Eliminate Lens Fogging

Having your vision impaired in the middle of a skirmish can be very dangerous. Fogging occurs when the outside of your lens is a different temperature than the inside, causing condensation to occur. Steaming can happen from the evaporation of sweat or the condensation from your breath coming up into your goggles during an intense game. Goggles with good ventilation will minimize these problems, especially if you keep moving to increase airflow.

If you encounter severe fog or steam problems during a game, DO NOT remove your goggles to wipe them unless you are in a designated safe zone. Even in a safe zone, make sure to be aware of your surroundings, and try to get assistance from another player. If there are no teammates around to help you, simply call yourself out so you can take care of the problem. Once you are safe to remove your goggles, wipe the inside dry with a microfiber or other anti-scratch cloth. Do not use tissue or anything else that will flake apart and stick to the lens. Also avoid using any sort of cleaning solution that will affect the coating on the lens.

Here are some options to prevent fog and steam issues:

Thermal Lenses
The lens of a thermal goggle is made with two lens panes. The air trapped between the two lenses prevents a drastic temperature difference between the outer and inner lenses, which in turn prevents condensation. The inner lens on thermal goggles tends to be much softer than the outer lens, so be sure to clean them with care to avoid scratches. Steam issues are still possible on a thermal lens, but it is generally less of a problem.

Goggle Fans
A goggle fan attaches to the frame of your goggle and has a wire that runs along the headband to an external battery and switch. While they are a bit cumbersome, they offer excellent air flow even while staying still. Make sure to check that your pair of goggles has a frame that supports a fan before buying one.

Anti-Fog Solution
Anti-fog coating is very hit or miss. Many lenses come with a coating that prevents fog, but that will never prevent it entirely. The eye protection built to Military standards generally have less fogging issues out of the box. There are after-market products such as "Cat Crap" that can be applied to the inside of a lens as needed to help prevent fogging. A search around forums will reveal some household products that may work, including toothpaste, shaving cream, or plain old spit!

Note that your results will vary with any anti-fog solution, home-made or store bought. It is possible they will damage your lens, especially the cheaper ones. Any existing fog protection, anti-scratch coating, or the reflective properties could be affected