<s>[INST] context: Lensectomy In this operation most of the lens including anterior and posterior capsule along with anterior vitreous are removed with the help of a vitreous cutter. Childhood cataracts,both congenital/developmental and acquired, being soft are easily dealt with this procedure especially in very young children (less than 2 years of age) in which primary IOL implantation is not planned. Goniotomy Surgical procedure for congenital glaucoma In this procedure a Barkan&;s goniotomy knife is passed through the limbus on the temporal side. Under gonioscopic control the knife is passed across the anterior chamber to the nasal pa of the angle. An incision is made in the angle approximately midway between root of the iris and Schwalbe&;s ring through approximately 75deg. The knife is then withdrawn. Although the procedure may have to be repeated, the eventual success rate is about 85 percent. Phacoemulsification Phacoemulsification is a technique of extracapsular cataract extraction in which after the removal of anterior capsule (by capsulorhexis), the lens nucleus is emulsified and aspirated by the probe of a phacoemulsification machine. IOL Indication : Recent trend is to implant an IOL in each and every case being operated for cataract; unless it is contraindicated. However, operation for unilateral cataract should always be followed by an IOL implantation. [/INST] question: Which is not a cataract surgery- | options: A: Lensectomy B: Goniotomy C: Phacoemulsification D: IOL | answer: B </s>