The tests are designed to create a play situation where the child never experiences failure. When no longer correctly recognized, the symbols transform into circles appropriately called "rings" or "balls" by the child. The child can still perceive that he/she is answering "correctly", while the examiner can easily detect the acuity threshold.

The system features line tests, single symbol tests and a crowded symbol test at high contrast. Low contrast line test with five contrast levels also available. Instructions are included with each test.