Some people have remarked that these onion goggles are a cheap rip-off. I recently received a pair of these from my wishlist as a birthday gift. The quality seems very good to me. I think that, perhaps, RSVP must have changed manufacturers for a while during 07 to 08, realized they were crap, and found a better manufacturer. I have not seen glasses from prior to 07 to be able to compare today's goggles with them, but I do know that the product I received is of a good quality.
The glasses are shaped like wrap-around sunglasses, curved to fit the shape of the face. Behind the frame that surrounds the lenses is a light foam material that creates a seal with your face. This foam has a layer of material (a little like a very thin black polyester flannel) that covers the part of the foam that touches your skin. This material makes the foam more comfortable, as well as strengthening the foam's edge--which without the support looks like it could easily tear. There are no ventilation holes cut into the foam.
Just like many wrap-around sunglasses, the fit of these onion-goggles is pretty snug. If you have a large head (like I do), don't expect to be wearing these for a long period of time (like for dry eyes.) While the fit is snug on me, (23" circumference head, size large hat) I find that I can wear them for at least a half an hour without discomfort--plenty of time to chop a lot of onions.
As the foam creates a seal between the nose and eyes, I did not have a problem with fogging. The foam seems porous enough that some circulation of humidity could occur. Interestingly, though, this did not seem to allow the onion fumes in.
The fumes. I could still smell the onions. The fumes still irritated my sinuses. But interestingly, the fumes did not affect my eyes. While I could feel a little burn in my nose, I had none of the tears (and consequently none of the runny nose) of cutting onions.
Fact: As long as they create a seal against your face, they work.
The glasses come in a soft plastic glasses case, which you can keep them in for storage. The case has a magnetic closure, which is nice when your hands are covered with meatloaf and you don't want to grab hard at the plastic to struggle with a snap.
Why did I give them only 4 stars? According to the Vision Council of America, 64% of adult Americans wear glasses. There is absolutely no way to fit a pair of glasses beneath these onion goggles. If you have a pair of contacts you can switch into--great! But good luck taking the contacts out after you've been cutting onions. It's clear that it would be difficult to create a good seal against onion fumes around a pair of glasses, but if ski-goggle manufacturers can do it, couldn't the onion goggle people? They could offer it as a separate product.
My prescription is around -2.0. I had no trouble cutting onions without my glasses on. But if your vision is worse, do a test drive at home, cutting onions without your glasses on, before you buy these.
I have not tested these goggles to see how easy they are to clean. I suspect soap and water and a gentle touch with a towel.
Last note: my cousin, who rides motorcycles, was at my birthday party. She commented that these looked almost exactly like motorcycle glasses. If you have ski goggles, motorcycle goggles, or a gas mask, give them a try. (Don't laugh--my dad was in the military and my mom used to use his old gas mask.)