Disclosed herein is an ocular drug delivery system, comprising a positively charged chitosan-modified hydrogel, a secretory phospholipase A2 (sPLA2) hydrolysable liposome encapsulating an anti-inflammatory drug and having a negative surface charge, a first thiolated hyaluronic acid (HA-SH) nanoparticle encapsulating a wound-healing drug and having a negative surface charge, and a second HA-SH nanoparticle encapsulating a transforming growth factor-β inhibitor and having a negative surface charge. The sPLA2 hydrolysable liposome and the first and second HA-SH nanoparticles are attached to the positively charged chitosan-modified hydrogel by electrostatic attraction. Uses of the system are also disclosed.