Optic Nerve Impairment Research Articles

Visual dysfunction with basal skull tumours.

Early detection of visual loss caused by tumours of the base of the skull is accomplished by systematic tests of the pregeniculate optic pathway. Even when central acuity is relatively preserved, a relative afferent pupillary defect and reduced color perception yield evidence of impaired optic nerve conduction. Although confrontation tests of the visual fields are useful screening techniques, unexplained symptoms should be pursued with static and kinetic perimetry. Patterns of optic nerve and chiasmal field loss and atrophy of the dis or retinal nerve fibers are imprecise guides to the location of basal skull tumours. Regardless of the pattern of visual field defect, unexplained progressive loss of vision demands intensive neuroradiologic study of the basal cisterns and skull.

MRI in the diagnosis of multiple sclerosis

Objective It's a study of MRI diagnosis and differential diagnosis of multiple sclerosis (MS) in 49 cases. Methods 49 patients were diagnosed as MS of brain or/and spinal cord in the year of 1995 to 2002.All cases had clinical informations,including evoked potential.MR brain scan was done in 49 patients,and spinal cord scan was performed in 10 cases out of 49.Enhanced scan were done in 29 cases. A follow-up examination was done in 17 patients within 30 days after the initial study.Results Multiple brain lesions, located in peri-ventricular region, semi-elliptical center, cerebellum and brain stem, were revealed in 47 patients, MS plaques were speckle or patchy and the largest one was 2.2×5.0cm. Simple spinal Cord lesions involving at least 2 sections were revealed in 2 patients. Two cases were initially misdiagnosed as encephalities. Another case was defined as tumor because of the brainstem swelling and enhanced plaques. Optic nerve impairment was found in a case besides the brain lesions. Complicated brain and spinal Cord lesions were shown in 4 cases. Enhanced MRI scan was performed in 29 cases: non-enhanced lesions were revealed in 7 cases and lesions were enhanced in the rest 22. Mottling or plaque enhancement was presented in 20cases, while ring enhancement was presented in 2. Follow-up study showed the improvement in 17 cases.Conclusion Brain and spinal cord MS plaques can be demonstrated on MRI, while clinical manifestation is necessary for MRI diagnosis in atypical lesions. Serial study is helpful for differential diagnosis.

Trichloroethylene occupational exposure: elements for better prevention.

One hundred and eighty-eight workers occupationally exposed to trichloroethylene (TRI) were studied by physical examination, exposure parameters (measure of atmospheric TRI and urinary trichloroacetic acid (CA) and evaluation of personal factors (age, alcoholic and tobacco consumption). A statistical comparison (chi 2 test) of the frequency of the symptoms observed in the high- and low-exposure populations with an analysis of nonprofessional factors allowed us to distinguish different classes of symptoms. Those more likely linked with TRI exposure are trigeminal and optic nerve impairment, asthenia, headache and dizziness. An interaction between TRI exposure and alcohol intake on the occurrence of clinical liver impairment and degreaser flush is suggested.

Pupil Cycle Time in Optic Nerve Compression

We measured pupil cycle time before and after treatment in 11 patients with compressive optic nerve disease. Nine patients had chiasmal tumors and two had optic neuropathy of Grave's disease. Pupil cycle time before treatment was abnormal in at least one eye of all patients and in each case, pupil cycle time improved or worsened in accordance with the response to treatment of the patient's visual acuity and visual fields. This suggests that the pupil cycle time may be used as a simple objective office test for following up patients with impaired optic nerve conduction as the result of optic nerve compression. This information is similar to that gained from visual evoked response and may be used together with other objective clinical data such as disk pallor, nerve fiber loss, and relative afferent pupillary defect.