Polarised lenses eliminate it, some people stick a sun glass lens in front of their dash cams to fix them as well.
I wonder if that could explain it. Most of the time I'm wearing prescription sunglasses. The only time I don't is when it's very dull or at night.
Well it certainly would if your prescription sunglasses are polarised. Next Time it is sunny try with regular glasses?
I'm not sure if they are or not but I think not. They were bought with my normal glasses as a special offer so I assume they are just corrective lenses that have been tinted. My normal glasses have an anti-glare coating though so that would probably help as well.
Hmm.
Apparently not:
"Antireflective ophthalmic lenses should not be confused with polarized lenses, which decrease (by absorption) the visible glare of sun reflected off surfaces such as sand, water, and roads. The term "antireflective" relates to the reflection from the surface of the lens itself, not the origin of the light that reaches the lens."
But I might have got polarised lenses for normal use as I vaguely recall someone saying it could help when playing golf.
Whaever - glasses use certainly seems a likely explanation now that you've mentioned it.