The present invention is directed to a method of reducing intraocular pressure. The method comprises administering to a subject a pharmaceutical composition comprising an effective amount of a purinerginic receptor ligand, which is a mononucleoside polyphosphate or dinucleoside polyphosphate defined by general Formula I. The method of the present invention is useful in the treatment or prevention of ocular hypertension, such as glaucoma, including primary and secondary glaucoma. The method can be used alone to reduce intraocular pressure. The method can also be used in conjunction with other therapeutic agents or adjunctive therapy commonly used to treat glaucoma to enhance the therapeutic effect of reducing the intraocular pressure.