This is a prospective double-masked, randomized controlled trial which evaluates central visual field function as it relates to macular pigment optical density, contrast sensitivity, and dermal carotenoid levels in the presence of a commercial macular pigment-containing medical food (Lumega-Z). Participants will be randomized to twelve weeks of supplement + dorzolamide or twelve weeks of placebo. All packaging of supplement and dorzolamide and the placebo will be identical and distributed by a third party. Both subjects and the investigators examining patients will be masked to placebo and experimental group assignment.