Eye is a complex organ responsible for vision with its unique anatomy and physiology. Conventional routes for ocular drug delivery include topical, subconjunctival, intracameral, intravitreal, transscleral, retrobulbar, and systemic. Among them, topical route is one of the preferred routes due to its non-invasiveness, safety, and high patient compliance. However, presence of various anatomical and physiological ocular barriers creates hindrance in active absorption and activity of therapeutic drugs to treat ocular diseases by any route. To overcome various ocular barriers and improve drug bioavailability, development of nanotechnology-based ocular drug delivery system (ODDS) is advantageous. Ocular treatment is achieving the higher level with several advantages due to advancement in nanocarriers. Nanostructured platforms have several positive outcomes, including overcoming ocular barriers, increasing transcorneal permeability, lengthening drug residence time, reducing drug degradation, decreasing dosing frequency, achieving sustained release, improving patient compliance, drug targeting, and gene delivery. Many nanocarriers, such as nanoparticles, nanosuspensions, nanomicelles, nanofibers, nanoemulsions, liposomes, etc., have proven excellent delivery potential in both in-vitro and in-vivo studies, enhancing drug permeability across the ocular barriers and increasing drug bioavailability in the eye. In future, more innovations are needed to achieve greater results in management of ocular diseases.