INTRODUCTION Ethambutol is used in the treatment of tuberculosis, which is still prevalent in Southeast Asia, and can be associated with permanent visual loss. We report 3 cases which presented with bitemporal hemianopia. CLINICAL PICTURE Three patients with ethambutol-associated toxic optic neuropathy are described. All 3 patients had loss of central visual acuity, colour vision (Ishihara) a...

Introduction The structure of the optic chiasm varies widely between the primate and the rodent [1]. The fiber architecture of the marmoset (Callithrix jacchus), a New World primate, is close to that of humans [2]; therefore, the marmoset has been used to study the development of the optic chiasm. Further, the body weight of the marmoset (around 300 g) is similar to that of the rat, but its bra...

Central nervous system (CNS) lesions, mainly involving the meninges, are found in up to 16% of autopsy studies of patients with known sarcoidosis [1]. Primary CNS sarcoid granuloma without systemic disease is seen in only about 5% of patients [2]. The characteristic MRI appearance of chiasmal sarcoidosis is peripheral contrast enhancement resulting from meningeal involvement. We report a rare c...

Optx2, a member of the sine oculis-Six family of homeobox genes, is first expressed in the anterior neural plate of the mouse embryo, and subsequently in the optic vesicle and ventral forebrain. During later development, expression is further restricted to precursors of the neural retina, optic chiasm, adenohypophysis and neurohypophysis. In the adult mouse retina, Optx2 mRNA is found in cells ...

Objective. Meningiomas are benign primary meningeal tumors and are seen rare in children and adolescents. Clinical Presentation and Intervention. A 15-year-old Turkish boy reported a 1-month history of headache and blurred vision in both eyes. His visual acuity was 0.3 in both eyes with papilledema. Magnetic resonance imaging showed a 77 × 97 × 77 mm intracranial-extra-axial frontal lesion whic...

The carbocyanine dye, DiI, has been used to study the retinal origin of the uncrossed retinofugal component of the mouse and to show the course taken by these fibres through the optic nerve and chiasm during development. Optic axons first arrive at the chiasm at embryonic day 13 (E13) but do not cross the midline until E14. After this stage, fibres taking an uncrossed course can be selectively ...

During development, the axons of retinal ganglion cell (RGC) neurons must decide whether to cross or avoid the midline at the optic chiasm to project to targets on both sides of the brain. By combining genetic analyses with in vitro assays, we show that neuropilin 1 (NRP1) promotes contralateral RGC projection in mammals. Unexpectedly, the NRP1 ligand involved is not an axon guidance cue of the...

Gliomas are the most common tumors in the optic nerve, chiasmal, and hypothalamic regions of the central nervous system (CNS). As such, they are the focus of this chapter. For completeness, the less common tumors of these regions—meningiomas and craniopharyngiomas—are also covered. Germ cell tumors can also occur in this region but are discussed in Chapter 7. GLIOMAS Gliomas that affect the opt...

CLINICAL CASE The case of a three-year-old patient with neurofibromatosis type I is presented. Ophthalmologic evaluation revealed, by means of magnetic resonance imaging, the presence of a silent glioma in the optic nerve of the left eye. DISCUSSION Neurofibromatosis-1 can present in multiple ways to the ophthalmologist, with a glioma of the optic nerve being one of the most frequent central ...