Rain-X ? I used that on my headlights in the Winter, it makes scraping frost and ice off very easy, but I never saw a frost at all last 'winter'. It does keep them cleaner.
I don't like it on the windscreen though funnily enough, I found it eventually degrades and gets very smeary.
But headlights, yes.
There's new intensely hydrophobic coatings coming, that may be even better and can even coat bodywork, even clothing. Imagine, after a day out in the muddy countryside, a clean car and no more bad brown marks on our clothes.