A capsulotomy (rarely known as cystotomy) is a procedure to open a portion of the lens capsule, using an instrument called a cystotome.[18] An anterior capsulotomy refers to the opening of the front portion of the lens capsule, whereas a posterior capsulotomy refers to the opening of the back portion of the lens capsule. In phacoemulsification, the surgeon performs an anterior continuous curvilinear capsulorhexis, to create a round and smooth opening through which the lens nucleus can be emulsified and the intraocular lens implant inserted.