[Charles Bonnet syndrome: report of three cases].

Charles Bonnet syndrome is characterized by the presence of visual hallucinations associated with loss of vision. We report three patients aged 74, 84 and 80 years (two women) with a severe loss of vision due to ocular diseases and silent visual hallucinations, that they recognized as unreal. Two patients felt that the hallucinations were ominous. Years later, two suffered a probable Alzheimer's disease (AD). One of them had a mild cognitive impairment when the syndrome appeared, that evolved into an AD with psychosis. This syndrome is not uncommon in older patients with loss of vision and it is probably underdiagnosed. Its pathogenesis is probably a cortical deafferentation. The content of the visual hallucinations (faces, landscaped, and so on) coincides with the activation of different areas of the visual association cortices.