Contrast Sensitivity Testing in Visually Normal Individuals: Letter vs. Continuous Text

Contrast sensitivity is a visual element used in optometric examinations to help assess visual capacity. This study compared two formats of contrast sensitivity tests, ETDRS Letters and Continuous Text. Methods: Contrast sensitivity was measured in 75 subjects, who met inclusion criteria, using the Adult Near Contrast Test. Patients’ verbal readings provided data for the formats at five contrast levels. Results: Average visual acuity and number of lines/paragraphs read correctly decreased with decreasing contrast. ANOVAs showed significant differences by contrast level in total words and total letters (ps< 0.001) and a Pearson correlation gave high correlations between the contrast sensitivity readings of the two formats except at 100% contrast (ps< 0.05; p= 0.69). Conclusion: Analysis revealed that contrast sensitivity readings from the different formats were essentially the same for most contrast levels. These two test formats can both be used with success in measuring contrast sensitivity in a normally sighted population.