Alzheimer's disease(AD), a neurodegenerative disease, can result in memory loss,cognitive and behavioral deficits. The pathological hallmarkes are β amyloid plaques and neurofibrillary tangles which lead loss of neurons in brain. As the extension of the central nervous system, retina has a similar tissue anatomy with central nervous system. The β amyloid plaques have also been detected in retina of AD. Furthermore, according to eye examinations of AD patients, we have found the loss of retinal ganglion cells, the attenuation of retinal nerve fiber layer thickness, the smaller changes of macula lutea, the decline of vascular density and so on. And then, there occurs the visual field loss and the decline of contrast sensitivity and so on in AD patients. Thus, the retina has occurred nerve degenerative changes in AD. Meanwhile, there has been proved that the retina nerve degeneration is even earlier than senile plaques formation in brain. In addition,curcumin, a natural and safe fluorescent dye, can be used to label β amyloid plaques in retina. The above suggests that retina can be a window for the early diagnosis of AD.