Microvascular study of the retrolaminar optic nerve in man: The possible significance in anterior ischaemic optic neuropathy

Abstract

London SummaryThe morphology of the circle of Haller and Zinn and its variations were examined using methyl-methacrylate microvascular corrosion casting of human orbits obtained at post-mortem. It was found to be an elliptical microvascular anastomosis formed by branches of the medial and lateral para-optic short posterior ciliary arteries. The ellipse was divided into superior and inferior parts by the entry points of these branches into the eye, providing an altitudinal blood supply to the retrolam From 'Moorfields Eye Hospital, City Road, London. 2Institute of Ophthalmology,

Nonarteritic Anterior Ischemic Optic Neuropathy: An Update on Demographics, Clinical Presentation, Pathophysiology, Animal Models, Prognosis, and Treatment

“…This finding suggests that blood flow in NAION is compromised selectively in the paraoptic branches of the SPCAs, not in a generalized watershed distribution as the choroid is spared [21]. Supporting this theory of selective vascular insufficiency is that these branches of the SPCAs have upper and lower territories [22], which correlate with the altitudinal visual field defects commonly seen in NAION [21].…”

Ischemic model of optic nerve injury

“…The optic nerve vascular supply varies depending on the region. 10,[59][60][61][62][63][64][65] The superficial nerve fiber layer is supplied principally from the arterioles in the adjacent retina, which derive from the central retinal artery. The central retinal artery usually does not contribute to either the prelaminar or laminar region, although it may contribute minimally to the retrolaminar region.…”

Blood Supply of the Optic Nerve Head

“…The circle has recently been studied by plastic corrosion casts [17,[24][25][26] and described as giving branch es to the lamina cribrosa and peripapillary choroid as well as recurrent pial branches to the retrolaminar region. Olver et al [25,26] have called the circle 'perioptic nerve arteriolar anastomoses', consisting o f superior and inferior parts and showing marked interindividual and interocular variations in form, position and branches. In the lamina cribrosa, the blood vessels, 10-20 pm in diameter, lie in the fibrous septa and form a dense capillary plexus which makes this part of the ONH a highly vascular structure [27], The central reti nal artery does not supply this region.…”