Disclosed herein are methods for decreasing or attenuating an increase in capillary permeability in the retina in a subject in need of such treatment, comprising administering a composition comprising an amount of a phthalazine derivative or a salt thereof to a subject suffering from excessive or pathological capillary permeability in the retina, the amount of phthalazine derivative or salt thereof being effective to decrease the permeability of capillaries in the retina of the subject.