屈光不正对P-VEP影响及法医学意义
发布时间：2018-09-19 14:57
【摘要】： 在临床法医学鉴定中经常涉及到视功能评定的问题，由于被鉴定人常常夸大视功能障碍程度或伪装成视功能障碍，因此，在法医学如何准确客观评定视功能障碍程度是法医学所面临的一个重要课题。视觉诱发电位(visual evoked potential简称VEP)是一种客观评定视功能的方法，在法医学上应用VEP评定视功能具有特殊意义。按刺激光的不同可以将视觉诱发电位分为闪光视觉诱发电位(flash visual evoked potential，F-VEP)和图形视觉诱发电位(pattern visual evoked potential，P-VEP)。P-VEP波群中常用于诊断的是P_(100)(亦称P_1)，其振幅和潜伏期受诸多因素影响。其中屈光状态的影响往往易被忽略，而造成假阳性，从而不能正确判断被检者真实的视功能状态。目前对于屈光不正对VEP的影响的研究主要从其潜伏期、波幅的绝对值变化方面研究，且常限于同一空间频率刺激，对于屈光不正对不同空间频率刺激的VEP的波幅变化率的影响无明确报导。本次试验对40人(80只眼)给予不同的屈光负荷后进行不同空间频率刺激下的VEP检查，通过对其波幅变化率及潜伏期进行比较，进一步探讨屈光不正对VEP的影响及在法医学鉴定中的应用价值。 试验对象与方法 试验对象：来自于中国医科大学在校本科生40人(80眼)，均为男性，年龄为20～25岁，眼科常规检查正常，除近视外无其他眼病，所有眼矫正视力均在1.0以上。 方法：让被检眼注视屏幕中央，遮盖另眼，采用三种不同空间频率(8×8、16×16、32×32)的棋盘格分别刺激，记录最佳矫正视力(1.0，相对屈光负荷为OD)下和分别在此基础上给予+2.00D、+4.00D、+6.00D和+8.00D屈光负荷下的P-VEP波形，相对 屈光负荷为OD组设为对照组，其余屈光负荷组为实验组，与对照 组相比计算出各实验组的P；。波幅的变化率及潜伏期变化值。 统计学分析：采用 SPSS for indows．0统计分析软件，应用 L检验及方差分析方法进行统计分析。 结 果 1．三种不同空间频率堆 X 8、16 X 16J2 X 32）刺激诱发出的 P；。波幅的下降率均随凸透镜屈光度的增加而逐渐增加，H者之间 的相关系数分别为0．999J．992和0．957，P；。振幅的下降率均与 所加凸透镜屈光度之间存在正相关关系。同时结果表明在相同屈 光负荷下，P；。波幅的下降率随刺激空间频率的增加而增加。 2．不同屈光负荷在不同空间频率方格刺激下的P－VEP中 Pl。波幅的下降率离散系数明显小于绝对值的变化值离散系数，经 配对t检验：t＝＝－15．026，P＜0．001。 3．在 40人 80只受试眼中，除 8 x 8格空间频率刺激下＋2 ．00 D屈光负荷组中100潜伏期与对照组相比无显著性差异外K ＞O．05入其余实验组中在同一空间频率格刺激中，随着屈光负荷 的增加，P；。潜伏期延长值也明显增加；在相同屈光负荷下，随着刺 激格空间频率的增高，P；。潜伏期延长值也明显增加。 讨 论 1．屈光不正对P－VEP中P；。波幅的影响 本次实验通过对40人80只眼在不同屈光负荷下的VEP检 测，经统计学分析得出：在同一空间频率刺激下，P；co波幅随着凸透 镜屈光度数的增加而降低，其下降率随凸透镜屈光度数的增加而 增高，即Pl。振幅的下降率与凸透镜屈光度之间存在正相关关系。 这是由于正屈光负荷使图象在视网膜上的成像变得模糊，导致视 敏度下降，且这种视敏度下降程度随屈光负荷的增加而增加。 ·2· 对于同一屈光负荷下，P；。波幅的下降率随刺激空间频率的提 高而增高，这说明在不同空间频率中，屈光负荷对小方格刺激所诱 发出VEP的影响要大于对大方格刺激的影响。 诱发电位反应波的幅值叩波幅）在健康个体内和个体间的 变异较大，因此不能简单说一个人P；。波幅低，就是神经元本身的 病变。本实验通过对不同屈光负荷在不同空间频率刺激下诱发出 Pl。波幅的下降值的离散率及其下降率的离散率进行统计学分析 卜检验入P＜0．001，波幅下降率的离散率明显小于波幅下降值的 离散率，即其个体差异性较小，，可以用于不同个体间的比较。 2．屈光不正对P－VEP中P；。潜伏期的影响 潜伏期主要反映被测试的感觉或运动系统的粗径有髓纤维的 传导功能。潜伏期长，说明传导速度减慢。本实验结果证明，随着 屈光负荷的增加，P；。潜伏期延长值也相继提高，这是由于屈光负 荷的增加使图象在视网膜上成像的图形边缘变得更加模糊，导致 潜伏期的延长。本组实验显示在同一屈光负荷下随着空间频率的 提高，P；。潜伏期延长值也相继增加，说明在屈光负荷对P；。潜伏 期的影响中，高空间频率刺激较低空间频率刺激更为敏感。 3．正确认识屈光不正对P－VEP的影响在客观评价视功能中 的法医学意义 在眼损伤的法医学鉴定中可以充分利用屈光不正对P－VEP
[Abstract]:Visual evoked potential (VEP) is an important subject in forensic science, because the appraised often exaggerate the degree of visual impairment or disguise it as visual impairment. VEP is an objective method for evaluating visual function. It has special significance in forensic medicine to use VEP to evaluate visual function. According to the stimulating light, VEP can be divided into flash visual evoked potential (F-VEP) and pattern visual evoked potential (P-VEP). The amplitude and latency of P_ (100) (also called P_1) are influenced by many factors. The influence of refractive state is often neglected, which leads to false positivity, and thus can not correctly judge the true visual state of the examinee. In this study, 40 subjects (80 eyes) were examined for the amplitude change rate and latency progression of VEP after different refractive loads with different spatial frequencies. To compare the effects of ametropia on VEP and its application in forensic identification.
