This study was to investigate the feasibility of frequency doubling technology (FDT) visual field testing in Alzheimer's disease (AD) in order to identify early biomarkers of AD in patients already diagnosed with AD and compare the findings to participants not having Alzheimer's disease. This biomarker would be useful in a battery of tests for the early identification of those with AD. It was not the intent to correlate the visual system biomarker with severity of disease, but to determine if the biomarker was present in pass or fail screening criteria. The study showed with very strong significance that the FDT can identify biomarkers of those with AD compared to an age-matched population that does not have AD. FDT is a simple test to take and administer and has been used to screen for eye and retinal diseases such as glaucoma, retinal macular degeneration, and diabetic retinopathy. The results obtained in the FDT readout are analyzed and compared to the age normative database within the system. The FDT ability to screen for AD biomarker in the visual system was significant in those with AD compared to the controls, and the deficits were not related to any ocular pathology.