Effects of Binocular Acuity in Visual Impairment Assessment

Guangfeng Wu

doi:10.18483/ijsci.853

Abstract

Objective: To study the correlations and differences between best corrected visual acuity in the better eye (hereinafter referred to as monocular acuity in the better eye) and binocular acuity after both eyes were best corrected separately (hereinafter referred to as binocular acuity), the relationship between both monocular acuity in the better eye and binocular acuity and reading acuity as well as reading speed were discussed in order to investigate the effect of binocular acuity in visual impairment and visual disability assessment. Methods: Two thousand a hundred and fifteen subjects ranging in age from 18 to 40 years old were recruited for the study, whose best corrected monocular acuity were less than or equal to 0.8, and other visual functions examined were normal. Best corrected visual acuity was measured monocularly and binocularly using Standard Logarithm Distance Charts. Reading visual acuity and reading speed were also determined. Experimental data were statistically analyzed using SPSS19.0 statistical software. Results: Monocular acuity in the better eye and binocular acuity was linear correlation (r=0.920, P<0.001), and the differences of them were statistically significant (Z=-23.025, P<0.05); Reading acuity and both monocular acuity in the better eye and binocular acuity were also linear correlation (r=0.827, P<0.001; r=0.862, P <0.001); Reading acuity deteriorated with aggravation of visual impairment.There were no differences of reading speed in visual impairment individuals that more than or equal to 0.3; However ,reading speed in visual disability (visual acuity was less than 0.3) individuals were slowed down significantly. Conclusions: Both of monocular acuity in the better eye and binocular acuity could estimate visual function preferably. There were also differences between both of them. In view of people are simultaneously using both eyes in daily life, it is suggested that the visual function of binocular acuity was recommended in the evaluation of judicial forensic visual impairment and visual disability.

Highlights

There were 1004 cases whose binocular acuity was improved compared with monocular acuity in the better eye which was accounting for 64.61% of 1554 participants with monocular acuity equaled to 0.1 or better, thereinto, 946 improved one line according to the Standard Logarithmic Visual Acuity Chart, two and three line were 50 and 8, separately; 539 were unchanged which was accounting for 34.68%; Decliners of binocular acuity were accounting for 0.71% with 11 cases
2.2 Correlation analysis compares reading acuity to monocular acuity in the better eye and binocular acuity There was a linear correlation between monocular acuity in the better eye, binocular acuity and reading acuity showed by Spear-man correlation analysis,which correlation coefficients were r=0.827, P
2.3 Varying degrees of visual impairment effect on reading visual acuity The visual acuity was divided into three groups, and participants who were unable to read in each group was counted (Table 1)

Summary

Introduction

The relationship between monocular acuity in the better eye and visual function in visual impairment individuals, as well as binocular acuity was studied in this paper. The minimum print size of the text that corresponds to a visual acuity was the final reading http://www.ijSciences.com acuity,recorded it.

Results

Conclusion