Section 4 presents materials in two parts: Part I, Ophthalmic Pathology; and Part II, Intraocular Tumors. Part I uses a hierarchy that moves from general to specific to help derive a differential diagnosis for a specific tissue. Part II is a compilation of selected clinical aspects of importance to the general ophthalmologist. Additionally, this section has a variety of images and videos. Both print and eBook users have access to the videos. Upon completion of Section 4, readers should be able to: *Describe a structured approach to understanding major ocular conditions based on a hierarchical framework of topography, disease process, general diagnosis and differential diagnosis; *Summarize the steps in handling ocular specimens for pathologic study, including obtaining, dissecting, processing, and staining tissues; *Identify those ophthalmic lesions that indicate systemic disease and are potentially life threatening. // Last major revision: 2016 2017 // About the BCSC: The Academy's Basic and Clinical Science CourseTM is ophthalmology s definitive source of clinical information. Practicing ophthalmologists and residents worldwide use the BCSC® to ensure the highest-quality patient care. Stay current with the ophthalmic reference that is vetted by 100+ ophthalmologists every year. Each of the 13 volumes includes up-to-date clinical knowledge, concise information and tables, self-assessment questions with answers, photos and illustrations and opportunities for earning AMA PRA Category 1 CreditTM. // Beginning with the 2013 2014 edition, the Academy and the European Board of Ophthalmology (EBO) have partnered to make the BCSC the standard text for all European ophthalmology training programs. The EBO now recommends the BCSC as the primary educational resource for European trainees and ophthalmologists studying for the annual EBO Diploma Exam. // CME Information: The American Academy of Ophthalmology is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. // The American Academy of Ophthalmology designates this enduring material for a maximum of 10 AMA PRA Category 1 CreditsTM. Physicians should claim only the credit commensurate with the extent of their participation in the activity.