FIELD : medicine. SUBSTANCE : group of inventions relates to the field of medicine, namely to ophthalmology, and is intended for treatment of a disease or condition of the posterior segment of the eye. In the method, the local aqueous preparation contains a pharmaceutically active amount of a steroid and a thermodynamically stable, self-forming liposome formed from a PEG-based lipid, where the percentage by weight of lipid is less than 20? by weight of the total weight of the preparation. Said steroid is a triamcinolone acetonide. In another embodiment, a topical ophthalmic preparation for treating the posterior segment of the eye is disclosed, comprising a thermodynamically stable, self-forming liposome having a chain of polyethylene glycol (PEG) and a glycerol backbone, triamcinolone acetonide, a surfactant and a buffering agent. In yet another embodiment, the self-forming, thermodynamically stable liposome contains a PEG-based lipid conjugate selected from the diacylglycerol-PEG compound, where the conjugate has a melting point below about 40牥C, and the length of the acyl chain is greater than or equal to 14 carbon atoms, and the PEG chain has a molecular weight of between about 300 and 5, 000 Dalton. Also provided is a method for treating a disease of the posterior segment of the eye in a patient in need of such treatment, including local administration to the eye surface of a pharmaceutically effective amount of a local ophthalmic preparation containing a thermodynamically stable, self-forming liposome formed from a PEG lipid and triamcinolone acetonide. EFFECT : use of a group of inventions provides treatment of a disease or condition of the posterior segment of the eye by local administration. 20 cl, 1 tbl, 7 dwg, 4 ex