1 Shanghai Key Laboratory of Forensic Medicine, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai 200063, China; 2 Jiamusi University, College of Basic Medicine, Jiamusi 154000, China; 3 Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun-Yat Sen University, Guangzhou 510080, China
Abstract: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.
Paulsson LE, Sjöstrand J.Contrast sensitivity in the presence of a glare light. Theoretical concepts and preliminary clinical studies. Invest Ophthalmol Vis Sci, 1980, 19(4): 401-406.
[2]
李风鸣. 眼科全书. 北京:人民卫生出版社, 1996: 390-391.
[3]
Schwarz C, Manzanera S, Prieto PM, et al.Comparison of binocular through-focus visual acuity with monovision and a small aperture inlay. Biomed Opt Express, 2014, 5(10): 3355-3366. DOI: 10.1364/BOE.5.003355.
[4]
Vedamurthy I, Suttle CM, Alexander J, et al.A psychophysical study of human binocular interactions in normal and amblyopic visual systems. Vision Res, 2008, 48(14): 1522-1531. DOI: 10.1016/j.visres.2008.04.004.
[5]
Cruz AA, Bauer J, Held R.Inhibition of binocular contrast sensitivity in hypermetropic anisometropia. Optom Vis Sci, 1991, 68(10): 819-820.
[6]
Jiménez JR, Ponce A, Anera RG.Induced aniseikonia diminishes binocular contrast sensitivity and binocular summation. Optom Vis Sci, 2004, 81(7): 559-562.
[7]
Pardhan S, Gilchrist J.The effect of monocular defocus on binocular contrast sensitivity. Ophthalmic Physiol Opt, 1990, 10(1): 33-36.
[8]
Azen SP, Varma R, Preston-Martin S, et al.Binocular visual acuity summation and inhibition in an ocular epidemiological study: The Los Angeles Latino Eye Study. Invest Ophthalmol Vis Sci, 2002, 43(6): 1742-1748.
Ferree CE, Rand G, Buckley D.A study of ocular functions, with special reference to the lookout and signal service of the navy. J Experiment Psychol, 1920, 3(5): 347-356. DOI:10.1037/h0074290.
[15]
Meese TS, Georgeson MA, Baker DH.Binocular contrast vision at and above threshold. J Vis, 2006, 6(11): 1224-1243. DOI: 10.1167/6.11.7.
[16]
Goodwin RT, Romano PE.Stereoacuity degradation by experimental and real monocular and binocular amblyopia. Invest Ophthalmol Vis Sci, 1985, 26(7): 917-923.
[17]
Singh D, Aggarwal S, Sachdeva MM, et al.Effect of induced monocular blur on monocular and binocular visual functions. Indian J Clin Experiment Ophthalmol, 2015, 1(4): 197. DOI: 10.5958/2395-1451.2015.00015.3.