The visor certainly helps - mine broke away 6 months ago, but the helmet is undamaged. Its almost impossible to find replacement brims.
So you might want to think about your technique. Try riding more defensively:
- Learn to See rather than Look - that's noticing motion through a raindrop or obstruction.
- Position yourself on the road to avoid possible problems.
- Light yourself and your bike up like the Eiffel Tower / Blackpool Tower / Big Glowing thing. More lights and high-vis the better.
Finally check with your optometrist whether rainx or friends might damage your glasses. It should be fine on glass lenses, but coatings might suffer. I wouldn't want to guess on plastic lenses.
If you're getting a new prescription soon, consider getting custom cycling glasses.
Here's a set that put the rain barrier in front of the corrective lens, so the light focussing is less distorted by rain.
Here's another photo showing from the side. Notice how the tinted plastic bit comes much further around the head, reducing that eye-drying side-buffeting on a fast downhill. The corrective lens part can be ground to your prescription by your optometrist. Depending on model, the front shield may be removable, and may even come with up to 5 or 6 different shades for different riding conditions. You can even get some models with a safety strap instead of two temples, so they're almost like baby's glasses or slightly like swimming goggles.
On later thoughts - that foam top band could be both awesome for sweat control, and horrible once it saturates.
I can't wear contacts because they irritate, and I have to wear glasses all the time, so would have to carry normal glasses on a ride too.