NEW YORK: In patients aged 50 and above, reading disturbances are a frequent complaint, generally the origin of which is clear following a thorough ophthalmological exam.
However, visual disturbances can also be a symptom of progressive dementia. Differentiating between dementia and another origin is based on clinical presentation, evolution, neuroradiological results, and sometimes results of brain biopsy.
Alzheimer’s disease (AD) is the most common neurodegenerative disease, accounting for 50–65 % of all cases of dementia. Visual impairment has previously been reported in AD, generally with advanced disease and severe cognitive impairment. Visual impairment in AD is understood to result from visual cortical involvement by neurofibrillary tangles and plaques, and include homonymous hemianopia, visual agnosia and Balint syndrome.
Furthermore, progressive neural tissue loss in the retina (retinal ganglion cells) may contribute to the visual symptoms and visual loss in AD.