Spontaneous regression of optic gliomas: thirteen cases documented by serial neuroimaging.

OBJECTIVE: To demonstrate spontaneous regression of large, clinically symptomatic optic pathway gliomas in patients with and without neurofibromatosis type 1 (NF-1). METHODS: Patient cases were collected through surveys at 2 consecutive annual meetings of the North American Neuro-Ophthalmology Society (NANOS) and through requests on the NANOSNET Internet listserv. Serial documentation of tumor signal and size, using magnetic resonance imaging in 11 patients and computed tomography in 2 patients, was used to evaluate clinically symptomatic optic pathway gliomas. All tumors met radiologic criteria for the diagnosis of glioma and 4 patients had biopsy confirmation of their tumors. In 3 patients, some attempt at therapy had been made many years before regression occurred. In one of these, radiation treatment had been given 19 years before tumor regression, while in another, chemotherapy had been administered 5 years before signal changes in the tumor. In the third patient, minimal surgical debulking was performed 1 year before the tumor began to shrink. RESULTS: Spontaneous tumor shrinkage was noted in 12 patients. Eight patients did not have NF-1. In an additional patient without NF-1, a signal change within the tumor without associated shrinkage was detected. Tumor regression was associated with improvement in visual function in 10 of 13 patients, stability of function in 1, and deterioration in 2. CONCLUSIONS: Large, clinically symptomatic optic gliomas may undergo spontaneous regression. Regression was seen in patients with and without NF-1. Regression may manifest either as an overall shrinkage in tumor size, or as a signal change on magnetic resonance imaging. A variable degree of improvement in visual function may accompany regression. The possibility of spontaneous regression of an optic glioma should be considered in the planning of treatment of patients with these tumors.

Idiopathic intracranial hypertension: a case report with optic nerve histopathology.

We present the clinical and pathologic findings in an atypical case of idiopathic intracranial hypertension. A 51-year-old man had headaches, visual deterioration, papilloedema, and deafness. Neuroimaging was normal, and cerebrospinal fluid pressure monitoring confirmed increased intracranial pressure. The patient was treated with a ventriculo-peritoneal shunt. Histopathology revealed grossly atrophic optic nerves with almost complete axonal loss. The prelaminar portion of the optic nerves was thickened by gliosis and hyalinized capillaries, which have not been described previously.

Functional magnetic resonance imaging in the visual system.

Functional magnetic resonance imaging (fMRI) is a relatively new technique for measuring brain function during resting and activated conditions with good spatial and temporal resolution. Because of a robust and reproducible activation response to visual stimuli in the occipital cortex, many studies have been directed at visual function. The methodology has been refined progressively to allow more accurate detection of the small activation signal, and using computational mapping foci of cerebral activity have been displayed in a two-dimensional format. Several factors modifying the activation signal have been identified. fMRI has been used to define the retinotopic representation of areal boundaries and the localization of higher visual functions in the occipital cortex. Motion perception in area middle temporal (MT) is well-recognized, but eye movement studies are limited. The activated signal may have significant implications for our understanding of brain metabolism, but cerebral blood flow and oxygenation sensitive recordings after prolonged visual stimulation have given conflicting results. Clinically, fMRI can follow changes in cerebral activity during a progressive neurologic illness and measure responses to treatment. Neurosurgical planning in disorders such as epilepsy may be facilitated.

Clinical characteristics of microtropia--is microtropia a fixed phenomenon?

BACKGROUND/AIMS: Microtropia is believed to be a static condition, in which accepted achievable levels of vision are those of 6/12-6/9 maximum, with the inability to achieve "normal" levels of stereopsis. The aim of this paper was to present the results of treatment of 30 consecutively presenting primary microtropes, and assess their outcomes using a more active treatment strategy than that conventionally used. METHODS: Visual acuity, stereoacuity, fixation, and the presence of a central suppression scotoma were assessed in all patients before, during, and after treatment, which comprised wearing maximum refractive correction, and an occlusion strategy aiming for equal visual acuity. RESULTS: Equal visual acuity of 6/5 Snellen was achieved in 43% of the 30 patients, while 87% achieved 6/9 Snellen or better visual acuity in the microtropic eye. Stereoacuity of better than 60" of arc was attained in 37%, and foveal fixation on visuscopy in 55%. The treatment outcome was not affected by the patient's age, initial visual acuity, or the amount of anisometropia. A change in the patient's diagnosis was noted in 50%, with nine patients recovering completely. CONCLUSIONS: The results show that microtropia is not static. Equal 6/5 vision is attainable, as is high grade stereoacuity. The pattern of fixation may change during treatment and elimination of the microtropia is possible in some cases. There is a requirement for management protocols to be changed in order to treat this condition more effectively.

Recovery in microtropia: implications for aetiology and neurophysiology.

