How do goggles get scratched?
Are you sure that is the right question? For me, the critical failure mode seems to the inexorable buildup of a translucent film of scale/scum that can't be washed off. Eventually this film interferes with vision sufficiently that the goggles are not longer safe to use.
Thanks to all responders for your input.
After reviewing these responses, and some careful thought and diligent observation, I think most of my goggle scratching troubles were the result of tossing them loose in my bag. I use an Aqua Sphere swim mask now which comes with a case which I keep it in.
If I'm not mistaken, however, the more common racing type goggles from Speedo don't come with a case; which seems like an important omission.
For me, the critical failure mode seems to the inexorable buildup of a translucent film of scale/scum that can't be washed off. Along with my goggles, I purchased a bottle of Aqua Sphere Anti-Fog (ASAF) liquid. While I't's unclear to me that it has any particular anti-fogging capabilities, it has clearly shown itself to be excellent at cleaning the goggles. After going a long time without using the product, my goggles were getting hard to see through. I applied the ASAF all over the goggles, not just on the lenses, and it cleaned them up very nicely.
That also helped them at least a little bit to not fog up; but I think the non-fogging may have had more to do with them just being clean than any special properties the Anti-Fog solution provided.
I noticed that a lot of goggle get that scratchy look when the anti-fog starts coming off. Something more of a smear, maybe? But any touching on the inside of the goggle will definitely remove or smear the coating and look like a scratch. So annoying. I try to just rinse them with water and hang them up without touching the inside lenses (obviously) and apply new anti fog coating when they start to look cloudy or scratchy.
