Here is a trick that I have adapted while I was diving up in Alaska last year.
I usually wear cheaters when welding topside so with that said I needed to adapt cheaters to my u/w welding lens holder heres what I did. I use a lens holder made of brass so I first took out the spring that holds the welding lens in place then I put a plastic cheater next to it and simply scratched a line 360 degrees around the outside of the cheater lens. Next I took out the lens and got a p-grinder with a cutting disc and cut a grove in the brass lens holder big enough to hold the retaining spring holder after that was done re-installed the welding lens with the cheater lens right up next to it and put in the retaining spring and Man ! what a difference. Try it its a real quick fix with a life time of benefits. Dive Safe.