>>347796518
If you don't wear glasses and have the lenses as close to your eyes as possible as Gabe intended you will end up getting condensation from your eyes accumulating on the lenses. 
Because of the fan is essential.

If you look inside the frunk the top inner wall is an open vent. The fan blows away from the headset and that pull air in around your face through the headset and out the vent so the heat and moisture can't build up.