Topography of the posterior arteries supplying the eye and relations to the optic nerve

The aim of the study was to investigate the arterial blood supply of the intraorbital part of the optic nerve.The location, course, length and diameter of the central retinal artery (CRA) and posterior ciliary arteries were studied in 19 adult white male preserved cadavers of between 35 and 75 years of age.In right eyes, the first branch of the intraorbital part of the ophthalmic artery was the CRA in 26.3% (5/19) and the CRA and medial posterior ciliary artery in 21% (4/19) of eyes. In left eyes, the first branch of the intraorbital part of the ophthalmic artery was the CRA in 47.4% (9/19) and the CRA and medial posterior ciliary artery in 26.3% (5/19) of eyes. The CRA was observed as a single branch in 57.9% and a trunk in 42.1% of right eyes, and as a single branch in 52.6% and a trunk in 47.3% of left eyes. The outer diameter of the CRA measured 0.6 +/- 0.1 mm (min-max 0.5-0.9 mm) in right eyes and 0.6 +/- 0.2 mm (min-max 0.4-0.9 mm) in left eyes. The CRA entered the optic nerve 7.5 +/- 2.2 mm (min-max 5.3-12.5 mm) behind the ocular bulb in right eyes and 7.4 +/- 2.3 mm (min-max 5.3-14.1 mm) behind it in left eyes, at its lower and medial side. The posterior ciliary arteries ran forward, divided into multiple branches and pierced the sclera close to the optic nerve medially, laterally or superiorly. The longitudinal capillaries ran between the optic nerve and the CRA antero-posteriorly, while the transverse capillaries surrounded the optic nerve. Collaterals from both the longitudinal and transverse capillaries joined to form a complicated capillary plexus.This article confirms the well known variability of the arterial circulation of the intraorbital part of the optic nerve. Better understanding of the arterial anatomy of the intraorbital part of the optic nerve should enable appropriate modification of surgical techniques.