thinning fur along the eyes and side of face

....and I know what is causing it. When my kittens are grooming themselves, especially after eating, both kittens are rubbing themselves so hard that they they are rubbing the fur off of their faces. What, if anything, can I do about this? It is more obvious now that their fur is thickening because of the weather.
Do any of you have this going on with your cats/kittens?
Thanks

Its normal for cats to have thin hair between the ears and eyes (more noticable on darker shorthair cats), but you might want to have them checked by a vet to be sure its not ringworm or something else that is causing the hair loss.