The Alzheimer's disease (AD) is a common neurodegenerative disease among the elderly population with the memory impairment as the initial symptom, gradually followed by the progressive cognitive impairment and the behavioral and psychological symptoms, with heavy economic and care burdens to both family and society. The early symptoms of the AD are not obvious, which causes the poor therapeutic effect after diagnosis, thus early diagnosis is particularly important. Increasing investigations identified the visual impairment in the AD patients, but with no epidemiological data of the AD accompanied with the visual impairment. This paper mainly focuses on the clinical symptoms, the mechanism, the detection and the evaluation approaches of the visual impairment, including the optical coherence tomography, the visual evoked potential, the retinal microvascular examination and the neuroimaging so as to systemically assess the visual impairment, explore the specific, sensitive and simple methods of evaluation of the AD and provide evidence for early diagnosis and intervention of the AD. Comprehensive management of the AD includes non-drug intervention and drug therapy, however, the treatment of the visual impairment in the AD is an important issue.
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