Trouble seeing while driving at night, being blind temporarily when driving against car lights...?

I'm asking this because I'm concerned about my mom, who has just turned 42 and wears prescription gles. She had informed me of having trouble driving at night straining to see, especially when cars are driving past her opposite direction with their headlights. Even if the cars just have their low lights on, she goes temporarily blind. What could be a possible cause? We understand that she would need to see a optometrist/ophthalmologist, but what could we/she do in the meantime to help with the problem? We've read that vitamin A is often ociated with helping with night blindness. Would this vitamin be of some help? Or would the vitamin only help some lesser problem (if her night blindness is more severe or different than most other cases)