I ride a reclined recumbent which makes things even worse as I’m not really able to tilt my head down.
Wearing a cycling cap (under a helmet) helps a lot on a normal bike.
I tend to keep my glasses coated with anti-rain and anti-fog solutions – I’m currently using some from a company called Sal Clear. It seems to work well, especially when freshly applied, but the anti-rain stuff really stinks! I’m planning to try a different product (can’t remember the name) which seems to get good reviews.
I’m not sure anything works in fog/very fine rain. It lands on my glasses and turns them into soft-focus filters. There’s not enough weight in the water droplets to allow them to run off (that’s a technical explanation!) On a recent foggy ride I had to remove my glasses, but then I couldn’t see. I also found it difficult to balance due to the unusual vision!
My eyes aren’t suitable for contact lenses – I imagine they must be a good solution if you’re able to use them.