1/623. carbon monoxide poisoning causes optic neuropathy.PURPOSE: To describe the electrophysiological and psychophysical effects of carbon monoxide (CO) poisoning on visual function. methods: Three patients are presented who suffered CO poisoning, two due to suicide attempts and one in the course of a road traffic accident. After a full ocular examination, Goldmann visual fields, flash and pattern visual evoked potentials (VEPs) and flash and pattern electroretinograms (ERGs) were tested. RESULTS: electrophysiology showed reduced or absent N95 components of the pattern ERG and delayed, reduced VEPs. A positive-negative-positive (PNP) VEP waveform was seen in two cases. In one case, where presentation occurred at an early stage, visual and electrophysiological function was improved with hydroxycobalamine. CONCLUSIONS: The combination of ERG and VEP findings suggest that CO poisoning can cause a toxic optic neuropathy that may have a similar aetiological mechanism to that in tobacco amblyopia. Early treatment with hydroxycobalamine may be of some benefit.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
2/623. Surgical removal of a free floating cyst of the iris pigment epithelium causing disturbing visual symptoms.Pigmented cysts in the anterior chamber, fixed or free floating, are considered to be unusual but not very infrequent. However, most of these cases usually do not need any treatment other than a periodic observation. We report the surgical removal of an iris pigment epithelial cyst floating freely in the anterior chamber. The reason for surgical removal was, disturbance in near vision being caused by movement of the cyst across the visual axis. This specific symptom of disturbed near vision, to the best of our knowledge, is a rare indication for surgery that has not been pointed out earlier. Histopathological confirmation of the clinical diagnosis was also obtained.- - - - - - - - - - ranking = 4keywords = ms (Clic here for more details about this article) |
3/623. Compression of the visual pathway by anterior cerebral artery aneurysm.Visual failure is an uncommon presenting symptom of an intracranial aneurysm. It is even more uncommon in aneurysms arising from the anterior cerebral artery (ACA). We presented 2 patients with an aneurysm of the A1 segment of the anterior cerebral artery causing visual field defects. One patient presented with a complete homonymous hemianopia due to compression of the optic tract by a giant aneurysm of the proximal left A1 segment. The second patient had an almost complete unilateral anopia caused by compression of the optic nerve and chiasm by an aneurysm of the distal part of the A1 segment with a small chiasmatic hemorrhage and ventricular rupture.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
4/623. Creutzfeldt-Jakob disease presenting with visual blurring, diplopia and visual loss: Heidenhain's variant.Focal electroencephalographic abnormalities as described in Heidenhain's variant of Creutzfeldt-Jakob disease are uncommon. We report a 73-year-old male presenting with visual symptoms, right hemianopia and rapidly progressive dementia. myoclonus was synchronous with generalised periodic epileptiform discharges on electroencephalography (EEG). In addition, there were periodic focal sharp waves at the left occipital region. diffusion-weighted magnetic resonance brain images showed slightly increased signal intensity in the occipital parasagittal area, left more than right. 14-3-3 protein was detected in the cerebrospinal fluid. The patient died within 5 months of presentation.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
5/623. Spontaneous intracranial hypotension.PURPOSE: To describe a patient with classic presentation of spontaneous intracranial hypotension and subsequent improvement with targeted epidural blood patch. methods: Report of one case and review of the literature. RESULTS: Examination of cerebrospinal fluid after lumbar puncture disclosed a reduced opening pressure, an increased level of protein, and lymphocytic pleocytosis. magnetic resonance imaging of the brain with gadolinium showed diffuse enhancement of the pachymeninges, no evidence of leptomeningeal enhancement, and chronic subdural fluid collection. Radionuclide cisternography demonstrated reduced activity over the cerebral convexities, early accumulation of radiotracer in the urinary bladder, and direct evidence of leakage at the cervicothoracic junction (C7-T1). Clinical, laboratory, and radiologic features were consistent with the diagnosis of spontaneous intracranial hypotension. Therapy with a targeted epidural blood patch resulted in the rapid resolution of symptoms. CONCLUSIONS: In this report, we describe a classic case of spontaneous intracranial hypotension in a 63-year-old man with an initial presentation of postural headaches, blurred vision, pain in the left eye, diplopia on left gaze, and neck soreness.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
6/623. The automatic occluder, a new concept.An electro-mechanical occluder is described for use in treating problems of binocular vision. A number of methods of achieving the automatic occluder goal are reviewed. Early results of clinical studies now in progress indicate that the "autocluder" has unique clinical usefulness.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
