Thinking of quitting due to dangerous driving
A few suggestions:


Get some training. This will cover things like correct road positioning, which can make a big difference to how other road users interact with you.
Try quieter routes or cycling at different times of day when there is less traffic around. This cycle route planner will help with routes.
Try to find other people to cycle with. Cycling in a group is much less intimidating, but even one other person should make a difference.
I use a mirror which helps to keep track of what's behind me. I don't know if that would work for someone who is partially sighted, but it's probably worth trying.


It's also worth remembering that the majority of cycling accidents occur at junctions. It's relatively rare for a car to drive into the back of the cyclist.