The present book differs significantly in its arrangement and treatment of the material from most ophthalmology textbooks. The textbook, which the medical student uses during their university years, later serves as a guide and reference book when they enter practical work as a doctor. The intention to make the book suitable for this purpose has led me to elaborate on it. It does not aim for completeness, as it is not intended for specialized ophthalmologists, who have larger manuals and compilations available to them. Rather, it is meant to assist the practicing physician in difficult cases. The task of a textbook is not to present as much information as possible, but to explain what is essential to know in the most understandable form.