Objective To observe the functional state of the optic nerve and discover the injury of visual pathway function in time under general ane sthesia. The flash visual evoked potential (F-VEP) was used to monitor visual function during orbital surgery. Methods A total of 252 out of 282 patients undergoing orbital surgery under general anesthesia were successfully monitored by F-VEP during the surgery. All patients were monitored by this method under the following conditions:consious state before operation, under general anaesthesia, during and after dissection of orbital tumor and at the end of operation. Results ①There was no significant difference of wave amplitude and latency under general anesthesia and consciousness condition. ②The amplitude and latency of F-VEP were normal in the orbital surgery withou toptic nerve injury. ③Pulling and oppression of optic nerve could cause temporary wave loss, but the wave recovered after removal of the pull and oppression. ④ The wave loss of F-VEP would occur immedicately when optic nerve was severe injured and its blood supply was deficient. Since the application of the visual function monitoring, 24 cases were treated in time during disturbance of visual function and no patient has unexpected visual loss during orbital surgery. Conclusion The intraoperative monitoring of F-VEP during orbital surgery can decrease the proportion of permanent visual loss caused by orbit al surgery, and help the surgical procedures go to function-anatomy stage from experience-anatomy stage. (Chin J Ocul Fundus Dis, 2001,17:260-263)
A new form of static random-dot stereograms free of monocular clues was designed as stimulus to elicit disparity evoked potentials in 40 normal subjects.A characteristic wide positive wave at about 250ms was consistently recorded in disparity stimulation,which may be regard as evdence of the presence of stereopsis.In constrast,recordings for monocular stimulus all demonstrated a relatively smaller and sharper positive wave with a markedly shortened latency. （Chin J Ocul Fundus Dis,1993,9:214-217）
Objective To investigate the characteristic of the multifocal visual evoked potentials(MVEP)and the visual function across the visual field in anisometropic amblyopes and isometropic amblyopes. Methods MVEP from 32 anisometropic amblyopic eyes and 31 control eyes were tested. Results In anisometropic amblyopic eyes,the latencies of MVEP were significantly prolonged．The amplitudes of MVEP were significantly attenuated in the central region of the visual field,and these phenomena gradually reduced with the increase of the eccentricity． Conclusion The visual function of anisometropic amblyopic eyes is reduced more significantly in the central region than in the peripheral region of the visual field. (Chin J Ocul Fundus Dis,20000,16:27-29)
Objective To investigate the distribution properties of multifocal pattern visual evoked potential across visual field. Methods Multifocal pattern visual evoked potentials(VEP) of 14 normals were measured with VERIS ScienceTM4.0The visual stimuli were dart board 60 with patterns which consisted of 60 patches arranged in dart board configuration spanning a 26deg; vis ual field. The temporal modulation of each patch was controlled by a special type of pseudorandom sequence called binary m-sequence. The electrodes were placed at equal distances 2 cm inferior to and 2 cm superior to and straddling the inion. The first slice of the second order kernel for each stimulus patch was analysed. The 60 patches were grouped into several sectors. The summed responses of these sectors were analysed and compared. Results Compared with that of the lower hemifield , the polarity of the multifocal VEP of the upper hemifield was reverse, and the latency delayed, the response density decreased. With the eccentricity increased, the response density of the multifocal VEP decreased. The properties of the multifocal VEP of the horizontal sectors were different from that of the vertical sectors. Conclusion VEP of many locations within visual field could be recorded simultaneously in a short time with the method of mutifocal VEP. The multifocal VEP showed different properties in different sectors within visual field. (Chin J Ocul Fundus Dis, 2001,17:280-283)
