The Theory of Ocular Defects and of Spectacles is a book written by Hermann Scheffler and originally published in 1869. The book provides a comprehensive explanation of the various defects of the eye and the use of spectacles as a remedy for these defects. Scheffler's work is based on his extensive research and observations of the human eye, and his theories and explanations are presented in a clear and concise manner.The book is divided into two...