Alzheimer's disease (AD) is the most common neurodegenerative disease-causing dementia. The severity of symptoms determines the diagnosis of AD, although an accurate diagnosis can only be made postmortem. Neuropsychological testing is the «gold standard» for early diagnosis of AD, but is time-consuming, does not allow a complete diagnosis with complete accuracy, is highly dependent on the correctness of the tests, and is rather an adjunct to the examination of the patient. Lumbar puncture and positron emission tomography are not available for routine screening of the population. Because the eye is an extension of the central nervous system, the study of its changes may lead to the development of a number of non-invasive differential diagnostic tests to identify patients with AD at an early stage. In recent years, the advent of quantifiable high-resolution imaging techniques that are non-invasive, rapid, and widely available has opened up a new field of ocular-neural imaging. In this paper, we review current foreign and domestic studies of some ocular biomarkers and the methods that could potentially be used in the early diagnosis of Alzheimer's disease.