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 observe the results of multifocal visual evoked potential (mfVEP) examination in patients with anterior ischemic optic neuropathy (AION) before and ater treatment, and to probe its clinical significance. Methods A total of 90 patients (90 eyes) with AION were examined by mfVEP; the secondorder reaction of mfVEP was analyzed.The reaction was divided into upper and lower hemi field of visual field, or 1/4 quadrant visual field (superior nasal, inferior nasal, superior temporal, and inferior temporal). The sum of waves of each response was analyzed and the results in various regions were compared.The features of wave configuration was compared between the AION eyes and the contralateral eye, and between the AION eyes before and after treatment.Results The amplitude and latency of P-wave of mfVEP was 0.198plusmn;0.033 and 100.197plusmn;7.354 respectively in AION eyes before treatment, and was 0.271plusmn;0.024 and 98.567plusmn;6.794 in the contralateral eyes; the difference was significant (t=16.556,18.330; Plt;0.01). The amplitude and latency of P-wave of mfVEP was 0.229plusmn;0.016 and 100.104plusmn;10.603 respectively in AION eyes after treatment, which differed much from that before the treatment (t=13.649, 8.858; Plt;0.01) and also from that of the contralateral eyes (t=13.649，8.858；P＜0.01). ConclusionsThe amplitude and latency of P-wave of mfVEP may accurately reflect the recovery of local optic nerve damage in AION eyes before and after treatment with good repeatability. AION can be used as a new method for AION diagnosis and detection of the prognosis.
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)
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)
ObjectiveTo investigate the value of pattern reversal visual evoked potential (PRVEP) and sweep pattern visual evoked potential (SPVEP) in evaluating the visual function of patients with central serous chorioretinopathy (CSC).MethodsA retrospective clinical trial. A total of 38 monocular CSC patients were enrolled from March 2016 to December2018 in Heping Hospital Affiliated Changzhi Medical College. There were 34 males and 4 females with the mean age of 40.0±5.2 years. All patients undergo PRVEP detection in both the acute phase (disease course ≤ 3 months) and the clinical cure phase (disease course ≤ 6 months) using the German Roland electrophysiological RETIport system.The stimulation pattern adopted a checkerboard with 1.00° and 0.25° stimulation angles. The P100 peak amplitude and peak time were observed. SPVEP inspection equipment and methods were the same as PRVEP, and the spatial frequency was 1, 2, 4, 6, 8, 12, 16, 22 cpd. The difference between SPVEP vision and subjective vision were compared. The PRVEP peak amplitude, peak time and SPVEP amplitude and phase of the affected eye and the contralateral eye were compared by paired t test; the subjective vision and SPVEP visual acuity of the affected eye and the contralateral eye were compared by Wilcoxon paired rank test; Pearson product-moment correlation analysis was performed on SPVEP vision.ResultsIn the acute phase, the peak amplitude of P100 in the affected eye was lower than that in the contralateral eye (t=30.26, 13.59), and the peak time was prolonged (t=－19.89, －29.41). The difference was statistically significant (P＜0.01); in clinically cured period, the P100 peak amplitude (t=1.49, －0.57) and peak time (t=－1.22, －1.84) of the affected eye and the contralateral eye showed no significant difference (P＞0.05). In the acute phase, the difference in SPVEP amplitude between the affected eye and the contralateral eye with different spatial frequencies was statistically significant (P＜0.01); the phase of the affected eye and the contralateral eye were compared about the spatial frequency 1, 2, 4, 6, 8, 12 cpd, the difference was statistically significant (P＜0.01). During the clinical cure period, the spatial frequency of 6, 8, 12, 16 cpd, the SPVEP amplitude of the affected eye and the contralateral eye, the difference was statistically significant (P＜0.01); on the spatial frequency of 6, 8, 12 cpd, the phase of SPVEP was compared between the affected eye and the contralateral eye, the difference was statistically significant (P＜0.01). During the acute phase and the clinical cure phase, the SPVEP visual acuity of the affected eye was lower than that of the contralateral eye, and the difference was statistically significant (P＜0.01); during the acute phase and clinical cure phase, the SPVEP visual acuity of the affected eye and the contralateral eye were lower than the subjective vision. The difference was statistically significant (acute phase: Z =－5.38, －3.00; P＜0.001, 0.003; clinical cure phase: Z=－5.36, －5.38; P＜0.001,＜0.001). In the acute phase, the subjective visual acuity of the affected eye was positively correlated with SPVEP visual acuity (r=0.847, P＜0.001).ConclusionsPRVEP and SPVEP are useful for objectively assessing the visual function of the patients with CSC. Especially, the slight and potential visual impairment in CSC can been detected by SPVEP.
Commonly clinical visual electrophysiological detection methods include flash ERG, pattern ERG, VEP and multifocal ERG, etc. These inspection methods play an important role in disease identification and visual function judgment. However, lacking of understand the basic principles of electrophysiological testing, misunderstandings of the clinician influence the choice of examination methods or interpretation of examination results. The understanding of the basic principles of electrophysiological testing and analysis of the causes of these misunderstandings have important clinical significance in the correct application of visual electrophysiological testing technology.