Abstract
Purpose :
To develop and validate a quick test to assess the contrast sensitivity function (CSF) of the eye that overcomes the disadvantages of long lasting test procedures.
Methods :
Using a LCD-display with a gray-level resolution of 16 bit, a “swipe” contrast sensitivity test was developed and programmed in Matlab. The displayed image incorporates spatial frequencies between 0 and 60 cycles per degree (cpd) that increase from the left to the right and a decreasing contrast from the bottom to the upper part of the screen. Validly and repeatability was tested in 11 healthy subjects (mean age: 28 ± 3 years, mean spherical equivalent refractive error: -0.97 ± 1.67 D), while refractive errors were corrected for the test distance of 4.5 m. The task of the subjects was to indicate the contrast threshold for the displayed spatial frequencies, at the external monitor and swiping the curve using an external mouse. Repeatability was assessed while doing the test 10 times and mean CS was tested against the CS, when using a standard procedure (the TueCSTest) to investigate validity. Coefficient of repeatability (COR) was calculated as the 95 % confidence interval of differences.
Results :
Mean contrast sensitivity assessed with the SwipeCSF test did not differ significantly from the standard procedure, for all tested spatial frequencies (p > 0.05, Friedman). Bland-Altman analysis showed that the SwipeCSF test resulted in slightly higher values for medium (3 cpd < SF <24 cpd) and high (SF ≥ 24 cpd) spatial frequencies (ΔlogCS = 0.12 ± 0.11) and lower values, in case low (SF ≤ 3 cpd) spatial frequencies were measured (ΔlogCS = -0.24 ± 0.17). In general, COR of the SwipeCSF (COR = ± 0.28 logCS) was slightly smaller in comparison to the standard test (COR = ± 0.31 logCS). The assessment of the CSF over a wide range of SF took significantly less time using the SwipeCSF test (t = 1.35 ± 0.57 min) compared to the TueCST (t = 12.3 ± 2.45 min, p < 0.001, t-test)).
Conclusions :
The SwipeCSF Test is an easy to use and easy to understand test of the contrast sensitivity function, with a good validity as well as repeatability, when compared to a standard test. The combination of a high gray scale resolution and time saving procedure enable a huge range of applications for the developed SwipeCSF test.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.