The history and development of vision and ocular medicine over time always occurred within a framework of many other cultural events. Thus, it is important to understand these factors before one can appreciate how vision and ocular medicine were viewed and practiced at a particular time and in a particular region, and how both slowly progressed over the centuries.Ocular medicine is, and always has been, a part of medicine, and is influenced by its theoretical and practical principles, as well as its diagnostic and therapeutic practices. If the ancient people thought that diseases were caused by divine causes, then this was first applied to the body, but later on transferred to the eye. If medications proved beneficial to the body they would in turn be used to treat ocular problems.The state of scientific knowledge affected how vision was thought to occur and how ocular medicine could help to maintain healthy vision and how to restore normal sight when it became impaired. Only knowledge of the nature of light and its properties of refraction by different transparent objects allowed scientists to understand the optical processes which occur in the eye. These recognitions led to the use of spectacles and ultimately to the latest surgical procedures like Lasik to improve vision. Advances in the natural sciences have slowly turned an empirical into a scientific medicine, with chemistry, physiology, molecular biology, microbiology, genetics and other specialties now prominently shaping medical thinking and practice, leading to more sophisticated diagnostic and therapeutic procedures for the body and the eye.Sciences and medicine in turn have been influenced by many factors, such as religion and superstition, in particular in the early periods of human history. If religion forbade dissections of the human body, then knowledge about the basic structures of the body and the eye had to remain obscure. This lack of knowledge was not due to a lack of scientific curiosity by medical scholars, but dictated by religious doctrines. Similarly, superstition and the belief in supernatural forces, other than divinity, shaped markedly the practice of medicine, and physicians had to incorporate such thinking into medical theories and the treatment of their patients.Science and medicine are influenced by political events. Wars, revolutions and persecutions can affect science and medicine in many ways. During wars, scientific and medical research is usually halted and many universities, research laboratories, hospitals and libraries with their valuable texts may be destroyed. One could also assume that many promising young men and women die prematurely and so never rise to their full potentials. On the contrary, wounds and dismembered bodies allowed physicians, who were forbidden to dissect corpses, an insight into the anatomy and physiology of the human body, including the eye and its functioning.Culture, tradition and prior knowledge influences sometimes helpfully, but mostly in a detrimental fashion progress in medicine. Of course, prior knowledge is the basis of further knowledge, since knowledge is accumulated in a stepwise progression. One scientific and medical finding will lead to another, mostly to a more sophisticated finding. In contrast, rigid and inflexible tradition can stifle further developments. For example, the authorative texts written by Galen gave the impression that everything was known and no further medical research was needed. These writings delayed progress in medicine, vision research and ocular medicine by a thousand years. Likewise, the suggestion by Semmelweis that physicians should wash their hands before touching the patient or performing surgery was ridiculed by the medical establishment, and traditional physicians continued their old practices, inflicting unnecessary harm on their patients.Economics, or the availability of money, can facilitate progress in the sciences, medicine and surgery. A wealthy government can provide research money to support scientific and medical research, as well as train promising young minds for future careers in medicine or the sciences. It will also provide health insurance, so that even the poor can benefit from the results of such progress.Geographical location and expansions in the past, or the inter-actions among countries that occur today, do not only foster trade relationships and stimulate the economy, but also affect medicine in a broad sense. Warmer climates breed more insect-carrying diseases of the body and the eye. Interactions among different civilizations not only facilitate the exchange of medical information from different areas but, unfortunately, also increase the spread of infectious diseases which were once confined to isolated areas.Finally, the authors tried to incorporate as much as possible of the actual translations of the optical and medical texts into the individual chapters - denoted in italics - to provide the reader with a feeling of the original (albeit translated) levels of knowledge, and ways of thinking and reasoning.Thus, the authors started each chapter with a brief description of the historical, political, religious, social, scientific and cultural environments of a particular time period within a discussed society. This is followed by a brief description of general medicine to give a basic understanding of the medical thinking and practice of that time, and continues with a description of the state of the knowledge of vision and the theory and practice of ocular medicine during specific time periods and among selected civilizations. Here, the authors arbitrarily chose those civilizations which historically had the most impact on vision and ocular medicine in the Western World and the USA. In the epilogue, the authors allowed themselves the liberty of presenting a few personal thoughts and comments.It is hoped that this form of presentation will provide the proper background for understanding and appreciating the history and progression of the science of vision and ocular medicine.