| 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) |
| A 60-year-old female and a 66-year-old male presented with post-traumatic pituitary apoplexy associated with clinically asymptomatic pituitary macroadenoma manifesting as severe visual disturbance that had not developed immediately after the head injury. skull radiography showed a unilateral linear occipital fracture. magnetic resonance imaging revealed pituitary tumor with dumbbell-shaped suprasellar extension and fresh intratumoral hemorrhage. Transsphenoidal surgery was performed in the first patient, and the visual disturbance subsided. decompressive craniectomy was performed in the second patient to treat brain contusion and part of the tumor was removed to decompress the optic nerves. The mechanism of post-traumatic pituitary apoplexy may occur as follows. The intrasellar part of the tumor is fixed by the bony structure forming the sella, and the suprasellar part is free to move, so a rotational force acting on the occipital region on one side will create a shearing strain between the intra- and suprasellar part of the tumor, resulting in pituitary apoplexy. Recovery of visual function, no matter how severely impaired, can be expected if an emergency operation is performed to decompress the optic nerves. Transsphenoidal surgery is the most advantageous procedure, as even partial removal of the tumor may be adequate to decompress the optic nerves in the acute stage. Staged transsphenoidal surgery is indicated to achieve total removal later. ( info) |
3/1975. Human psychophysical analysis of receptive field-like properties: V. Adaptation of stationary and moving windmill target characteristics to clinical populations. This paper describes the application of several key parameters of a windmill-shaped target (used in determinations of the psychophysical transient-like function) to clinical populations as a diagnostic tool for static perimetry. A technique for independently analyzing sustained- (Westheimer function) and transient-like retinally-based psychophysical responses is outlined, and stimulus characteristics, reliability and diagnostic potential of the tests are examined. Several particularly interesting clinical cases (one closure of a branch retinal arteriole) and two senile macular degeneration patients) are presented for illustrative purposes. In addition, a tentative 'working hypothesis' is presented as a basis for extensive future analysis of various clinical populations. ( info) |
4/1975. Cerebral polyopia with extrastriate quadrantanopia: report of a case with magnetic resonance documentation of V2/V3 cortical infarction. This is a case report of the occurrence of cerebral diplopia with right-side superior homonymous quadrantanopia in a young woman after chiropractic neck manipulation. magnetic resonance imaging confirmed an infarct in the left inferior V2/V3 (extrastriate) cortex. The characteristics of the diplopia are illustrated with the patient's drawings, and persisting abnormalities in perception are described in the area of the initial field defect after static (computed) visual field testing yielded normal results. ( info) |
| A 42-year-old woman with a 6-year history of diabetes insipidus and progressive hypersomnolence presented with visual loss. neuroimaging showed infiltration in the hypothalamus, the optic nerve, and the chiasm, as well as multiple lesions in other areas of the brain parenchyma. biopsy showed Langerhans cell histiocytosis. This is an unusual presentation of Langerhans cell histiocytosis, involving the visual pathways without manifestations outside of the central nervous system. The differential diagnosis and the magnetic resonance imaging findings will be discussed. ( info) |
6/1975. 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. ( info) |
7/1975. 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) |
8/1975. 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. ( info) |
9/1975. headache and bilateral visual loss in a young hypothyroid Indian man. We describe the exceptional association of Vogt-Koyanagi-Harada syndrome (VKHS) and hypothyroidism in a 29-year-old man of Indian heritage. VKHS is a rare uveomeningoencephalitic syndrome with probably autoimmune pathogenesis. Nontraumatic uveitis, aseptic meningoencephalitis, vitiligo, alopecia and poliosis are the leading clinical features of VKHS. The reported patient presented with bilateral visual loss and progressive frontal headache. VKHS was diagnosed due to characteristic ophthalmological findings and the diagnosis of aseptic meningitis. Due to the autoimmune pathogenesis, VKHS may be rarely associated with other autoimmune disorders. association of VKHS with autoimmune thyroid disease has been described in the literature in three patients. In the reported case hypothyroidism due to chronic autommune thyroiditis was diagnosed in association with VKHS. Routinely determination of thyroid function in patients with VKHS is recommended. ( info) |
10/1975. Treatment of paraneoplastic visual loss with intravenous immunoglobulin: report of 3 cases. BACKGROUND: Paraneoplastic visual loss is an autoimmune disorder believed to be caused by the remote effects of cancer on the retina (cancer-associated retinopathy [CAR]) or optic nerve. Both disorders may result in rapid and complete blindness. Spontaneous recovery of vision has not been reported. The serum of patients with CAR contains autoantibodies against recoverin, enolase, or unidentified retinal proteins. autopsy examination results of eyes of blind patients with CAR show complete absence of the retinal neurons involved in phototransduction. Corticosteroids and plasmapheresis are the only treatment options previously described. OBJECTIVE: To treat paraneoplastic visual loss. DESIGN AND methods: Three patients with metastatic cancer developed rapidly progressive loss of vision. The first patient had visual acuity of hand movements in each eye before intravenous immunoglobulin treatment. The second patient had visual acuity of light perception in both eyes. The third patient's visual acuity was 20/400 OD and 20/20 OS. Diagnostic tests included magnetic resonance imaging of the head and cytologic examination of the cerebrospinal fluid to exclude metastasis as the cause of visual loss and then an electroretinogram and serum tests for autoantibodies against retinal antigens to confirm the clinical diagnosis of CAR. patients 1 and 2 were treated with intravenous immunoglobulin (400 mg/kg per day) for 5 days; however, patient 3 received only a single dose due to adverse effects consisting of shortness of breath and itching. RESULTS: Within 24 hours of taking the first dose of intravenous immunoglobulin, the visual acuity of patient 1 improved from hand movements only in both eyes to 20/50 OD and 20/200 OS. After the third day of treatment, visual acuity in the left eye further improved to 20/40. Even with the improved acuity, Goldmann visual field perimetry results showed poor responses in both eyes. However, 2 weeks later there was marked visual field improvement, and visual acuity was maintained at 20/50 OD and 20/40 OS. Patient 2 had no improvements and continued to have light perception in both eyes. Patient 3 had improvements in visual field defects but remained 20/400 OD and 20/20 OS. CONCLUSION: Intravenous immunoglobulin may be another treatment option offered to patients with paraneoplastic visual loss in addition to corticosteroids or plasmapheresis because a review of the medical literature has shown no spontaneous improvements of visual function without treatment. ( info) |