The Frankfurt-Freiburg Contrast and Acuity Test System (FF-CATS): A New Test to Determine Contrast Sensitivity at Different Luminance Levels with and without Glare
Terzi E.1, Bühren J.1, Bach M.2, Wesemann W.3, Kohnen T.1
1Dept. of Ophthalmology, University of Frankfurt/Main; 2Dept. of Ophthalmology, University of Freiburg; 3College of Optometry (HFAK), Cologne
Purpose: To evaluate a newly designed computer-based test system for the measurement of contrast thresholds at different luminance levels with and without glare.
Method: The FF-CATS is a psychophysical test based on the Freiburg Visual Acuity Test (FVAT) using an 8-alternative forced choice and the best PEST (parameter estimation by sequential testing) algorithm to measure automatically and observer-independently acuity and contrast thresholds. Landolt rings of 100 in diameter (Snellen equivalent 20/400) are displayed at different contrasts on a high resolution monitor at 167 cd/m-2. For testing at the scotopic luminance level (0.167 cd/m-2), a neutral filter with t=10-3 was used to reduce monitor luminance. 40 eyes of 40 volunteers (group I: 20 eyes, age 21-47 years; group II: 54-69 years) were examined with the FF-CATS and with the Functional Acuity Contrast Test (F.A.C.T.) at 0.167 cd/m-2 and 167 cd/m-2 and with the Pelli-Robson chart (PRC) at 100 cd/m-2. Tests were performed with and without glare in a randomized order. The whole test sequence was re
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