Abstract
The rat optic nerve head (ONH) is a segment about 250 μm in length extending from the funnel-shaped region where the optic nerve fibres (retinal ganglion cell axons, RGC) converge on the optic disc rostrally to the transition to the optic nerve (ON) caudally. The ONH has a characteristic kidney shape, some 500 μm wide and 300 μm dorsoventrally, with the ‘hilus’ of the kidney always at the midventral pole and occupied by two large vessels, the ophthalmic vein dorsally and the ophthalmic artery ventral to this. For complete orientation of the cross sections in space, therefore, it is only necessary to mark the medial and lateral edges at the time when the tissue is removed. The rat ONH contains only three tissue components—totally unmyelinated RGC axons, specialised astrocytes, and the endothelial cells of the microvessels which penetrate from the ventral to the dorsal surfaces. Unlike the human lamina cribrosa, there is no connective tissue, collagenous strengthening of the perivascular spaces. Since raised intraocular pressure causes RGC axon damage in the ONH of the rat, this indicates that the injurious effects of pressure transduction can be exerted in the absence of a connective tissue lamina cribrosa. Both structural integrity and function of axon are supported by astrocytes and microvessels. Astrocytes play the key role in the interactions of axons and microvessels. Rat ONH is a good model to understand the relationship of axon, astrocyte and microvessel in human lamina cribrosa (Fig. 19.1).
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Dai C, Khaw PT, Yin ZQ, Li D, Raisman G, Li Y. Structural basis of glaucoma: the fortified astrocytes of the optic nerve head are the target of raised intraocular pressure. Glia. 2012;60:13–28.
Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006;90:262–7.
Hernandez MR, Miao H, Lukas T. Astrocytes in glaucomatous optic neuropathy. Prog Brain Res. 2008;173:353–73.
Morrison JC, Cepurna Ying Guo WO, Johnson EC. Pathophysiology of human glaucomatous optic nerve damage: insights from rodent models of glaucoma. Exp Eye Res. 2011;93:156–64.
Morrison JC, Johnson EC, Cepurna W, Jia L. Understanding mechanisms of pressure-induced optic nerve damage. Prog Retin Eye Res. 2005;24:217–40.
Quigley HA, Addicks EM. Regional differences in the structure of the lamina cribrosa and their relation to glaucomatous optic nerve damage. Arch Ophthalmol. 1981;99:137–43.
Quigley HA, Addicks EM, Green WR. Optic nerve damage in human glaucoma. III. Quantitative correlation of nerve fiber loss and visual field defect in glaucoma, ischemic neuropathy, papilledema, and toxic neuropathy. Arch Ophthalmol. 1982;100:135–46.
Quigley HA, Addicks EM, Green WR, Maumenee AE. Optic nerve damage in human glaucoma. II. The site of injury and susceptibility to damage. Arch Ophthalmol. 1981;99:635–49.
Soto I, Oglesby E, Buckingham BP, Son JL, Roberson ED, Steele MR, et al. Retinal ganglion cells downregulate gene expression and lose their axons within the optic nerve head in a mouse glaucoma model. J Neurosci. 2008;28:548–61.
Jonas JB, Wang N, Nangia V. Ocular perfusion pressure vs estimated trans-lamina cribrosa pressure difference in glaucoma: The Central India Eye and Medical Study (An American Ophthalmological Society Thesis). Trans Am Ophthalmol Soc. 2015;113:T61–T613.
Jonas JB, Wang N, Wang YX, You QS, Yang D, Xie X, et al. Subfoveal choroidal thickness and cerebrospinal fluid pressure: the Beijing Eye Study 2011. Invest Ophthalmol Vis Sci. 2014;55:1292–8.
Jonas JB, Wang N, Yang D. Translamina cribrosa pressure difference as potential element in the pathogenesis of glaucomatous optic neuropathy. Asia-Pacific J Ophthalmol. 2016;5:5–10.
Zhang Z, Liu D, Jonas JB, Wu S, Kwong JM, Zhang J, et al. Axonal transport in the rat optic nerve following short-term reduction in cerebrospinal fluid pressure or elevation in intraocular pressure. Invest Ophthalmol Vis Sci. 2015;56:4257–66.
Zhang Z, Wu S, Jonas JB, Zhang J, Liu K, Lu Q, et al. Dynein, kinesin and morphological changes in optic nerve axons in a rat model with cerebrospinal fluid pressure reduction: the Beijing Intracranial and Intraocular Pressure (iCOP) study. Acta Ophthalmol. 2016;94:266–75.
Dai C, Li DQ, Li Y, Raisman G, Yin ZQ. [Studies on glial isomerization of lamina cribrosa in rat], [Zhonghua yan ke za zhi]. Chinese J Ophthalmol. 2013;49:723–8.
Acknowledgments
The text and figures of this manuscript have appeared previously in our own work: Dai C, Khaw PT, Yin ZQ, Li D, Raisman G, Li Y. Structural basis of glaucoma: the fortified astrocytes of the optic nerve head are the target of raised intraocular pressure. Glia. 2012;60(1):13–28 [1]. They have been used with permission and edited for this chapter.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer Nature Singapore Pte Ltd.
About this chapter
Cite this chapter
Dai, C., Raisman, G., Li, Y. (2019). Fortified Astrocyte: The Target of Pathological Intraocular Hypertension. In: Wang, N. (eds) Intraocular and Intracranial Pressure Gradient in Glaucoma. Advances in Visual Science and Eye Diseases, vol 1. Springer, Singapore. https://doi.org/10.1007/978-981-13-2137-5_19
Download citation
DOI: https://doi.org/10.1007/978-981-13-2137-5_19
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-13-2136-8
Online ISBN: 978-981-13-2137-5
eBook Packages: MedicineMedicine (R0)