Viscoelastic are substances with dual properties having a fluid's viscosity and elasticity of a gel or a solid. Viscoelastics have revolutionized modern-day cataract surgery because of their viscous, elastic, and pseudo-plastic properties. They are also called ophthalmic viscosurgical devices (OVD), introduced by the International Standards Organization (ISO). Sodium hyaluronate was the first viscoelastic introduced in 1972 as a substitute for aqueous and vitreous humor, and these compounds are an essential component of ocular surgery. This activity reviews the indications, contraindications, anatomical source, classification, properties, complications, and clinical significance of viscoelastics.