Microvasculature of the human optic nerve.

PURPOSE: Methyl methacrylate vascular corrosion casting techniques were used to examine the normal anterior optic nerve microvasculature in 18 human eye bank eyes. METHODS: Selective cannulation of the central retinal artery, the short posterior ciliary arteries, or both, allowed the methyl methacrylate to be injected into the anterior optic nerve circulation. Preflushing with tissue plasminogen activator greatly enhanced the filling of the fine microvasculature by dissolving the intraluminal clots. RESULTS: The superficial nerve fiber layer of the optic nerve received its primary blood supply from the central retinal artery. In 11 of 13 eyes injected with methyl methacrylate through the short posterior ciliary arteries, there was a perineural, circular arterial anastomosis (circle of Zinn-Haller) at the scleral level. Branches from this circle penetrated the optic nerve to supply the prelaminar and laminar regions and the peripapillary choroid. In the two eyes without this arterial circle, direct branches from the short posterior ciliary arteries supplied the anterior optic nerve. The venous drainage of the anterior optic nerve was almost entirely through the central retinal vein and its tributaries. CONCLUSIONS: This study demonstrates that the main arterial vascular supply to the anterior optic nerve is from the short posterior ciliary arteries. The contribution of the peripapillary choroid to the anterior optic nerve is minimal in comparison to the direct contribution from the short posterior ciliary arteries.

Embolization of neurosurgical lesions involving the ophthalmic artery.

OBJECTIVE: A number of anteriorly located cranial base and extracranial lesions receive their vascular supply wholly or in part from the ophthalmic artery, and embolization of the ophthalmic artery can be helpful in the management of these lesions, either as the primary treatment or as an adjunct to surgery. We present situations in which the embolization of lesions involving the ophthalmic artery was performed to effect a partial or total cure of the lesion. METHODS: Twelve patients underwent a total of 15 embolization attempts on lesions involving the ophthalmic artery. Four patients had arteriovenous malformations of the orbit, four had dural arteriovenous fistulae, two had orbital meningiomas, one had a planum sphenoidale meningioma, and one had a juvenile nasal angiofibroma. In each case, a Tracker No. 18 microcatheter (Target Therapeutics, Inc., Fremont, CA) was navigated into the ophthalmic artery using a steerable guidewire and digital road mapping. Embolic agents included polyvinyl alcohol particles ranging from 350 to 1500 microm in diameter, 2-mm platinum microcoils, and n-butyl-cyanoacrylate. In 12 of 15 cases, lidocaine and amytal provocation tests were conducted before any attempt at embolization to assess the role of the ophthalmic artery in vision. RESULTS: Embolization was successfully performed in the 14 situations in which it was attempted. Positive results of two lidocaine/amytal tests were noted. In one case, embolization was not attempted. In the other case, a larger caliber embolic agent (2-mm platinum coils) was used. A single transient decrease in visual acuity lasting 4 days was the only embolization-related complication. CONCLUSION: Proper case selection, judicious use of embolic agents, and use of provocative testing can result in safe embolization of lesions supplied by the ophthalmic artery.