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.
