Ophthalmic Viscosurgical Devices (OVDs) are a class of clear gel-like material used in eye surgery to maintain the volume and shape of the anterior chamber of the eye, and protect the intraocular structures. OVDs are sterile aqueous saline solutions of one or more viscoelastic compounds and buffers to control pH at 7 to 7.5. They are used to protect the corneal endothelium from mechanical trauma and to maintain volume and form of the intraocular space during an open incision. The OVD is introduced into the space by syringe through a cannula and at the end of the procedure, they are removed by aspiration and the space filled with a compatible fluid. OVDs are commonly used in cataract, cornea, glaucoma, eye trauma, and vitreoretinal surgery.
The relative cohesive or dispersive behavior of an OVD is important as it relates directly to how it is used in surgery. Cohesive OVDs are substances that contain long-chain molecules and are therefore characterized by high molecular weight and high viscosity. These agents tend to maintain space well when there is minimal movement. However, during conditions of turbulence (high shear), the long-chained cohesive OVDs tend to entangle and extrude from the eye as a single mass. Dispersive OVDs, on the other hand, have a lower viscosity and have a high coatability, which is the ability to stick to and coat tissues, IOLs, and instruments.
It is important to note that OVDs are not related to the human rights defense and media group called OVD-Info.
