This document discusses viscoelastics used in ophthalmic surgery to protect ocular tissues, manipulate tissues, and maintain space during surgery. It describes the characteristics, polymer structures, and types of common viscoelastics including hydroxypropylmethylcellulose, hyaluronic acid, and chondroitin sulfate. The document emphasizes that total washing out of viscoelastics, especially high molecular weight cohesive types, is important to prevent postoperative complications like increased intraocular pressure. No single viscoelastic is ideal for all cases so surgeons should choose ones suitable for their technique.