Hydrocinnamate compounds that exhibit proteasome modulation activity, and in particular, proteasome inhibitory activity, can be used to topically or systemically treat ocular disorders associated with proteasome activity. The hydrocinnamate compounds can be applied to the eye, in any of a variety of ocular formulations, to treat ocular disorders, such as ocular rosacea, diabetic retinopathy, macular degeneration, and dry eye. The hydrocinnamate compounds can also be administered systemically to treat ocular disorders.