The type of viscoelastic device used depends on its intended purpose. A dispersive substance will coat the endothelium better to provide protection to the cells whereas a cohesive substance will fill space to allow room for intracameral manipulation. Insertion of the cannula and injection of the viscoelastic device requires care to avoid damage to surrounding structures and well as providing important signs to how the eye will respond to the phacoemulsification process. It has as much importance as any instrument and can be utiised at various stages of the surgery. Thorough removal at the end of the case needs to be performed to reduce the occurrence of early postoperative pressure spikes.