A method for sustained delivery of an agent to an ocular organ in a subject, comprising topically delivering to the ocular surface a liquid thermoresponsive hydrogel comprising agent-loaded polymer microparticles, wherein the agent is an antibody, a fusion protein, a chemokine, an interleukin, a growth factor, albumin, immunoglobulin, an interferon, a peptide, stem cell-conditioned media, plasma or serum.