An ideal viscoelastic should be inert, iso-osmotic, have high viscosity, non pyrogenic, optically clear, and possess pseudo plasticity. Viscoelastics may be cohesive with high viscosity which provide more space (e.g. hyaluronic acid) frequently used but expensive or may be dispersive (low viscosity) which coat the surface well (e.g. methyl cellulose) and more commonly used. Others are chondroitin sulphate, polyacrylamide, poly- TEGMA. They are used is cataract surgery to maintain deep A.C, combat vitreous up thrust, facilitate in-the-bag IOL insertion, protect corneal endothelium and facilitate viscodissection. Their main complications include elevation of intra ocular pressure, corneal endothelial toxicity, inflammation and fixed dilated pupil.