Inhibition of geranylgeranylation of Rho GTPases and heterotrimeric G-proteins in the aqueous outflow pathway increases aqueous humor outflow, possibly through the tissue relaxation, and through altered cell adhesive interactions and actin cytoskeletal organization in cells of the outflow pathway. In addition, such inhibition is useful for treating age-related macular degeneration. The GGTase-I enzyme is a molecular target for lowering increased ocular pressure in glaucoma patients.