Agreement of measurement of contrast sensitivity and its function using Freiburg Visual Acuity and Contrast Test and quick Contrast Sensitivity Function

Contrast sensitivity plays a vital role in the assessment of visual function and the need for psychometric measurement has found its importance in optometry. Earlier, visual acuity charts like Pelli-Robson and Mars charts were used which only detects the generalized defects and was used predominantly in out-patient procedure because it was easy, and less time is required. But one of the disadvantages was the lack of ability to detect frequency-based deficits. There are many works of literature based on the comparison of various contrast sensitivity charts but there is a lack of evidence to check the test-retest variability and agreement between Freiburg Visual Acuity and Contrast Test [FrACT] and quick Contrast Sensitivity Function [qCSF]which also measures the contrast threshold using psychophysical technique.The aim of the study is to check the agreement and stability of measurements taken at different time points using Freiburg Visual Acuity and Contrast Test and quick contrast sensitivity function. And to determine the limits of agreement and check the test-retest variability of Freiburg Visual acuity and Contrast Test and quick Contrast Sensitivity Function.