There is some evidence to suggest that thrombolysis has a beneficial effect in retinal vessel occlusion. However, there is concern that this therapeutic approach carries the risk of hemorrhage. Retrograde cannulation of the supraorbital arteries followed by irrigation with fibrinolytic agents may have the potential to minimize the risk of major complications. The study was conducted to investigate the anatomic and sonographic features of the supraorbital arteries. This cadaver dissection study was performed on the orbits of 12 cadaveric specimens. In each orbit, the supraorbital region was dissected, followed by cannulation of the supraorbital vessels and injection of ink. In six orbits, the orbital vessels and the distribution of the injected ink were investigated. Continuous-wave Doppler sonographic analysis of the supratrochlear and the supraorbital artery was performed in 40 orbits of 20 volunteers to measure the distance between the arteries and the midline. Cannulation with retrograde injection of ink was successfully performed in both the supratrochlear and the supraorbital arteries. The supratrochlear artery exhibited a more superficial course and a larger diameter than the supraorbital artery (1.08 +/- 0.19 mm vs. 0.86 +/- 0.19 mm SD). Dissection to the orbital apex revealed a spread of ink into the ophthalmic and the central retinal arteries. The average distance between the exit of the supratrochlear artery and the midline was found to be 16.4 +/- 1.7 mm (range, 13-20). The average distance between the exit of the supraorbital artery and the midline measured 26.5 +/- 2.6 mm (range, 23-35). The findings of this anatomic and sonographic study support the concept of percutaneous supraorbital vessel cannulation as a potential approach to thrombolysis in retinal vessel occlusion. The supratrochlear artery appears to provide the most reliable access route.