Quantitative Analysis of Contrast Sensitivity to Improve Visual Acuity and Reduce Optical Aberrations



Nabavi S¹ ; Mehridehnavi A² ; Vard A² ; Mohammadpour S³ Show Affiliations
Source: Journal of Isfahan Medical School Published:2016

Abstract

Background: Human visual perception in detection of an object from background is based on edge emission and contrast. The optical aberration is the main factor to degrade quality of image in the eye. People with this complication perceive images with low levels of contrast and distorted edges. Since the conventional methods are cumbersome, the new complementary method such as Pre-compensation is offered for display devices. In this research we investigate quantitative effect of the contrast between the object and the background to reduce the effect of low order optical aberration by increasing regional contrast. We tried to find out which contrast level could improve visual acuity in Weber-contrast. Methods: In this Research, 12 optical charts with different levels of contrast were designed based on the log MAR standard. Then obtained patterns were tested on 20 patients with low order optical aberrations. The results of each chart were analyzed using SPSS software. Findings: There was a significant difference in visual acuity of persons at different contrast levels. But, when the Weber contrast percent was low, the difference was not remarkable. Conclusion: Based on the obtained results, a background with lower contrast improves visual acuity approximately up to 11% in the log MAR scale. Therefore, to improve visual acuity in display devices, foreground is more appropriate that be in higher state of brightness than background. © 2016, Isfahan University of Medical Sciences(IUMS). All rights reserved.