Some people use protectors, as the glass is prone to damage from stone impacts.
Protectors are relatively cheap, compared to replacement fog units.
There are the "stuck on with velco" type variety and the "Laminex" bonded-on variety.
Not sure what you mean by "splitters the fog", though
I will either be purchasing either yellow protectors, or 2500k yellow bulbs to improve the performance of my fogs, in the not too distant future.