Anatomy of the Human Optic Nerve: Structure and Function

Salazar, Juan; Ramírez, Ana I.; Hoz, Rosa de; Salobrar‐García, Elena; Rojas, Pilar; Fernández‐Albarral, José A.; López‐Cuenca, Inés; BlancaRojas,; Triviño, Alberto; Ramı́rez, José M.

doi:10.5772/intechopen.79827

Cited by 29 publications

(42 citation statements)

References 152 publications

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“…The optic nerve is customarily separated into four main regions. These are well described in reference [16] Fig. 1 in Chapter 2 page 13 and in reference [17] Fig.…”

Section: Introductionsupporting

confidence: 58%

Optic nerve microcirculation: Fluid flow and electrodiffusion

Zhu

Eisenberg

et al. 2021

Physics of Fluids

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Flows of water and various organic and inorganic molecules in the central nervous system are important in a wide range of biological and medical processes, as has recently become apparent (Nicholson et al. 2017 [1]). However, the exact mechanisms that drive these flows are often not known. Here we investigate the forces and flows in a tridomain model of the central nervous system. We use the experimental system of the optic nerve, investigated by the Harvard group Orkand et al [3,20] as a protype of the central nervous system in general. We construct a model and choose its parameters to fit the experimental data. Asymptotic analysis and numerical computation show the significant role of water in convective ion transport. The full model (including water) and the electro-diffusion model (excluding water) are compared in detail to show the main physiological consequences of the complex structure as viewed in our model. In the full model, convection due to water flow dominates inside the glial domain. This water flow in the glia contributes significantly to spatial buffering of potassium in the extracellular space. Convection in the extracellular domain does not contribute significantly to spatial buffering. Electrodiffusion is the dominant mechanism for flows confined to the extracellular domain.

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“…The optic nerve is customarily separated into four main regions. These are well described in reference [16] Fig. 1 in Chapter 2 page 13 and in reference [17] Fig.…”

Section: Introductionsupporting

confidence: 58%

Optic nerve microcirculation: Fluid flow and electrodiffusion

Zhu

Eisenberg

et al. 2021

Physics of Fluids

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“…The retinogeniculate pathway (RGVP) begins at the retina, passes through the optic nerve, the optic chiasm, and the optic tract, and finally connects to the lateral geniculate nucleus (LGN; Salazar et al, 2019 ; Purves et al, 2001 ). See Figure 1 for an anatomical overview.…”

Section: Introductionmentioning

confidence: 99%

Comparison of multiple tractography methods for reconstruction of the retinogeniculate visual pathway using diffusion MRI

Zhang

Xie

et al. 2021

Human Brain Mapping

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The retinogeniculate visual pathway (RGVP) conveys visual information from the retina to the lateral geniculate nucleus. The RGVP has four subdivisions, including two decussating and two nondecussating pathways that cannot be identified on conventional structural magnetic resonance imaging (MRI). Diffusion MRI tractography has the potential to trace these subdivisions and is increasingly used to study the RGVP. However, it is not yet known which fiber tracking strategy is most suitable for RGVP reconstruction. In this study, four tractography methods are compared, including constrained spherical deconvolution (CSD) based probabilistic (iFOD1) and deterministic (SD-Stream) methods, and multi-fiber (UKF-2T) and single-fiber (UKF-1T) unscented Kalman filter (UKF) methods. Experiments use diffusion MRI data from 57 subjects in the Human Connectome Project. The RGVP is identified using regions of interest created by two clinical experts. Quantitative anatomical measurements and expert anatomical judgment are used to assess the advantages and limitations of the four tractography methods. Overall, we conclude that UKF-2T and iFOD1 produce the best RGVP reconstruction results. The iFOD1 method can better quantitatively estimate the percentage of decussating fibers, while the UKF-2T method produces reconstructed RGVPs that are judged to better correspond to the known anatomy and have the highest spatial overlap across subjects.Overall, we find that it is challenging for current tractography methods to both accurately Jianzhong He and Fan Zhang are co-first-authors.

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“…The GCC may be superior to the circumpapillary RNFL since there is an enrichment of RGCs combined with retinotopic segregation. 62 Ganglion cell complex analysis has been compared to RNFL analysis using the special domain ocular coherence tomographer (SD-OCT), and it has been found that the two areas on the fundus have comparable diagnostic accuracy for glaucoma. 63 In a study by Kim et al, 64 it was found that macular GCC thickness was comparable to RNFL thickness in early, moderate and severe glaucoma.…”

Section: The Utility Of Gcc and Rnfl Evaluation In Glaucomamentioning

confidence: 99%

A review of ocular perfusion pressure and retinal thickness: A case for the role of systemic hypotension in glaucoma

Vawda

Munsamy

2021

African Vision and Eye Health

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Background: Ocular perfusion pressure (OPP) is defined as blood pressure (BP) minus intraocular pressure (IOP). Low OPP may result in decreased ocular blood flow (OBF) and oxygen to the optic nerve head (ONH) and retina.Aim: To review the role of systemic hypotension and similar conditions in OPP and its influence on retinal nerve fibre layer (RNFL) thickness and the ganglion cell complex (GCC).Method: A literature search was conducted using the following search terms: ‘systemic hypotension’; ‘glaucoma’; ‘retinal nerve fibre layer’; ‘optic nerve’; ‘ocular blood flow’ and ‘ocular perfusion pressure’.Results: The Los Angeles Eye Study and Barbados Eye Study found that decreased OPP and BP increased the risk of glaucoma development by up to six times. Reduced retinal perfusion with resultant thinning of the RNFL in conditions with a similar mechanism, such as obstructive sleep apnoea syndrome, has indicated the importance of reduced OPP in retinal thickness. In the absence of any study directly showing the effect of systemic hypotension on OPP and retinal thickness, a working hypothesis proposes that reduced BP with or without normal-to-raised IOP will reduce OPP. The reduced OPP and OBF in those with systemic hypotension may result in oxidative stress and hypoxia which may then cause retinal ganglion cell death and the resultant retinal thinning.Conclusion: The increased risk of glaucoma development and progression relating to decreased BP and OPP has been proven to be of importance. Monitoring patients with systemic hypotension and evaluating the macula, ONH RNFL and GCC thickness may alert clinicians to possible glaucomatous changes.

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Anatomy of the Human Optic Nerve: Structure and Function

Cited by 29 publications

References 152 publications

Optic nerve microcirculation: Fluid flow and electrodiffusion

Optic nerve microcirculation: Fluid flow and electrodiffusion

Comparison of multiple tractography methods for reconstruction of the retinogeniculate visual pathway using diffusion MRI

A review of ocular perfusion pressure and retinal thickness: A case for the role of systemic hypotension in glaucoma

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