythrocytes in the vessel including the slowly running cells near the vessel wall. The iris velocity pulse curve was calculated by a special statistic procedure (ALDF). After exercise there was a significant increase in systolic and diastolic blood pressure and heart rate. The pulse curve of the ophthalmic artery showed significantly increased systolic and decreased diastolic velocities. The vascular resistance of the branches of the ophthalmic artery increased significantly. The iridal vasculature showed no significant change in blood cell velocity but an increased vascular resistance. It was observed that the elevated perfusion pressure was associated with an increased vascular resistance and a constant mean blood velocity in the ophthalmic artery and iridal vessels. The parallel elevation of vascular resistance and blood pressure during exercise may be the reason for a constant blood flow in the ophthalmic artery and the iris. This may be accounted for by a sympathetic mechanism for protecting the eye from overperfusion.
在猫和猴子中，当动脉血压急性升高时，葡萄膜中的血流通过一种交感神经机制得到良好控制，该机制可保护眼睛免于过度灌注。在22名健康受试者进行体育锻炼（125瓦）导致动脉血压急性升高期间，对眼部大循环（眼动脉）和眼部微循环（虹膜）进行了检查。使用数据采集和存储软件的实时模式，同时测量了眼部灌注和全身功能的几个参数。通过脉冲多普勒超声在眼动脉中测量血流参数，通过激光多普勒血流仪在虹膜中测量血流参数。离线估计眼动脉峰值速度脉冲曲线、眼动脉平均速度脉冲曲线和虹膜速度脉冲曲线的收缩期、舒张期和平均速度。眼动脉平均速度脉冲曲线类似于血管中所有红细胞的综合速度，包括靠近血管壁缓慢流动的细胞。虹膜速度脉冲曲线通过特殊统计程序（ALDF）计算得出。运动后，收缩压、舒张压和心率显著升高。眼动脉的脉冲曲线显示收缩期速度显著增加，舒张期速度降低。眼动脉分支的血管阻力显著增加。虹膜血管系统的血细胞速度没有显著变化，但血管阻力增加。观察到灌注压升高与眼动脉和虹膜血管的血管阻力增加以及平均血流速度恒定有关。运动期间血管阻力和血压的平行升高可能是眼动脉和虹膜血流恒定的原因。这可能是由一种交感神经机制引起的，该机制可保护眼睛免于过度灌注。
