This document discusses various indications and techniques for lens surgery. It covers two main categories of lens surgery: medical and optical/refractive. Medical indications include lenticular opacification, malposition, malformation, and inflammation. Techniques are discussed such as intracapsular extraction, extracapsular extraction, and phacoemulsification. The history of cataract surgery techniques from ancient times to modern techniques like femtosecond laser-assisted surgery is also summarized. Specific topics like capsulorrhexis, presbyopia surgery, astigmatism correction, and references are also outlined.