Reitsamer Herbert A, Kiel Jeffrey W
Department of Physiology, University of Vienna Medical School, Vienna, Austria.
Invest Ophthalmol Vis Sci. 2003 Sep;44(9):3967-71. doi: 10.1167/iovs.03-0088.
To determine the relationship between ciliary blood flow and aqueous flow by changing the mean arterial pressure (MAP) mechanically under controlled conditions in an animal model.
In anesthetized rabbits, MAP and intraocular pressure (IOP) were measured by direct cannulation. MAP was controlled with occluders placed on the aorta and vena cava. In group 1 (n = 22), aqueous flow was measured by fluorophotometry. In group 2 (n = 21), ciliary blood flow was measured by laser Doppler flowmetry. In separate subgroups, measurements were made for 60 minutes at the control MAP of 70 mm Hg and for an additional 60 minutes at target MAPs of 80, 55, or 40 mm Hg.
The target MAPs achieved perfusion pressures (MAP - IOP) of 33.6 +/- 1.0, 43.5 +/- 0.7, 51.9 +/- 0.6, and 65.2 +/- 0.9 mm Hg. Ciliary blood flow was unaffected by increased perfusion pressure, but decreased progressively as perfusion pressure was lowered. Aqueous flow decreased only at the lowest perfusion pressure.
Under control conditions in anesthetized rabbits, aqueous production is independent of ciliary blood flow until ciliary blood flow declines below 74% of control. At ciliary blood flow below this critical level, aqueous production is blood flow dependent.
在动物模型的可控条件下，通过机械改变平均动脉压（MAP）来确定睫状体血流与房水流量之间的关系。
对麻醉的兔子，通过直接插管测量MAP和眼压（IOP）。用置于主动脉和腔静脉上的封堵器控制MAP。在第1组（n = 22）中，通过荧光光度法测量房水流量。在第2组（n = 21）中，通过激光多普勒血流仪测量睫状体血流。在不同的亚组中，在70 mmHg的对照MAP下测量60分钟，并在80、55或40 mmHg的目标MAP下再测量60分钟。
目标MAP实现的灌注压（MAP - IOP）分别为33.6±1.0、43.5±0.7、51.9±0.6和65.2±0.9 mmHg。睫状体血流不受灌注压升高的影响，但随着灌注压降低而逐渐减少。房水流量仅在最低灌注压时降低。
在麻醉兔子的可控条件下，直至睫状体血流降至对照值的74%以下，房水生成与睫状体血流无关。在睫状体血流低于此临界水平时，房水生成依赖于血流。
