This new fourth edition has now been fully revised and updated in line with current curricula, key research developments and clinical best practice. It succinctly incorporates the massive strides being made by genetics and functional genomics based on the Human Genome Project, the new understanding of how the microbiome affects all aspects of immunology, the remarkable progress in imaging technology now applied to anatomy and neurophysiology, as well as exciting new molecular and other diagnostic methodologies now being used in microbiology and pathology. All this and more collectively brings a wealth of new knowledge to students and practitioners in the fields of ophthalmology and visual science.