Light conditions may vary throughout the day. Different lenses are created to accommodate these changing light conditions. When it comes to swapping out a lens, some goggles frames make it easier than others.
Lenses that fall into the category of, Easy, requires minimal effort and handling of the frame and lens when swapping or replacing. These goggles will usually have a mechanism that releases the lens from the frame so you don’t have to pull the frame away from the lens.
Lenses that fall into the category of, Moderate, means that the goggle frame does not pull away from the lens easily and requires time/handling when changing to a new lens.
Goggles that have lenses which are Permanent means that the lens is fixed and you are unable to swap it out for a different lens.