Clinical study of indirect optic nerve injury caused by motor vehicle accident / 中华急诊医学杂志

Objective To evaluate the curative effects of intravenous methylprednisolone (IVMP) during the conservative management for patients with indirect optic nerve injury (ONI),and to analyze the benefits of visual evoked potential (VEP) monitoring in prognosis assessment.Methods Among the 253 patients with cranial-facial injury,108 sufferred from optic nerve injury including 89 cases without optic nerve decompression treatment.These 89 patients were randomly divided into:group A,in which patients were given methylprednisolone intravenously for 7 days; and group B,in which patients without methylprednisolone treatment.The extent of and time required for eyesight recovery were recorded.VEP measurement was carried out in all cases.Results No differences in gender,age and BMI (Body Mass Index,all P ＞ 0.05) were observed.The incidence of ONI was higher in patients with motorcycle accident than that in those with car accident (P ＜0.01).In the motorcycle accidents,casualties wearing a helmet had lower incidence of ONI (P ＜ 0.01).Patients treated with methylprednisolone had a shorter recovery time (P ＜ 0.01) from blindness,however there was no difference in long-term outcome between group A and B.In patients with visual improvement in the “ non-extinguished” group,the amplitude and latency of the P wave of VEP were markedly ameliorated after the treatments (P ＜ 0.01).Conclusions Most of the ONI casualties in our study were resulted from motorcycle accidents,and wearing a helmet is an effective protection measure.The intravenous methylprednisolone (IVMP) showed no effect on improving the prognosis in patients with conservative treatment.The IVMP shortened the recovery time at the expense of increase in risk of complications.VEP examination is beneficial in prognosis assessment for non-operative ONI patients.The improvement of the amplitude and latency of P wave has close correlations with patients'visual recovery.

Pattern VEP in Adult Amblyopic Patients Requested From Military Service

PURPOSE: To evaluate the pattern VEP in adult amblyopic patients seen in consultation for ophthalmic evaluation as a past of physical examinations for conscription. METHODS: We retrospectively analyzed, 67 men, 20-year-old or older, who had pattern VEP done for the diagnosis of amblyopia from January 2004 to May 2009. P100 latency and P100 amplitude were analyzed. RESULTS: Thirteen patients were non-amblyopic, and 54 patients had amblyopia. Binocular amblyopia and monocular amblyopia were found in 23 and 31 patients, respectively. In the binocular amblyopic patients, four patients were hyperopic, seven patients were myopic, and 12 patients were astigmatic amblyopia. In the monocular amblyopic patients, 15 patients were anisometropic, 12 patients were strabismic, and four patients had organic amblyopia. The value of P100 latency and P100 amplitude were statistically significantly different between non-amblyopic and amblyopic eyes, with check size of 32x32. However, the types of amblyopia among the patients were not different at a statistically significant level. Visual acuity and P100 amplitude were significantly positively correlated. CONCLUSIONS: VEP might be a useful tool for diagnosis of adult amblyopia, especially using a 32x32 check size. This tool may impart the ability to decide relationship between amblyopia and visual acuity by analyzing P100 latency and amplitude values.

Cortical Responses Evoked by the Light and Electricity in the Rabbit Retina

PURPOSE: By recording the electrically evoked potential (EEP) we tried to verify that focal electrical stimulation of retina sends a signal to the cortex that is similar to that elicited by light and also to investigate optimal stimulus parameters. METHODS: Five New Zealand white rabbits were placed under anesthesia. A tungsten bipolar stimulating electrode (diameter: 250 um) was placed on the vitreal surface of the retina. Cutaneous Ag/AgCl patch electrodes of VEP were used to record EEP. EEP was recorded at each stimulation. Focal visual evoked potentials (VEPs) were also recorded and compared to the focal EEP to ascertain cortical origin of the EEP, and similarities of the EEP to the VEP were determined. RESULTS: EEP recordings were elicited in 8 eyes. Current amplitudes which produced detectable responses ranged from 100 to 5000 micro A. In our best series, EEP amplitudes increased by 8 to 119 micro V in response to the current increasing from 100 to 1000 micro A. In comparing latencies of the EEP and focal VEP, the EEP latencies were 12~16 ms faster, which supports our EEP recording was done properly. CONCLUSIONS: EEPs obtained using VEP setting with adequate parameters of current duration and threshold level for the retinal implant showed that use of the EEP response is a good way to monitor the proper functioning of the retinal implant.

Visual Evoked Potentials in Healthy Preterm Infants

PURPOSE: The visual evoked potentials (VEPs) offer a window both on visual system function and on cerebral or neurologic function. The study was performed to evaluate the maturation of VEP in preterm infants and to present a guide to detect high risk neonates who can develop neurodevelopmental abnormalities. METHODS: The VEPs were recorded in response to binocular stimulus with light-emitting diode goggles. VEP recordings were analyzed in 37 healthy neonates who were followed longer than 6 months and neurodevelopmentally normal. RESULTS: 1) The peak latencies of N1 were 158.4+/-42.4 (msec), 159.4+/-40.6, 80.2+/-20.6, 52.4+/-12.0 from 34 to 42 weeks, respectively. 2) The peak latencies of P1 were 227.7+/-34.4 (msec), 187.0+/-35.4, 124.4+/-30.2, 148.3+/- 44.9 from 34 to 42 weeks, respectively. 3) The peak latencies of N2 were 315.4+/-49.9 (msec), 228.6+/-44.2, 205.5+/-69.3, 194.4+/- 89.9 from 34 to 42 weeks, respectively. 4) The peak latencies of P2 were 403.1+/-87.0 (msec), 275.4+/-61.5, 232.5+/-58.7, 255.1+/- 125.1 from 34 to 42 weeks, respectively. 5) The mean amplitude of N1-P1, P1-N2, N2-P2 were 5.3+/-6.8 (microvolt), 5.3+/-5.5, 5.5+/- 4.1 respectively. The peak latencies were inversely related to post-conceptional age (P<0.05). CONCLUSIONS: The peak latencies of each wave were decreased according to the post-conceptional age and these data reflect maturational changes in brain function.