The new numbers contrast sensitivity chart for contrast sensitivity measurement

Abstract

Purpose: To develop and assess the agreement between the 3 newly made numbers contrast sensitivity charts and the MARS contrast sensitivity chart (MARS) in contrast sensitivity measurement. Methods: We developed 3 numbers contrast sensitivity charts for right, left and both eyes. Two hundred subjects were assigned to read numbers 0-9 for determining the degree of difficulty. Selected seven numbers were randomly arranged and the contrast of each number was decreased by the constant factor of 0.04 log units in the units as in the MARS. We assigned 112 subjects with visual acuity range from 20/480 to 20/20 to test once with the new chart and then with MARS Chart monocularly and binocularly by random order. Bland-Altman analysis for comparing two charts was performed. Results: Bland-Altman analysis between 2 charts showed the mean differences were 0.04, 0.03, 0.04 log CS and the 95% limit of agreement (LOA) of the bias were (+0.26, −0.19), (+0.26, −0.20), (+0.25, −0.17) log CS for right, left and binocular. The Bland-Altman plot indicates a good concordance in 3 charts. Conclusions: These charts show reasonable agreement and can be used interchangeably with the MARS. It is helpful for Thai people who can only read numbers in doing the test. We can use them in routinely contrast sensitivity measurement.

Keywords

• Visual acuity
• Contrast
• Vision
• Chart
• Test