对比度视力容许区间在鉴别伪装视力降低中的应用

目的探索法医学鉴定中运用对比度视力方法鉴别被鉴定人伪装或夸大视力降低的价值。方法根据前期对比度视力与投影仪视力相关性的研究结果,收集正常志愿者166眼作为对照组,分别检测投影仪视力与100%、25%、10%视标对比度下的对比度视力,获得不同投影仪视力水平与以上视标对比度下相应的视力95%容许区间;收集眼外伤被鉴定人64眼,根据其100%对比度视力值是否在相应对比度视力的容许区间内,分为A组（初步排除伪装或夸大视力降低）与B组（疑有伪装或夸大视力降低组）。运用统计学软件进行数据分析。结果投影仪视力检测值≤0.3以及0.4~0.7组的受检眼,在不同对比度视标检测下,A、B组的差异均有统计学意义（P≤0.05）;投影仪视力检测值≥0.8组的受检眼,在不同对比度下,A、B组的差异无统计学意义（P≥0.05）。结论当被鉴定人受伤眼的投影仪视力在0.8以下,可加测对比度视力。参照投影仪视力对应的对比度视力容许区间,当受检眼对比度视力值在容许区间以外,应考虑其存在伪装或夸大视力降低。

Application of the Tolerance Intervals of Contrast Vision in Identifying the Malingering Decreased Vision in Forensic Medicine

Objective To evaluate the application of contrast vision in identifying the malingering decreased vision or blindness in forensic medicine. Methods 100%, 25% and 10% contrast visual acuity and projected vision were evaluated in 99 volunteers based on the previous researches, and tolerance intervals of contrast vision at different optotype contrast levels were obtained （n=166 eyes）. 100%, 25% and 10% contrast visual acuity and projected vision were also evaluated in 60 suspects （n=64 eyes）, of which the data had been randomized to group A and B, according to the tolerance intervals of contrast vision on contrast of 100%. Malingering was excluded in group A, while group B was considered malingering. All data were analyzed statistically. Results At different contrast levels, when the project vision ranged from 0.4 to 0.7, or was lower than 0.3, the difference be- tween group A and group B was significant （P≤O.05）. On the other hand, no significant difference was observed between the two groups when the project vision was higher than 0.8 （P≥0.05）. Conclusion When the project vision of the suspect is lower than 0.8, the contrast vision should be further evaluated. Referring to the tolerance intervals, when the project vision of the sus- pect is beyond the interval, the possibility of malingering should be taken into consideration.