Those rearview cams you see on ebay won't be good enough when you use it upfront. The IR LED's (used for illumination) aren't just strong enough and/or the camera not sensitive enough. Otherwise, a lot would've been using them by now for the same reason as yours.

Not being funny, but in addition to the advices on proper (and legal) lighting, have you ever considered having your eyes checked? Another way is to match your driving speed to the driving conditions, like slowing down when visibility is impaired.