Objective To observe the content of thromboxane (TXA2 ) and prostacyclin (PGI2) in optic nerves after forehead impact injury.Methods The right forehead zones of 32 rabbits were struck by biology impact machine. Tweenty-four rabbits that had afferent papillary defect after injury were chosen, and randomly divided into four groups: 1 day, 2, 4, and 7 days group. Right eyes were in the experimental group and left eyes were in the control group. Flash visual evoked potentials were examined before and after the traumatic injury. The rabbits ′eyes were removed, the optic nerves were pathologically examined, and the content of TXB2 and 6-Keto-PGF1αwhich were the products of TXA2 and PGI2 were assayed 1, 2, 4, and 7 days after traumatic injury respectively.Results Histopath ological examination revealed the findings of injuries of optic nerves of all the 24 rabbits. The latency of wave P1 was significantly delayed after traum atic injury (Plt;0.01), and amplitude of wave P1 was significantly decreased after traumatic injury (Plt;0.01). The content of TXB2 ［(172.35±26.52) pg/mg ］and 6-Keto-PGF1α［(161.78±24.83) pg/mg］were significantly higher in the injured optic nerves than in the uninjured ones 1 day after the traumatic injury (Plt;0.01). The rate of TXB2 /6-Keto-PGF1α (1.077±0.18) was significantly increased compared to the control group (Plt;0.05), and lasted to the 7th day.Conclusions The content of TXA2 and PGI2 significantly increases and the ratio of them is lopsided after forehead impact injury in rabbits. (Chin J Ocul Fundus Dis，2003，19：49-51)
Purpose To investigate the influence of ametropia on stereopsis and its mechanism by using the disparity evoked potential testing. Methods A new set of static random dot stereograms was utilized as a stimulation to elicit the disparity evoked potentials in 21 ametropes and 40 stereo normal subjects. Rezults The P250 wave,which was related to stereoscopic stimulation in ametropes,was recorded in both the ametropes and emetropic stereo normal persons in this series,and the characteristic changes of P250 wave with increasing visual disparity in ametropes were similar to those in normal subjects.The differences of mean amplitudes and latencies of P250 waves between myopes and hyperopes were not significant. Conclusion Ametropia in full correction dose not significanly affect the function of stereopsis. (Chin J Ocul Fundus Dis,1998,14:225-227)
Objective To observe the changes of amplitude and latency of mini visual evoked optential (mini VEP) examinations in infants at different age.Methods A total of 84 healthy infants and adults (168 eyes) were randomly selected to underwent mini VEP. According to the age, all the individuals were divided into seven groups: A, 0-3 months; B, 4-6 months; C: 7-12 months; D: 1-3 years; E: 4-6 years; F: 7-12 years; G: adults (control). There were 12 individuals (24 eyes) in each group. By using the stimulater of mini VEP, the flash VEP was performed and the changes of amplitude and latency of P100 wave were recorded and analyzed.Results The average value of amplitude in group A was（7.39plusmn;1.79）mu;V which was the lowest, and the average latency was （137.45plusmn;7.64）ms which was the largest.At the same time, the average amplitude of P100 increased from group A to E (F=359.56); the average latency decreased from Group A to D（F=326.64）; the difference was significant (P＜0.01). The amplitude in group E, F, and G was high and no significant difference was found (F=2.39，P＞0.05);the latency in group D,E,F,and G was short with no significant difference (F=2.64，P＞0.05）.Conclusions With the growth of the infants' age, the amplitude of miniVEP increases and latency decreases; moreover, the latency reaches the normal adult level in advance of the amplitude of miniVEP.
