Book excerpt: Completely updated, revised, and redesigned, this edition includes all of the features that have made it so successful in the past, such as succinct understandable definitions, extensive tables and illustrations, and practical clinical advice. Plus, it now includes many new entries on pathology, pharmacology, investigative techniques, refractive surgery, contact lenses and visual perception. Over 5400 terms are included. Tables and helpful illustrations help users understand important concepts and terms. Foundation information is offered on essential areas such as basic sciences, optics, and refraction. Practical clinical advice included with many definitions. New entries covering ocular pathology, ocular pharmacology and therapeutics; ocular anatomy and basic sciences; investigative techniques; psychology of vision; and visual perception. Thoroughly updated to include the latest information on topics relevant to the optometric profession. New tables and illustrations highlight and clarify key concepts.