Grant here. I am legally blind (10% of left eye ramaining) according to the social security folks, and a Disabled veteran to boot!
I ride a Sun USX HD20 Recumbent trike with electric assist. Living in WA state I do lots of riding in raingear and have had to waterproof everything electrical
BTW, if you are riding a heavy machine downhill in the rain using rim brakes better get ready to drag your feet!
Both of my knees are bone to bone with multiple surgeries and strangely enough I can ride the recumbent with virtually NO knee pain!