The vitreous is an inert, transparent, colorless, hydrophilic gelatinous structure that fills the space between the lens and the retina. It maintains the intra ocular pressure and is important in maintaining transparency of the media for maximum photon transmission to the retina. With advancing age the vitreous undergoes liquefaction resulting in its transformation from a formed gel form to fluid form. Vitreous substitutes or the so called tamponading agents are used in vitreo-retinal surgery to restore intraocular pressure and provide intraocular tamponed. The type of substitute used is dependent on the individual clinical situation. The proper vitreous substitute for long-term drug delivery system should either reduce or eliminate the need for multiple intravitreal injections.
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