They make visor inserts for near sighted correction....or so ive heard
. Check out a welding supply store.
Also known as a cheater lens. I got one off ebay. Even though I have corrective lenses, this acts to magnify the puddle even better which is really useful for Tig welding. (or any type welding I suppose) Most but NOT all helmets have a bracket for this lens to slip in. If not, duct tape?
The only trick is deciding which one to get! They are sold in different "diopters" which is the strength. Some say to go to a store and try on reading glasses until you find one that works for you and see what diopter they are. I just chose something mid range like a 2.0 or something and really improved things.
Here's what they look like: