| Description | Accepted by leading authorities as a simple and accurate method for discovering congenital color blindness of two type total color blindness and red/green blindness. This book is used for children and the illiterate. | Accepted by leading authorities as a simple and accurate method for discovering congenital color blindness of two type total color blindness and red/green blindness. This book is used for children and the illiterate. | Accepted by leading authorities as a simple and accurate method for discovering congenital color blindness of two type total color blindness and red/green blindness. This book is used for children and the illiterate. | Accepted by leading authorities as a simple and accurate method for discovering congenital color blindness of two type total color blindness and red/green blindness. This book is used for children and the illiterate. |