The invention relates to compositions and methods that utilize polymeric nanoparticles to deliver a therapeutic compound to ocular cells or ocular tissue. Provided is a drug-loaded micelle comprising self-assembled amphiphilic biopolymers, such as hydrophobically modified nucleic acids or polypeptides, for use as ophthalmic drug delivery system. Also provided are ophthalmic compositions and methods for preventing or treating an ophthalmic disease.