7/623. On the visual disturbances associated with massive basal aneurysms.When massive basal aneurysms compromise the anterior visual pathways the resulting disturbances of vision are diverse and a firm clinical diagnosis is difficult. Because of the rarity of the condition, a critical analysis of the visual defects was made in five personally studied patients with large anterior basal aneurysms in an effort to clarify the clinical features of the disorder. These observations were related to those reported in larger series of patients by Jefferson and Bull. This study gives support to the opinion that the commonest visual defect seen with massive basal aneurysms is impairment of visual acuity, followed next in frequency by bitemporal hemianopia, and then by junction scotoma.- - - - - - - - - - ranking = 7keywords = ms (Clic here for more details about this article) |
8/623. The measurement of spatial contrast sensitivity in cases of blurred vision associated with cerebral lesions.Thirty-five patients with known cerebral lesions complained of recently acquired blurred vision. None of them had evident oculomotor or pupillary abnormalities, and each had intact central fields and normal visual acuity by conventional standards. Examination of spatial contrast sensitivity was carried out with sinusoidal grating patterns, by determining the minimum contrast between alternate light and dark bars required to distinguish the pattern from a homogeneous field. This was done at each of several spatial frequencies which were established by varying the width of the bars and hence the coarseness of the pattern. The contrast sensitivities were plotted as "visuograms" which, by analogy to audiograms, record the sensitivities in comparison to normal standards. Of the 35 patients, most showed significant losses, amounting to greater than 50 per cent elevation of contrast thresholds. Eighteen showed high frequency losses; 11 had uniform reductions over the entire visible spatial frequency range and 6 had selective frequency losses in the intermediate frequency ranges. These defects in spatial contrast sensitivity, which were not predictable from standard acuity scores, indicate that the visual symptoms in our patients may have been caused by damage to frequency-selective neural elements in the central visual systems. The method may be used to advantage in clinical investigations as well as in physiological investigations of the functional pathways subserving central vision.- - - - - - - - - - ranking = 4keywords = ms (Clic here for more details about this article) |
9/623. The somatic component of schizophrenia: a dissociation of the goals of visual attention and bifoveal fixation?The presence of disorders of eye movements is today regarded as 'the strongest candidate for a genetically transmitted biological trait marker of schizophrenic disorders' (1). The present study is based on the experience, rather than the behaviour, of one patient in a search for a method of objectifying his visual problems. This method was found to be a simple test, which demonstrates a disturbance of fixation: while one eye accommodated on the figure without vergence, the other, vergent, eye fused with the image of the related background. The disorder had been misdiagnosed as 'exophoria' in conventional ophthalmological examinations, because prevailing ophthalmological theory accepts only one mode of vision; according to the most recent researches, however, it is necessary to distinguish two complementary modes of vision--one for panorama and one for detail--which differ in their coordination of vergence and accommodation. This new bimodal theory of vision--presented here for the first time--made it possible to understand the cause of the disorder as a substitution of sighting for fixation, due either to a disinhibition of panorama vision during fixation vision, or to an interchange of ipsilateral temporal and contralateral nasal projections from the retina, both associated with a fixation disparity. After correction of the patient's fixation disparity according to an unusual method, the dissociation of the visual goals was remedied and the mental disturbances of the patient vanished.- - - - - - - - - - ranking = 1keywords = ms (Clic here for more details about this article) |
10/623. A model for the assessment and management of children with multiple disabilities.Children with multiple disabilities present complex management problems, both for their families and for the professionals involved in their care. For any one child, the list of functional and medical problems that need to be addressed is frequently reflected in an even longer list of involved professionals, leading to conflicting advice and problems in co-ordination of care. A hierarchical model for assessment and management is proposed, which highlights the interdependency of apparently different areas of functioning. The model aims to assist both parents and professionals in determining priorities, to improve interdisciplinary working, and to underpin staff training. Illustrative case studies indicate the importance of resolving issues in areas such as visual functioning, positioning and nutrition before integrated functions such as communication skills can be addressed successfully.- - - - - - - - - - ranking = 4keywords = ms (Clic here for more details about this article) |
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