OK, well regardless of theory, this was before :
These are my tools :
This is after :
20 min process but only five mins of work.
Are they perfect ? No.
Are they a massive improvement and pretty good for two year old pool goggles ? Yep 
I could have made the second picture look much better but I tried to be as fair as possible. Maybe another scrub would have helped but to me it was unnessasry, to look though the goggles now you would think they are new (I have a new spare pair for comparison).
It’s maybe the fourth time (possibly fifth) those goggles have gone through that process. Other than that, after each use they are rinsed under the shower and then stored in the microfibre bag they came with. Other than my eyelashes, nothing touches the inside of the lenses until they get a deep clean as per the above.
Please consider I am not trying to be argumentative here, I am just posting up my circumstances and experiences. Hopefully it’s of use and the OP will also see a worthwhile improvement …
WD