The Three Meter Crowded Book combines the accuracy of LogMar acuity testing with the ease of naming pictures.It is suitable for use with children aged from about 36 months. Any child who does not yet know his letters can read out the row of pictures rather than struggle to match from a row of unfamiliar letters . This means the test will be easier for the child and quicker to perform.
Eight pictures are used in groups of four throughout the test(except sizes 1.0 and 0.9 , where there are two per line). Each eye is tested with a different arrangement of pictures to avoid memory playing a part . At each acuity level the same four pictures are arranged in a different order to test the other eye , giving a perfect comparison of the two acuities .
The test book comprises sizes LogMar 1.0 to -0.1 in twelve equal steps. The book index shows Snellen sizes in feet and metres as well as LogMar, so there is no need to convert.