chapter Promoting independence through design of the environment
Another complication is that most people with dementia are older and will have many of the disabilities of old age: yet, they will not understand this and will fail to make allowances. Their eyes, for example, will be less and less able to discriminate between colours, so hindering their ability to make sense of the environment through colour. Designers have to use very strong colour contrast for important features (such as the toilet door). The ability to see three dimensions also deteriorates in many ageing eyes. People with dementia will not be able to adjust to this, which makes it important not to change floor colours, which can be then seen as steps. Glare and reflections are particularly difficult for the ageing eye (Brawley 1997).