| PURPOSE: To present a case of retrobulbar optic nerve and chiasm sarcoidosis that mimicked pseudotumor cerebri. methods: A 34-year-old, thin, black woman presented with transient visual obscurations, normal visual acuity, bilateral optic disk edema, and enlarged blind spots. Clinical, medical, and radiologic evaluations were consistent with pseudotumor cerebri. The patient improved while taking acetazolamide, but 6 months later her symptoms worsened. neuroimaging disclosed enhancement of the optic nerve and chiasm. RESULTS: Despite administration of intravenous corticosteroids, the patient's vision worsened. Bilateral optic nerve sheath fenestrations were performed, and pathology disclosed sarcoidosis. CONCLUSION: sarcoidosis of the optic nerves and chiasm may mimic pseudotumor cerebri. ( info) |
| 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. ( info) |
| The authors present a first case of cysticercosis in the optic canal in a fifteen-year-old female patient. cysticercosis of the optic nerve is rare. A cyst in the optic canal, beneath the sheath of the optic nerve, has never been reported. The patient presented with rapidly diminishing vision in the left eye, headache and papillitis. A magnetic resonance imaging revealed a cystic lesion at the entrance of the optic canal. Surgery performed was a transcranial orbitotomy which included deroofing of the optic canal and removal of the cyst from under the sheath of the optic nerve. The cyst proved to be cysticercus histopathologically. The outcome was a remarkable visual recovery. ( info) |
4/936. Optic disc topographic changes post-trabeculectomy visualized by anaglyphs. BACKGROUND: publications on changes of optic disc topography usually illustrate their findings with two-dimensional images. methods: With the introduction of computerized imaging, anaglyphs of stereo images can be produced for illustrations. Anaglyphs are viewed three-dimensionally with red-green spectacles that are included in refraction sets and are normally used to assess phoria. An anaglyph of progressive, glaucomatous progression is included to demonstrate the method, along with conventional colour images. RESULTS: We present two cases of severely altered optic disc topography post-trabeculectomy and illustrate these cases with anaglyphs that can be viewed three-dimensionally. CONCLUSION: Three-dimensional viewing of illustrations assists with the visualization, perception and interpretation of optic disc changes. ( info) |
5/936. Cerebral metastasis presenting with altitudinal field defect. A 75-year-old man presented with a unilateral inferior altitudinal visual field defect and a history of weight loss and night sweats. The acuity in the affected eye was 20/200, otherwise his ocular examination was normal. neuroimaging demonstrated a post-fixed chiasm, with a frontal metastasis compressing the intracerebral portion of the optic nerve. A chest x-ray showed classical cannon ball lesions, secondary to malignant melanoma. This is the first case report of an intracerebral tumor producing an inferior altitudinal field defect. ( info) |
6/936. Acquired convergence-evoked pendular nystagmus in multiple sclerosis. Nystagmus seen only with convergence is unusual. We describe four cases of acquired convergence-evoked pendular nystagmus in patients with multiple sclerosis. The nystagmus was horizontal and asymmetric in all patients. eye movement recordings in one subject showed a conjugate rather than a convergent-divergent relationship of the phase of movement between the two eyes. All patients had evidence of optic neuropathy and cerebellar dysfunction. Occlusion of either eye during fixation of near targets led to divergent drift of the covered eye and a decrease in nystagmus. Intravenous scopolamine reduced nystagmus in one patient. Base-in prisms alleviated symptoms of oscillopsia at near and improving reading visual acuity. Convergence-evoked pendular nystagmus may be more common than currently appreciated, particularly among patients with multiple sclerosis. ( info) |
7/936. 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. ( info) |
8/936. Surgical management of lesions affecting the anterior optic pathways. Although benign neoplasms are the most common lesions of the anterior visual pathways that lend themselves to a combined neurosurgical and ophthalmic surgical treatment, malignant neoplasms, infections (especially fungal), and vascular lesions are also sometimes treated via a combined approach. Recent advances in the field of skull base surgery have made it possible to treat complicated lesions in precarious locations with increasing margins of safety and decreasing morbidity. The role of the neurosurgeon in managing selected patients with lesions of the anterior a visual pathway should not be underestimated. ( info) |
| Two patients with adolescent onset glaucoma associated with sturge-weber syndrome have been presented. Both patients were successfully treated with ab externo trabeculectomy. This procedure is suggested as an additional means for controlling the late onset glaucoma associated with the syndrome without provoking additional complications or deterioration. Early treatment is emphasized before the irreversible changes of chronic glaucoma become manifest. ( info) |
| A five-year-old boy presented with tuberculous meningitis and subsequently developed amaurosis with optochiasmatic arachnoiditis (OCA) late in the convalescent stage of the illness. The visual evoked cortical potentials were correlated with the decreased and improved postoperative acuity. The diagnosis and classification of OCA have been discussed with emphasis given to prompt neurosurgical treatment. ( info) |