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Purpose: To investigate the mechanism of gaze-evoked amaurosis., Case: A patient with an optic nerve tumor presented gaze-evoked amaurosis. A large central scotoma and constricted visual field were detected after shifting the gaze laterally. However, the patient did not notice this change until his fellow eye was occluded. Computed tomography/magnetic resonance imaging (CT/MRI) demonstrated a tubularly enlarged optic nerve extending for 1 cm from the eye ball, and the condition was judged to be optic nerve sheath meningioma. He underwent fluorescein fundus angiography twice, once during straight gaze and again during lateral gaze., Results: Manifestly decreased blood flow in the central retinal artery and filling defect in the optic nerve head were seen during lateral gaze., Conclusion: Forced lateral gaze may have increased the intra-optic nerve pressure at the optic nerve head and decreased the blood flow of the central retinal artery and peripapillary choroidal flow irrigating the optic nerve head.

Optic nerve meningiomas usually are seen in middle-aged and elderly women, and present as a slowly progressing axial proptosis and loss of vision. CT and MR imaging are the most valuable diagnostic tools to evaluate these tumors. This article reviews the MR imaging and CT characteristics of optic nerve sheath meningiomas and discusses features that may distinguish optic nerve sheath meningiomas from simulating lesions.

During the period 1985-95 we treated 5 girls and 13 boys with optic glioma associated with Type 1 neurofibromatosis (median age 3 years, range 2-10 years). 6 were treated with radiotherapy alone, 1 with surgery and radiation therapy and 1 with chemotherapy in order to postpone irradiation to an older age; 1 is being followed with no therapy. All children are alive, 2-10 years from diagnosis (mean follow-up time 5.4 years). 3 had improvement of vision following therapy and in 4 visual ability stabilized, including the child being followed without treatment. In 1 vision deteriorated despite therapy.

We retrospectively compared patients with NF1 with and without optic pathway gliomas (OPG) to determine the incidence and range of orbital developmental abnormalities and compared the incidence of OPG in African-Americans and whites. From cranial MR scans, we manually measured 14 orbital dimensions, compared them to published standards of Waitzman et al, calculated orbital volumes, and determined the presence or absence of volumetric symmetry (delta v) (delta v < or = 3 cm3 was considered to be symmetrical). We compared the results of orbital configurational assessment between patients with (group I) and those without OPG (group II). The study population comprised 58 patients, 24 boys, 18 African-American, and one Hispanic. Median age at imaging was 7 years (range 0.5-25.5 years). Fifty-eight percent had conformational abnormalities, 16 of whom had more than one abnormality (28%), the most frequent being increased intertemporal distance (n=10), increased lateral orbital distance (n=8), increased medial wall length (n=6), and decreased medial wall length (n=6). The increased intertemporal and lateral orbital distances may contribute to the appearance of hypertelorism. Only two patients had sphenoid wing hypoplasia. We found a high incidence of orbital dimensional abnormalities in the total population but more often saw multiple abnormalities in patients with OPG. However, no pattern of configurational abnormality emerged. OPG is less frequent in African-Americans. Orbital volumetric disparity seems to be independent of the presence of OPG.

A 54-year-old patient presented with amaurosis of the right eye that resulted from a dysontogenetic tumor of the right optic nerve. The tumor involved the intraorbital, intracanalicular and intracerebral portion of the right optic nerve, without involvement of the chiasm. Although the patient had refused further diagnostic surgical exploration, we show that it is possible to establish the diagnosis of choristoma of the optic nerve by means of modern neuroimaging techniques based on computed tomography and magnetic resonance imaging. It appears from neuroimaging that choristomata of the optic nerve and spinal cord lipomas represent different manifestations of the same type of tumor. The neuroimaging characteristics of both kinds of tumors are discussed.

For 11 years, a 50-year-old woman with euthyroid Graves' disease experienced intermittent exacerbations of her orbitopathy associated with a decline in visual acuity. On each occasion, treatment with systemic corticosteroids led to prompt recovery of vision. Upon referral for consideration for orbital decompressive surgery, computed tomography and magnetic resonance imaging scanning detected bilateral optic-nerve sheath meningiomas, as well as typical findings of Graves' disease. Orbital radiation therapy led to stabilization of visual function and orbital findings, eliminating the need for systemic steroids. To our knowledge, this is the first reported case of Graves' disease associated with bilateral optic nerve sheath meningiomas.

Purpose: To review the ways in which children with tumours affecting the anterior visual pathways present and to determine the extent of visual loss at presentation and the visual prognosis after treatment., Methods: A retrospective review of the 17 children (age 1-13 years at presentation) referred to a specialist paediatric oncology unit. Ten children had extrinsic tumours affecting the chiasmal area whilst 7 had intrinsic gliomas affecting the optic nerve and/or chiasm. Patients were followed up for up to 13 years (median 2 years)., Results: The children studied presented with a variety of symptoms including headaches, lethargy and growth failure. Despite the clinical finding of marked visual loss in several cases, visual failure was not prominent amongst the presenting symptoms. After surgical intervention and other treatment vision stabilised or improved; eyes with no perception of light for short periods could regain substantial vision., Conclusion: Children with progressive visual deterioration due to tumours do not readily verbalise their difficulty and may have profound loss at presentation. Standard clinical tests of vision will identify the extent of damage. Visual prognosis depends on the underlying pathology and length of history but prompt treatment may lead to substantial improvement in vision.