Section 11 of the Academy's Basic and Clinical Science Course (TM) (BCSC (R)) reviews the anatomy, physiology, and pathology of the lens. This section covers the epidemiology, evaluation, and management of cataract and gives an overview of cataract surgery, including in special situations. In addition, Section 11 provides appropriate differential diagnoses and management plans for intraoperative and postoperative complications of cataract surgery. BCSC Section 11 includes a new discussion of sustainable cataract surgery and expanded discussion of preoperative considerations for cataract surgery, in particular the range and benefits of various intraocular lens designs. Key takeaways are highlighted at the beginning of every chapter. This edition contains over 200 images, and several new and revised figures show surgical tools and methods of cataract removal. 42 videos of surgical procedures and two animations explore the embryology, biochemistry, and physiology of the lens. This edition includes three new interactive case studies on refractive target selection, toric lens selection, and post-refractive surgery IOL power selection. About the BCSC The Academy's Basic and Clinical Science Course (TM) is ophthalmology's definitive source of clinical information. Practicing ophthalmologists and residents worldwide use the BCSC (R) to ensure the highest-quality patient care.