Test subjects and methods
Subjects: 40 undergraduates (80 eyes) from China Medical University, all male, aged 20-25 years, had normal routine ophthalmic examination, no eye diseases except myopia. All eyes had corrected visual acuity above 1.0.
Methods: Three different spatial frequencies (8 *8, 16 *16, 32 *32) were used to stimulate the examined eye to fix on the center of the screen and cover the other eye. The P-VEP waveforms were recorded under the best corrected visual acuity (1.0, OD) and under the refractive load of + 2.00D, + 4.00D, + 6.00D and + 8.00D respectively.
Refractive load was set as control group in group OD, while in other refractive load group, the experimental group was compared with control group.
The P, amplitude and latency of each experimental group were calculated.
Statistical analysis: SPSS for indows.0 statistical analysis software was applied.
L test and variance analysis were used for statistical analysis.
Result
1. three different spatial frequency reactors X 8,16 X 16J2 X 32) induced by stimulation.
P. The decrease rate of amplitude increases with the increase of the refractive index of the convex lens, and between H.
The correlation coefficients were 0.999J.992 and 0.957, P, respectively.
There is a positive correlation between the refractive index of the convex lens.
Under the light load, the decrease rate of P and amplitude increases with the increase of the spatial frequency of stimulation.
2. the different refraction load under the different space frequency square stimulus of P VEP.
The decrease rate of Pl. amplitude is obviously smaller than that of absolute value.
Paired t test: T = = - 15. 26, P < 0.001.
3. in the eyes of 40 subjects and 80 subjects, except 8 x 8 space frequency stimulus + 2
There was no significant difference in the latency of 100 in.00 D refractive load group compared with the control group, K
> O.05 into the rest of the experimental group in the same spatial frequency stimulus, with refractive load.
The increase of P, latency of the incubation period also increased significantly.
The spatial frequency of excitation increased, P, and latency prolonged significantly.
Discussion
1. the influence of ametropia on P, amplitude of P VEP.
In this experiment, 40 eyes and 80 eyes were examined by VEP under different refractive loads.
Statistical analysis showed that under the same spatial frequency stimulation, the amplitude of P and CO was convex.
The decrease of the refractive index increases with the increase of the refractive index of the convex lens.
There is a positive correlation between the decrease of Pl. amplitude and the refractive index of convex lens.
This is due to the blurring of the image on the retina due to the positive refractive load.
The sensitivity decreased, and the decrease of the visual acuity increased with the increase of refractive load.
2.
For the same refractive load, the decrease rate of P, amplitude decreases with the increase of the spatial frequency of stimulation.
Higher and higher, which indicates that in different spatial frequencies, the refractive load is induced by small square stimuli.
The effect of VEP is greater than that on large square stimuli.
The amplitude of evoked response wave amplitude is between healthy individuals and individuals.
The variation is large, so we can not simply say a person P; the amplitude is low, that is, the neuron itself.
The experiment was induced by stimulation of different diopter loads at different spatial frequencies.
The dispersion rate of the descending value of Pl. amplitude and the dispersion rate of its descending rate were statistically analyzed.
The discretization rate of the amplitude decrease rate is significantly smaller than that of the amplitude decrease in P < 0.001.
Dispersion rate, that is, its individual difference is small, can be used for comparison among different individuals.
2. the influence of ametropia on P. Latency in P VEP.
The incubation period mainly reflects the diameter of the tested sensory or motor system with myelinated fibers.
Conduction function. Long incubation period indicates slow conduction velocity.
The increase in refractive load, P, and latency also increased due to refractive errors.
The increase of load makes the image edge of the image on the retina become more blurred.
Prolongation of latency. This group of experiments showed that with the same refractive load, with the increase of spatial frequency
The increase in P, latency, and latency also showed that the refractive load was P.
High spatial frequency stimulation is more sensitive than low spatial frequency stimulation.
3. correctly understand the effect of ametropia on P VEP and objectively evaluate visual function.
