Over the past thirty years, much has been learned about the physiological basis for amblyopia. For many years amblyopia was considered to be a retinal disorder; it has now been well established through animal studies that amblyopia represents functional and morphological effects of visual deprivation on the visual cortex and the lateral geniculate nucleus. With this knowledge has come the recognition of a "sensitive period" of development of the visual system, during which time visual deprivation causes amblyopia. The best approach to managing amblyopia is to detect amblyogenic factors before the age of two years and prevent it through eliminating the causes of visual deprivation. When amblyopia exists, it can be cured if adequately treated in children less than 6-7 years of age. Even in older patients, visual improvement can be achieved with therapy. Current research is aimed at developing substances and delivery modes that will allow the sensitive period of visual development to be manipulated, increasing the period during which it can develop and enhancing preventative and therapeutic measures. In this review selected literature contributing to current understanding of causes, prevention and treatment of amblyopia is discussed. Although many new treatment modalities have been tried, occlusion still seems to be the most successful therapy.