AIMS/BACKGROUND: The basis of binocular single vision in microtropia remains a matter of contention. This paper discusses the implications of recovery, in a group of primary microtropes following treatment, in relation to current concepts on the aetiology of the condition and proposed retinocortical correspondence. METHODS: Nine previously untreated primary microtropes whose condition resolved, were reviewed in detail to assess the patterns of change in retinal correspondence, uniocular fixation, stereoacuity, and visual acuity in response to treatment. RESULTS: Anomalous retinal correspondence (ARC), a central scotoma, reduced or absent stereoacuity, amblyopia, and uniocular eccentric fixation were present in all patients before treatment. Following treatment, all cases attained normal retinal correspondence (NRC), elimination of the central scotoma, stereo acuity levels of between 20 and 40 seconds of arc, 6/5 Snellen visual acuity in both eyes, and foveal fixation in both eyes. CONCLUSION: A hypothesis is put forward that for the patients described, a period of normal development is likely to have preceded the onset of microtropia, during which the retinocortical "foundations" for NRC were established. Precise pairing of foveo-foveal receptive fields was not abolished by the presence of amblyopia and a central scotoma, but this relation was temporarily suspended and binocular single vision was sustained via the neural substrate of paired receptive fields over a wide retinocortical area.

Computerized tomography angiography in isolated third nerve palsies.

OBJECT: The goal of this study was to assess the value of computerized tomography (CT) angiography as a diagnostic tool in isolated oculomotor nerve palsies. METHODS: One hundred consecutive patients who presented with an isolated third nerve palsy were examined by CT angiography. This procedure was followed by conventional cerebral angiography in most patients in whom a vascular abnormality was noted on the CT angiography. Thus, all patients whose symptoms were caused by a compressive aneurysm were identified. The remaining patients were observed clinically to exclude the possibility that a missed cerebral aneurysm caused the isolated third nerve palsy. Eighteen patients harbored a cerebral aneurysm responsible for causing the isolated third nerve palsy. Most of the remaining patients experienced some degree of spontaneous recovery. There was no clinical evidence to indicate that a case of compressive cerebral aneurysm causing the isolated third nerve palsy had been missed on CT angiography. CONCLUSIONS: Computerized tomography angiography is a reliable diagnostic tool for use in the assessment of patients with an isolated third nerve palsy; it can identify the minority of patients in whom conventional cerebral angiography may be required.

Papilloedema, a complication of progressive diaphyseal dysplasia: a series of three case reports.

BACKGROUND/AIMS: Progressive diaphyseal dysplasia (PDD) is a rare, autosomal dominant, osteosclerotic dysplasia affecting both endochondrally and intramembranously derived bones. Severely affected patients can develop progressive stenosis of the optic canals and compressive optic neuropathy. Although raised intracranial pressure (ICP) has been described in patients with PDD in whom visual loss has occurred, the elevation of ICP in those patients has been thought to be either non-contributory or only partially responsible for the accompanying visual loss. METHODS: Three cases were reviewed and the clinical and radiological characteristics are described here. RESULTS: All three patients had bilateral optic disc swelling with no radiological evidence of either compressive optic neuropathy or thrombosis of the intracranial venous sinuses. The aetiology of the disc swelling was proved to be papilloedema in the first two cases and was probably the dominant cause in the third case. CONCLUSION: The visual loss documented in at least two of the three patients reported appears to be solely attributable to raised ICP. Normalisation of the ICP has led to an improvement and stabilisation of the visual function in all three patients. Patients with PDD probably require periodic ophthalmic assessments.

Ischemic optic neuropathy and giant cell arteritis.

Acute loss of vision due to anterior ischemic optic neuropathy, both arteritic and nonarteritic, demands investigation and where indicated, treatment as an emergency. While advances continue in the understanding of the pathophysiology and investigation of arteritic anterior ischemic optic neuropathy, the nonarteritic form presents a major therapeutic problem, particularly in the absence of a satisfactory clinical technique for the measurement of optic nerve head blood flow. Because of steroid resistance and side effects of chronic steroid therapy in giant cell arteritis, alternative immunosuppressive agents are being explored. In nonarteritic ischemic optic neuropathy, etiologic factors such as activated protein C resistance raise the possibility of evaluation for prothrombotic states, while calcium channel blockers offer prospects for the relief of ischemic effects at the cellular level.

Homonymous quadrantanopia respecting the horizontal meridian. A feature of striate and extrastriate cortical disease.

It has been proposed that homonymous quadrantanopic visual field loss that respects the horizontal meridian is a pathognomonic sign of extrastriate cortical disease. However, two patients with this sign are reported--one with a rare striate and the other with an extrastriatal lesion of the visual cortex. It is therefore hypothesized that a homonymous quadrantanopia respecting the horizontal meridian may indicate striate and/or extrastriate cortical disease.

