As a son of a dementia sufferer I know how important it is to provide an environment that is safe and stimulating for a dementia patient. The Dementia Center at Stirling University is doing some great work looking at the importance of lighting for people like my mum.
The eye sends signals which the different parts of the brain interpret to form a visual construct. Therefore some older people with dementia are significantly disadvantaged compared to other older people because the ability of the brain affected by dementia to process visual signals is greatly diminished. Therefore it is even more important that higher light levels are delivered into the environment of people with dementia in order that their brain has some chance of performing reasonably.