Optic Nerve: Developmental Anomalies and Common Tumors

Abstract

The optic nerve, also known as the second cranial nerve, is composed of axons that transmit visual information from the neurosensory retina to the visual cortex. There are multiple pathologies that can affect the human optic nerve. Congenital anomalies of the optic nerve include myelinated nerve fibers, morning glory syndrome, optic nerve choristoma, optic nerve coloboma, optic nerve hypoplasia and aplasia, and others. Tumors that can affect the optic nerve (ON) may occur primarily from within the nerve itself, from the surrounding optic nerve sheath (ONS), or secondarily spreading to the nerve from a distant site. They include optic pathway glioma, medulloepithelioma, oligodendroglioma, optic nerve sheath meningioma, and others. Here in this chapter, we will review the optic nerve anatomy, embryology, and physiology in addition to assessment of optic nerve function. Moreover, the clinical features, imaging findings, pathology, and treatment options of the most common and some rare congenital anomalies and primary tumors of the ON and sheath will be reviewed.

How Age and Gender Influence the Performance of Mach Bands

“…Results revealed that participants' Mach band effect becomes more pronounced as the optic nerve develops [11]. The optic nerve, also known as the second cranial nerve, is composed of axons that transmit visual information from the neurosensory retina to the visual cortex [12].…”

“…The age dependence on the hemispheric asymmetry may embed mechanisms that underlie the [13] behavioral and cognitive declination associated with age related neuropsychological diseases. It's inevitable that the sensitivity to light will decrease under the impact of age [12]. Therefore, with the increasing of age, the stimulation of receiving light will be reduced.…”

The Impact of Optic Nerve Disorders on Sleep Wake

“…They are a heterogenous group of disorders with multiple underlying mechanisms and may be sporadic or inherited. Notable conditions include coloboma (incomplete closure of the embryonic cleft), staphyloma (excavation of the peripapillary area), optic nerve choristoma (a congenital ocular or periocular tumour), tumours of the optic nerve and sheath (glioma, meningioma, medulloepithelioma, oligodendroglioma), morning glory syndrome (an embryological malformation of the optic disc) and myelinated nerve fibres (optic nerve fibres at the level of the optic disc are typically unmyelinated) (239,240). The following sections focus on OND relevant to my study population and systematic literature review, and as such describe optic nerve hypoplasia (ONH), septo-optic dysplasia (SOD), primary congenital glaucoma and buphthalmos, and optic neuropathy associated with retinopathy of prematurity (ROP).…”