The Importance of Vision in Design

I try to consider so many different aspects, especially vision, like vision impairment and also like physical, physical bodies. There's just, there's a lot of little things people don't think about. One thing that comes to mind is on sidewalks, you have to have an area that like dips down. Like if a design is like way up in the air, like someone like my dad who is sitting in a chair won't be able to read it as well as someone who is standing upright. Tied it back into design.