Contrast sensitivity in preschool children
A new Low Contrast Test was tested in examination of 40 young children (34-59 months of age) in day care center environment. The test is based on the four LH-symbols (apple, house, ball, window) that blur equally. The lay out of the different contrast levels (25, 10, 5, 2.5, 1.2 and 0.6%) on one page makes the test situation so easy that three-year-old children can complete the test binocularly during the first testing. Children older than 44 months could be tested also monocularly with two exceptions out of 26 children.
Children reach an adult like function at low contrast levels earlier than thought before. At the optotype size 0.1. (20/200) all children reached 1.2% contrast level corresponding contrast sensitivity 80. In case the younger children could get accustomed to the test situation, repeated testing might reveal still better function, especially in the youngest testable groups.
(This investigation was completed in 1991 and reported at a meeting but was not published in a journal. The LH-Symbols preceded the present LEA Symbols but the difference is hair splitting.)