What I noticed was vision affects when touching steel the ground was attached to as I welded a large structure with significant DC amperage without gloves, so also contacting the stinger and being part of the circuit. I have undertaken to avoid being part of such circuits since I noticed it, and hope that is all that is necessary to avoid that affect or it's consequences going forward, as that's really all I can do besides not welding anymore.

I've always been amazed that DC has so little affect on us, while causing such dramatic physical effects on metal. It appears I underestimated the affects it had on me all along. It's still an amazing dichotomy to me, however.