Ultrasonic cataract extraction is a minimally invasive procedure with a high degree of safety. It has the advantages of small incision, fast healing and good vision recovery. Therefore, it is now used by more than 80% of ophthalmologists in developed countries. The procedure involves cataract removal and IOL implantation through a 3C5mm scleral incision using an ultrasound emulsifier. Its advantages are: small incision, less tissue damage, well maintained anterior chamber, short operation time, fast vision recovery, stable refractive status, and small corneal astigmatism.