A 69-year-old woman developed a rapid and severe visual loss and became nearly blind in a few weeks. As she also presented with memory loss and other disturbances of cognitive functions, with progressive deterioration over one year, a probable Alzheimer's disease was diagnosed. Cerebral CT scan and magnetic resonance imaging were normal. However, clinical and electrophysiological (visual evoked potentials) data indicated an impairment of the primary visual pathways rather than a degeneration of the secondary visual cortex. This case is compared with and discussed in relation to recent reports concerning retinal and optic nerve damage in Alzheimer's disease.