Now it's easy to measure, record and detect changes in the transfer of visual information when the change only affects visual acuity at low contrast levels. Chart presents numbers at the following contrast levels: black, 25%, 10%, 5%, 2.5%, and 1.25%. Pages are offset for easy flipping. Each chart includes recording forms and instructions. 6 pages, 3.25" x 9" (8.25 cm x 22.9 cm).