(5" x 5") Patti Pics optotype chart flip book for vision testing. Single presentation book is great for pediatric screenings in the school setting. Designed and utilized for children ages 19-36 months. This 13 page spiral bound Single Symbol Presentation book is great for pediatric and preliterate school screenings. Each page features arranged, recognizable optotypes for easy masking during testing. Single Symbol Presentation book is a key for detecting signs of Amblyopia.