Patti Pics have been developed for pediatric testing and are calibrated to Sloan standards. Each optotype follows a strict criteria. Each symbol has equal difficulty and blur at threshold. Also, the size of each symbol is based from the Snellen 5×5 grid principle. All Patti Pics symbols are easily recognizable and have high testability. Furthermore, Patti Pics make the transition from pediatric tests to adult tests easier, since they are based from the same standards as the adult tests. Mistaken loss or gain of lines is minimized. Patti Pics symbols are great for pediatric testing and are highly reliable.