Ophthalmic drug delivery is one of the most interesting and challenging endeavours facing the pharmaceutical scientists, the major problem encountered to pharmaceutical scientist is rapid precorneal elimination of the drug, resulting in poor bioavailability and therapeutic response, because of high tear fluid turn over and dynamics. Newer research in ophthalmic drug delivery system is directed towards amalgamation of several drug delivery technologies which helps to extend the contact of the vehicle at the surface of the ocular system and slows down the removal of the drug. In situ-forming gels are liquid upon instillation and undergo phase transition in the ocular cul-de-sac to form visco-elastic gel and these gels provide a response to environmental changes. In the past few years, an impressive number of novel temperature, pH, and ion induced in situ forming systems have been reported for sustained ophthalmic drug delivery. This review includes polymeric systems used in various temperatures, pH, and ion induced in situ gel formulation to achieve prolonged contact time of drugs with the cornea and increase their bioavailability.