Acquired bilateral superior oblique palsy: a localising sign in the dorsal midbrain.

Bilateral superior oblique palsy is an uncommon ocular motility problem, the commonest cause being closed head trauma. Two cases, both adults, are presented in whom bilateral superior oblique palsy occurred as a result of neoplastic infiltration of the dorsal midbrain in the region of the anterior medullary velum. In the absence of a history of head trauma, the presence of an acquired bilateral superior oblique palsy is a definite sign of a single lesion in the region of the decussation of the trochlear nerves and appropriate imaging is indicated.

Neuro-ophthalmic features of carotid cavernous fistulas and their treatment by endoarterial balloon embolisation.

The neuro-ophthalmic features of 11 traumatic carotid cavernous fistulas and their successful occlusion by endoarterial balloon embolisation is reported. Significant improvement in all neuro-ophthalmic signs and symptoms occurred following treatment, however, ocular motility deficits persisted in 7 patients. All 11 fistulas were occluded and the patency of the internal carotid artery was preserved in 9 patients. Though the internal carotid artery was sacrificed in 2 patients there were no permanent sequelae. Transient complications of the procedure occurred in 2 patients.

Pituitary apoplexy and its effect on vision.

A series of 15 patients with a clinical diagnosis of pituitary apoplexy is reviewed. Clinical features are highlighted, with stress on the defects of visual function and ocular motility, and the associated endocrine abnormalities are described. Potential diagnostic errors and their significance are considered. The incidence of this complication in a large series of pituitary adenoma patients is measured, and the radiological and pathological findings are recorded. The results of treatment by surgery and/or radiotherapy and/or bromocriptine are assessed, particularly in relation to visual consequences, and compared with previous reports in the literature, which are reviewed.

Optochiasmal arachnoiditis following muslin wrapping of ruptured anterior communicating artery aneurysms.

Optochiasmal arachnoiditis has been reported following treatment of ruptured intracranial aneurysms, particularly arising from the anterior communicating artery. It has been suggested that the accompanying loss of vision is due to a muslin-induced optic neuropathy. This paper considers five cases of this condition; the response to steroid therapy was beneficial in three cases. A review of the literature is included. The arachnoiditis is considered to be due to an inflammatory response to muslin gauze placed close to the optic nerves and chiasm.

Hodgkin's disease at the optic chiasm.

In a case of visual loss due to infiltration of the optic chiasm by Hodgkin's lymphoma in a 44-year-old man the diagnosis was supported by histology of the optic chiasm, an axillary lymph node, and bone marrow at presentation. This appears to be only the third histologically proven reported case of Hodgkin's disease in this location, and the first diagnosed during life.

Ocular blood flow in unilateral carotid stenosis and hypotension.

Ocular blood flow was measured in the juxtapapillary choroid, retrolaminar optic nerve and ciliary body mesoderm using 14C-labelled iodoantipyrine with quantitative autoradiography in seven anesthetized baboons in an experimental model of cerebral and ocular ischemia induced by hemorrhagic hypotension following unilateral common carotid stenosis, with external carotid ligation. The eyes of seven baboons with unilateral common carotid occlusion were also examined histologically for evidence of structural changes. This autoradiographic method allowed measurement of blood flow in different ocular structures and a significant change was noted in the optic nerve of stenosed animals, without structural damage.

Rhino-orbital-cerebral mucormycosis--a clinico-pathological report of two cases.

Rhino-orbital-cerebral mucormycosis is an acute fungal infection of the oropharynx, paranasal sinuses, orbit and intracranial structures. It is rare, occurring mainly in diabetics in ketoacidosis. The clinical presentation is highly suggestive of the diagnosis. Current treatment has resulted in a greatly improved prognosis for survival and clinical awareness of this disease is important for early initiation of treatment with optimal effect. A clinico-pathological report of two cases is presented.

Glioma of the optic chiasm and its management.

The clinical features, radiological investigation and pathology of 9 cases of glioma of the optic chiasm are described and the place of radiotherapy in their management considered.

Recovery of vision following treatment of pituitary tumours: application of a new system of visual assessment.

The lack of a standard, quantitative method of assessing the degree of visual deficit hinders comparison of the results of the different methods available for treating visual failure due to pituitary tumour. This report describes a simple, semi-quantitative and precise approach and illustrates its use in 34 patients treated by transsphenoidal hypophysectomy and radiotherapy. Visual improvement occurred in 85 per cent of cases and no patient sustained deterioration of vision. The degree of pre-operative visual loss was scored at a mean of 51.4 per cent which reduced to a mean of 27.4 per cent at a minimum of twelve months' follow up. The factor that had the greatest influence on visual recovery was the degree of visual loss on presentation. It is therefore essential to be able to compare this variable before attempting to assess if outcome is different in a series treated by alternative methods.