The opthalmic nanoemulsion drug delivery system is novel and advanced modes of drug delivery system. Nanoemulsions are oil in water type of emulsion and water in oil type of emulsion. The diameter of the drops range are 50 -1000nm (109m). The droplet size average range between 100-500nm. It is a part of widespread class of colloidal dispersion of multiphase. Nanoemulsions are accessible to formulate and upscale, and they appear high volatility in their constituents. They have turn out very feasible, cost effective, and non- invasive nanocarriers for intensify opthalmic delivery of a wide range of active compounds that influence to metabolize heavily or suffer from undesirable side effect when taken orally. In addition, the anti-viral and antimicrobial properties of nanoemulsion components, prominent to preservative free formulation, develop nanoemulsion very enticing path for ocular drug delivery. Thus the aim of this article is spotlight on nanoemulsion, various methods of preparation, characterization techniques, Also focus the mechanisms and strategies accomplished to effectively deliver drugs, both oil and water and water in oil nanoemulsion types, via the ocular way. The methods will be used to prepare for nanoemulsion are high energy method such as: high pressure Homoginization, Ultrasonication, Microfluidization. Evaluation parameters will be include particle size analysis, rheological measurement, refractive index, surface tension, viscosity, therapeutic efficacy study, in vitro release study and ocular irritation study respectively.