Abstract
The in vivo hemodynamics of the ciliary process vasculature In the albino rabbit were studied with an Improved technique of Intraocular microendos-copy. The spreading pattern and velocity of the dye front has been observed in defined vessel segments following intracarotid Injection of Evans Blue.
In the anterior portion of the ciliary processes a “thoroughfare channel” (bypass) was found leading from the arteriolar tree directly Into the marginal venule bypassing the capillary network of the ciliary processes. This bypass is characterized by a higher blood flow velocity (1.5–3mm/sec) than was found for the capillary network (0.8–1 mm/sec). A stoppage of blood flow was observed in the capillary network at 45–50mmHg after step-wise elevation of intraocular pressure (IOP): blood flow was not stopped in the thoroughfare channel until IOP values of 55–60mmHg were reached. Intraarterial administration of vasoconstrictive agents could lead to a complete stoppage of blood flow in the capillary net whereas the marginal route often remained patent.