Assessment of contrast sensitivity (CS) is an important component of a comprehensive eye examination. The test should be administered by a vision health professional or a person trained in administering vision tests. The test results should be interpreted in the context of the individual’s overall presentation and the results of the individual’s eye examination. If the individual’s test shows abnormal results, we recommend retesting, preferably by a different tester who is unaware of the first tester’s results. A CS test does not replace the eye examination. The Mayer-Kran™ Double-Happy™ Low Contrast Test consists of cards printed with a schematic smiling face. The face elements on each card are darker than the white card. The darkness of the face relative to the background is calibrated in percent contrast (Weber formula). Contrasts range from nearly black (89%) to very dim (2.2%). (Screening set -2.2%, Full set -0.8%). (The face contrast values are converted into log contrast sensitivity or logCS.) The M-K Double-Happy Contrast Screening Test is offered with two options: The Screening Set is a set of 6 cards varying in Weber contrast: 89, 36, 25, 12.6, 6.3, 3.2, 2.2 logCS Values are: 0.05, 0.45, 0.60, 0.90, 1.20, 1.50, 1.65 The Full Set is a set of 16 cards varying in Weber contrast: 89, 71, 50, 36, 25, 17.8, 12.6, 8.9, 6.3, 4.5, 3.2, 2.2, 1.6, 1.1, 0.8, Blank logCS Values are: 0.05, 0.15, 0.30, 0.45, 0.60, 0.75, 0.90, 1.05, 1.20, 1.35, 1.50, 1.65, 1.80, 1.95, 2.1 The logCS values can be related to difficulties in visually guided activities in adults. For example, logCS values ≤ 0.9 may be associated with a serious disability in walking, ≤ 1.3 may result in significant difficulties in recognizing faces, and
