单眼视力下降对双眼对比敏感度的影响

The Effect of Monocular Vision Decline on Binocular Contrast Sensitivity

目的:研究单眼视力下降时双眼对比敏感度(CS)的变化规律,初步探讨单眼视力下降对双眼视功能及双眼相互作用的影响,并且探讨其在司法鉴定中的运用价值。方法:实验研究。于2016年3月至2017年8月选择司法鉴定科学研究院志愿者46例(男24例,女22例)。单眼矫正视力或裸眼视力均达4.9以上,主导眼前放置试验透镜,用插片法诱导实验性单眼视力不同程度下降。分别测试其左眼、右眼及双眼的视力、CS,计算对比敏感度双眼总和比(BSR)。数据进行球形检验、方差分析及秩和检验。结果:单眼视力下降可引起双眼视力一定程度下降,但是双眼视力仍优于单眼。当视力下降至轻度损害水平时,全频段正常倒“U”形CS曲线形态已破坏,且相较低空间频率而言,中、高空间频率时CS下降程度更为明显;在高频区且两眼视力均正常时,出现最大的BSR,为1.48。当单眼视力逐渐下降时,出现双眼平均及抑制(BSR<1)。提示双眼相互作用的形式存在一定程度的容忍性及空间依赖性。结论:单眼视力下降对双眼CS、双眼相互作用的形式及程度具有一定程度的影响。运用双眼CS检测,能够反映单眼视力的损害程度,具有临床及司法鉴定运用价值。

Objective: To study the changes in binocular contrast sensitivity (CS) when monocular vision declines, and to explore the effects of monocular vision decline on binocular function and interaction, and to explore the value of judicial appraisal. Methods: In this experimental study, 46 normal subjects (24 males and 22 females) were enrolled in Academy of Forensic Science from March 2016 to August 2017. Monocular visual acuity of them could be corrected to more than 4.9. Experimental lenses were placed in front of the dominant eyes to induce experimental monocular visual impairment in varying degrees. Visual acuity and CS for monocular and binocular function were measured. Binocular summation ratios (BSR) were calculated, further spherical tests, analysis of variance and the Kruskal-Wallis test. Results: Decreased monocular vision can cause a certain decrease in binocular vision, but binocular vision is still better than monocular vision.When visual acuity declined to the level of mild damage, the normal inverted U-shaped curve of the whole frequency band was destroyed, and visual acuity had a more obvious decline at medium and high spatial frequencies than at low spatial frequencies. At high frequencies and normal visual acuity in both eyes, the maximum sum of both eyes appeared (BSR=1.48). When monocular visual acuity gradually declined, the binocular average and inhibition appeared (BSR<1). There was a certain degree of tolerance and spatial dependence with binocular interaction. Conclusions: Decreased monocular vision has a certain influence on binocular CS and the form and degree of binocular interaction. A binocular CS test can reflect the degree of monocular vision loss. It has practical value and is worthy of clinical application and judicial expertise.