This is a comprehensive textbook addressing the unique aspects of drug development for ophthalmic use. Beginning with a perspective on anatomy and physiology of the eye, the book provides a critical appraisal of principles that underlie ocular drug product development. The coverage encompasses topical and intraocular formulations, small molecules and biologics (including protein and gene therapies), conventional formulations (including solutions, suspensions, and emulsions), novel formulations (including nanoparticles, microparticles, and hydrogels), devices, and specialty products. Critical elements such as pharmacokinetics, influence of formulation technologies and ingredients, as well as impact of disease conditions on products development are addressed. Products intended for both the front and the back of the eye are discussed with an eye towards future advances.