This chapter offers a visual examination of the pathology and progression of diseases such as keratoconus, pellucid marginal degeneration, and keratoglobus. Through detailed imagery, the atlas depicts the characteristic corneal thinning and conical protrusion found in keratoconus, including subtle early signs and advanced corneal scarring. Pellucid marginal degeneration is illustrated with its distinctive peripheral band of thinning, aiding clinicians in differential diagnosis. Keratoglobus is presented through images that capture the diffuse thinning and globular protrusion of the cornea. This chapter allows for a deep dive into the phenotypic presentations and diagnostic features of these conditions, providing a vital visual resource for both educational and clinical purposes. For each ectatic disorder, the atlas emphasizes morphological cues essential for diagnosis, progression monitoring, and surgical planning, particularly for corneal transplantation and collagen cross-linking procedures.