The Cardiff Acuity Test is designed especially for the hard to test age group, 12 months to 30 months. It uses familiar pictures and a procedure in the form of a game to attract and keep the attention of young children. It relies on the technique of "preferential looking" - that is, the observer simply notes the child's eye movements in order to determine whether he or she can see the picture.
The test is available in two versions. The standard version covers a range of visual acuity levels from 6/48 and 6/96 to 6/3.75 and 6/7.5 (at working distances of 1 metre and 50 cm). The Low Vision version, aimed at practitioners working in the field of visual impairment, covers 6/96 and 6/192 to 6/7.5 and 6/15, at the same working distances. This test is also available in an adult version, an contrast test, and a near test (price on application).