During the process of phacoemulsification, the capsular bag can be damaged, resulting in dislocation of pieces of nucleus into the vitreous.  When this occurs early in the nucleus removal, it is possible to use a ViscoPAL or viscoelastic posterior assisted levitation of the pieces, to avert the need for a pars plana vitrectomy and fragmatome.  It needs to be done carefully as excessive manipulation of the vitreous base can result in retinal tears and potential for detachment.