The book provides a detailed description in color format of the optic nerve head changes that occur in glaucoma. It explains the normal and variant anatomy of an optic nerve head and why certain discs are more or less likely to develop glaucomatous changes. This book attempts to explain the anatomical basis of common and not so common signs seen in optic nerve head and retinal nerve fibre layer as captured by a digital fundus imaging system and optical coherence tomography. It also includes optic nerve head conditions mimicking glaucoma. The book is relevant for practicing ophthalmologists, vision science researchers, clinical optometrists, postgraduate residents in ophthalmology, sub-specialty fellows as well as general ophthalmologists, neurologists and neurosurgeons.