If he has VSS (which I believe he does), then yes, his night vision is weaker than most humans. Of course, he's out driving around at night anyway, so it can't be that bad. It can be compared to having floaters (those little squiggly things many of us have in our vision) but it's distributed like snow over the visual field. Some compare it to static on an old TV. It obscures vision more than floaters do, apparently. There seems to be no cure and very little evidence of spontaneous remission, either.
This is based on the TapATalk posts (see media thread) and on looking into the medical literature on VSS.
At any rate, his vision ought to have been worse at night, if he has VSS, is what I'm saying. Of course, it may not be severe enough to impair night driving, especially if roads are well marked. OTOH, it could help explain why he stops soon after he leaves Moscow on the night of the crime, gets his bearings, etc.
VSS was first explored in the medical literature in the late 1800's/early 1900's. Dr. Bleuler (Freud's mentor) mentions it. I had never heard of it until this case.
Brief article (recent):
Visual snow syndrome
IME, IMO.