Compositions and methods for treating glaucoma by restoring the filtration capabilities of the endothelial lining of Schlemm's canal are provided. More particularly, methods of lowering intraocular pressure are disclosed, where a subject in need of such treatment is administered a therapeutically effective amount of a composition. In various embodiments, the composition may include tyrosine or L-DOPA conjugated to an ascorbic acid, an enzyme, a nucleic acid encoding an enzyme, or trabecular meshwork cells.
