The present invention provides a preservative free ophthalmic formulation. In particular, the ophthalmic formulations of the invention are aqueous formulations comprising nanoemulsion of oil. The present invention also provides a method for treating an eye disorder. In one particular embodiment, the invention provides methods for treating dry eye syndrome using an preservative free formulation comprising a nanoemulsion of oil and alpha 2 adrenergic agonist, pharmaceutically acceptable salt thereof or a mixture thereof. In particular, the alpha 2 adrenergic agonist of the invention has a higher alpha 2A agonist activity compared to alpha 2B agonist activity. This invention also provides a preservative free ophthalmic composition comprising a nanoemulsion of oil, a therapeutically effective amount of an alpha 2 adrenergic agonist, a pharmaceutically acceptable salt thereof or a combination thereof as an active ingredient for treating a dry eye syndrome.
