Research published in the Jama Ophthalmology journal has suggested that up to one in five cases of dementia in older people might be avoided if problems with eyesight are prevented or treated.
Vision loss was highlighted as a modifiable risk factor in the recently updated Lancet Commission study on risk factors https://journalofdementiacare.co.uk/the-lancet-risk-factors-for-dementia, suggesting 2% of dementia cases were attributable to untreated vision loss in later life. However, this new research, using data from people in the US, suggests up to 19% of dementia cases could be due to visual impairments.
You can read this latest research here: https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2823286