I have written before about the fact that shared streets are felt to be safer, because the doubt of right-of-way causes all the road users to be more cautious about their travel along the road.
I have to admit to my shame I had not considered those road users with eyesight problems, but I think that there is a solution to give both the partially sighted and blind a definitive kerb without removing the benefits of having shared street space.
Perhaps the solution would be along similar line to the raised pavement areas at crossings. The raised ‘bumps’ allow a blind person to feel the change and follow the ‘bumps’ to the road edge. This type of edge definition would serve the blind without giving the drivers of vehicles the confidence to drive in an unsafe manner.
There are no perfect solutions, but that might work for all parties.