Fig. 3.

Schematic representation of competing mechanisms influencing ocular circulation. Blood flow is driven by the difference between arterial and venous pressures, impeded by external pressures acting upon the vasculature (e.g. intraocular pressure, cerebrospinal fluid pressure and intracranial pressure), and modulated by vascular regulation. In vivo measurements are the result of a complex interaction among these mechanisms. Abbreviations: OA: Ophthalmic Artery; OV: Ophthalmic Vein; CRA: Central Retinal Artery; CRV: Central Retinal Vein; PCA: Posterior Ciliary Artery.