Objective To compare the effect of electrode positions on multifocal visual evoked potential(mf-VEP). Methods Ten healthy individuals were tested with RETIscan multifocal VEP system 3.20, each individual was tested with four electrode positions: the active and reference electrode were placed 2.0 cm above and below the inion in Ch1；3.0 cm above and 4.5 cm below the inion in Ch2；2.0 cm on both right and left side of the inion in Ch3 and 4.0 cm on both right and left side of the inion in Ch4. The summed amplitudes of hemifield mf-VEP were analyzed and compared according to different electrode positions. Results The difference among summed amplitudes of the upper or lower hemifield mf-VEP recorded with Ch1、Ch2、Ch3 and Ch4 was statistically significant；and the difference between Ch2 and the other channels was statistically significant too. The difference among summed amplitudes of the horizontal sites whose amplitudes were small when recorded with Ch2 and summed amplitudes of the corresponding sites recorded with Ch3 and Ch4 were statistically significant；and the difference between Ch4 and the other channels was statistically significant too. Conclusions compared to Ch1、Ch3 and Ch4, Ch2 can make a better recording of mf-VEP. As for some sites, especially those along horizontal line, horizontal electrodes could improve the amplitudes of mf-VEP recorded with vertical electrodes，and Ch4 could do better to improve the mf-VEP recorded with Ch2 than Ch3. (Chin J Ocul Fundus Dis，2004，20：346-348)
ObjectiveTo observe the changes of vision and visual evoked potentials (VEP) in patients with Leber hereditary optic neuropathy (LHON) before and after gene therapy.MethodsA retrospective cohort study. From December 2017 to October 2018, 35 cases of 70 eyes of m11778G.A/MT-ND4 mutant LHON patients who were diagnosed in the Tongji Hospital of Huazhong University of Science and Technology and received gene therapy were included in the study. There were 30 males (87.71%) and 5 females (12.29%), with the mean age of 23.31±6.72 years. The gene therapy method was intravitreal injection of rAAV2-ND4 (recombinant adeno-associated virus carrying NADH-ubiquinone oxidoreductase subunit 4 gene) into one eye. The eye with poor visual acuity was chosen as the injection eye. If both eyes had the same visual acuity, the right eye was designated as the injection eye. Seventy eyes were divided into the injected eye group and the non-injected eye group, in which were both 35 eyes. The best corrected visual acuity (BCVA) and pattern VEP (PVEP) examinations were performed in the injected eye group and the non-injected eye group before treatment (baseline), 1, 3, and 6 months after injection. Compare the changes of BCVA and PVEP between the injected eye group and the non-injected eye group at baseline, 1 month, 3 months, and 6 months after injection. Independent sample t test, paired sample t test or two independent sample nonparametric test were performed to compare the two groups.ResultsCompared with baseline, 1, 3, and 6 months after treatment, the BCVA of the injected eye group (t=3.530, 4.962, 5.281; P=0.001, 0.000, 0.000) and the non-injected eye group (t=3.288, 2.620, 2.252; P= 0.002, 0.013, 0.031) increased, and the difference was statistically significant; there was no statistically significant difference between VEP IT (tinjected eye group=?0.158, 1.046, ?1.134; Pinjected eye group = 0.875, 0.303, 0.190; tnon-injected eye group=0.773, ?0.607, ?0.944; Pnon-injected eye group= 0.445, 0.548, 0.352) and VEP A (Zinjected eye group=?0.504, ?0.934, ?1.065; Pinjected eye group= 0.614, 0.351, 0.287; Znon-injected eye group=?0.521, ?0.115, ?0.491; Pnon-injected eye group = 0.602, 0.909, 0.623).ConclusionAfter gene therapy, the visual acuity of the injected and non-injected eyes of LHON patients improved; PVEP did not change significantly, and remained stable compared with baseline.
objective To observe the differences between four- and single-channel recording of normal multifocal visual evoked potential (mfVEP). Methods mfVEP of 35 health individuals (70 eyes) were detected by both four- and single-channel recording with VERIS apparatus. The root mean square (RMS) value of reactive amplitude was obtained from the results of the two kinds of recording. Each stimulated patch was analyzed to compare the variational degree of each patch between the two recording methods. Responase sasymmetry coefficient (RAC) was introduced to evaluate the symmetry property between the two eyes in an individual. Results Compared with the single-channel recording,the responses of the stimulated patches of the four- channel recording were increased statistically, with most of the patches below the horizontal meridian and some of patches in the upper field, and there was distinct symmetry property between the two eyes in the same individual recorded by four-channel recording. Conclusion The four-channel recording is better than the single one and could be clinically applied and popularized.(Chin J Ocul Fundus Dis，2004，20：156-159)