Two smaller groups 6.3M to 1.6M for repetitive testing (20/32, 6/9.5 to 20/8, 6/2.4 equiv.).
Can be wall-mounted.
Patti Pics use 5 symbols that are easily recognizable and fun for children. The symbols include House, Apple, Circle, Square, and Star. Each optotype has been calibrated to be equally difficult and to blur equally at threshold. This calibration coupled with Patti Pics being based from the Sloan standard, help to minimize any unintended loss or gain of lines during the transition from pediatric charts to adult charts.