I've had the 3 Speedo pairs (2 blue and 1 amber) more than 4 years ago and I've stopped using them because of they got too blurry. I've described this problem in this entry. It got so frustrating that when I lost a black pair which had the same problem, I wasn't too disappointed.
Anyway, the blurring is similar to what happened to my Adidas-Storm goggles below.
On the inside, you can feel the portion to be rough. Of course the pair was all nice and clear when I got them. And so I got frustrated when this happened - just like what happened to the Super Marlin Speedo goggles.
So, what's this rough blurry stuff? My initial suspicion many years ago about the glass deforming (or spidering as I called it) wasn't correct. That blurry part is lime scale gunk or something similar. I don't know where it came from although it may be from pool water. Apparently I didn't do much goggle cleaning after swimming. If you notice, the gunk settle at the outer area of the lens and I assume this was because of how the goggle is stored.
How did I confirm it was lime scale gunk? Well, a week ago I bought a lime scale remover called Simple Green Lime Scale Remover and this was for the purpose of cleaning bathroom faucets. I tried a few drops on the inside of the goggle lens and viola! A few minutes later, the gunk simply lifted after scratching the inside with my fingernail.
So after cleaning all the lenses, this his how they all looked like. Sadly, I didn't manage to get all the blurriness out but hey, it was still a big improvement!
Of course I had to disassemble the goggles to do that. And looking above, I have an extra blue lens. Why do I have an extra blue lens? It happened when its partner lens broke at the hook. Reminder to self - do not pull hard on the lens when adjusting. The lens hook for the nose piece is the lens' weakest part.
So now I have an extra 3 pairs again!