Fogging masks are an annoyance that every diver has had to deal with. Proper application of spit, anti-fog, whatever and care to not avoid the delicate layer of slime before or during the dive preoccupies too much time for me.
I recently received an anti-fog product sample called Sven Can See (I do not know who Sven is). The product is intended for more uses than just diving, but obviously that will be my focus here.
The application itself is quite simple: spray the dry lens once and use your finger to spread it around to cover the lens (sounds familiar, right?). The instructions state to cover both sides, but for scuba divers only the inside should suffice, as the outside is in constant contact with the water.
By the way, after reading our article about why masks fog and how anti-fog works, it should be clear how SCS is working.
The product then needs to dry for 10 minutes, which means anti-fog needs to be on your mind slightly sooner than you may be accustomed. To me, this was the only annoyance with the product, as I had to do a little more planning ahead.
However, once dry, you are good to go, which leads me to my favorite part: Sven Can See maintains the coating over multiple dives! This means no re-application before each dive.
I tried the product on a recent trip to Thailand, so I was curious just how many dives it would last before re-application was necessary. By the fifth dive my lens was beginning to fog in a few spots, enough where I considered myself inconvenienced. I should note that the first three dives were on a different day than the fourth and fifth.
From this quick test I would recommend that each morning the diver reapply the product and then forget about anti-fog for the entire day's dives. Then, when rinsing gear at the end of the day, rinse of the lenses well so that it is ready for application the next morning.
I did not go in to this with high expectations, but I think this is a substantially better system than using SeaDrops or spit or other products. The product is about twice as expensive, but given the reduced applications, should break about even or better.
Note: I noticed some poor product reviews from other divers. It is highly likely that these users did not apply the product properly. In particular, the lens must be dry before application and allowed 10 minutes. It does not need to be rinsed like traditional drops. I hope that helps some confused divers out there.