Research on vitreous substitutes has advanced from conventional gases and silicone oils to third-generation biomimetic hydrogels. While existing substitutes provide short-term retinal tamponade, they typically require strict postoperative positioning and carry risks of cataract formation, ocular hypertension, and silicone oil emulsification. These materials therefore fall short of meeting the essential requirements for long-term tissue support, matched physicochemical properties, and high biocompatibility simultaneously. Recently, polymer-based hydrogels have gained prominence as ideal candidates owing to their high water content, optical transparency, adjustable viscoelasticity, and favorable biocompatibility. They have diversified into several forms, including uncrosslinked solutions, preformed hydrogels systems, and in-situ crosslinked systems. Biopolymer hydrogels, such as those derived from hyaluronic acid, collagen, or alginate, demonstrate high safety but often exhibit inadequate mechanical strength and poor stability in vivo. Synthetic polymer hydrogels, including polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone, allow tunable properties yet raise concerns regarding monomer toxicity and degradation-related safety. Future research is shifting from simple material replacement toward functional reconstruction and intelligent regulation. Increasing efforts aim to develop smart hydrogels capable of sustained drug release and cell encapsulation, alongside advanced strategies employing biodegradable scaffolds to promote native vitreous regeneration, with the ultimate goal of achieving full functional restoration.