Forensic significance
In the forensic identification of eye injury, we can make full use of ametropia to P VEP.
【学位授予单位】：中国医科大学
【学位级别】：硕士
【学位授予年份】：2003
【分类号】：D919
[Abstract]:Visual evoked potential (VEP) is an important subject in forensic science, because the appraised often exaggerate the degree of visual impairment or disguise it as visual impairment. VEP is an objective method for evaluating visual function. It has special significance in forensic medicine to use VEP to evaluate visual function. According to the stimulating light, VEP can be divided into flash visual evoked potential (F-VEP) and pattern visual evoked potential (P-VEP). The amplitude and latency of P_ (100) (also called P_1) are influenced by many factors. The influence of refractive state is often neglected, which leads to false positivity, and thus can not correctly judge the true visual state of the examinee. In this study, 40 subjects (80 eyes) were examined for the amplitude change rate and latency progression of VEP after different refractive loads with different spatial frequencies. To compare the effects of ametropia on VEP and its application in forensic identification.
Test subjects and methods
Subjects: 40 undergraduates (80 eyes) from China Medical University, all male, aged 20-25 years, had normal routine ophthalmic examination, no eye diseases except myopia. All eyes had corrected visual acuity above 1.0.
Methods: Three different spatial frequencies (8 *8, 16 *16, 32 *32) were used to stimulate the examined eye to fix on the center of the screen and cover the other eye. The P-VEP waveforms were recorded under the best corrected visual acuity (1.0, OD) and under the refractive load of + 2.00D, + 4.00D, + 6.00D and + 8.00D respectively.
Refractive load was set as control group in group OD, while in other refractive load group, the experimental group was compared with control group.
The P, amplitude and latency of each experimental group were calculated.
Statistical analysis: SPSS for indows.0 statistical analysis software was applied.
L test and variance analysis were used for statistical analysis.
Result
1. three different spatial frequency reactors X 8,16 X 16J2 X 32) induced by stimulation.
P. The decrease rate of amplitude increases with the increase of the refractive index of the convex lens, and between H.
The correlation coefficients were 0.999J.992 and 0.957, P, respectively.
There is a positive correlation between the refractive index of the convex lens.
Under the light load, the decrease rate of P and amplitude increases with the increase of the spatial frequency of stimulation.
2. the different refraction load under the different space frequency square stimulus of P VEP.
The decrease rate of Pl. amplitude is obviously smaller than that of absolute value.
Paired t test: T = = - 15. 26, P < 0.001.
3. in the eyes of 40 subjects and 80 subjects, except 8 x 8 space frequency stimulus + 2
There was no significant difference in the latency of 100 in.00 D refractive load group compared with the control group, K
> O.05 into the rest of the experimental group in the same spatial frequency stimulus, with refractive load.
The increase of P, latency of the incubation period also increased significantly.
The spatial frequency of excitation increased, P, and latency prolonged significantly.
Discussion
1. the influence of ametropia on P, amplitude of P VEP.
In this experiment, 40 eyes and 80 eyes were examined by VEP under different refractive loads.
Statistical analysis showed that under the same spatial frequency stimulation, the amplitude of P and CO was convex.
The decrease of the refractive index increases with the increase of the refractive index of the convex lens.
There is a positive correlation between the decrease of Pl. amplitude and the refractive index of convex lens.
This is due to the blurring of the image on the retina due to the positive refractive load.
The sensitivity decreased, and the decrease of the visual acuity increased with the increase of refractive load.
2.
For the same refractive load, the decrease rate of P, amplitude decreases with the increase of the spatial frequency of stimulation.
Higher and higher, which indicates that in different spatial frequencies, the refractive load is induced by small square stimuli.
The effect of VEP is greater than that on large square stimuli.
The amplitude of evoked response wave amplitude is between healthy individuals and individuals.
The variation is large, so we can not simply say a person P; the amplitude is low, that is, the neuron itself.
The experiment was induced by stimulation of different diopter loads at different spatial frequencies.
The dispersion rate of the descending value of Pl. amplitude and the dispersion rate of its descending rate were statistically analyzed.
The discretization rate of the amplitude decrease rate is significantly smaller than that of the amplitude decrease in P < 0.001.
Dispersion rate, that is, its individual difference is small, can be used for comparison among different individuals.
2. the influence of ametropia on P. Latency in P VEP.
The incubation period mainly reflects the diameter of the tested sensory or motor system with myelinated fibers.
Conduction function. Long incubation period indicates slow conduction velocity.
The increase in refractive load, P, and latency also increased due to refractive errors.
The increase of load makes the image edge of the image on the retina become more blurred.
Prolongation of latency. This group of experiments showed that with the same refractive load, with the increase of spatial frequency
The increase in P, latency, and latency also showed that the refractive load was P.
High spatial frequency stimulation is more sensitive than low spatial frequency stimulation.
3. correctly understand the effect of ametropia on P VEP and objectively evaluate visual function.
Forensic significance
In the forensic identification of eye injury, we can make full use of ametropia to P VEP.
【学位授予单位】：中国医科大学
【学位级别】：硕士
【学位授予年份】：2003
【分类号】：D919
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