I've read that dust can be a real problem while on safari, especially for contact lens wearers. What is the best thing to wear? I have clear, plastic safety goggles (used in woodshop). I also found these yellow-tinted, wrap-around safety glasses used for target shooting. For the ultimate protection, I suppose I could wear swimming goggles. Any suggestions?

Yes, dust can be a problem, especially with contact lenses. But remember, you also need to consider optical quality of the glasses or whatever you wear over your eyes as well as sun protection--sometimes you will need sunglasses. You're going to Africa to see the place, so you want whatever you wear to work toward that, not against it.

I've never seen anyone with swimming googles--probably because the optical quality isn't good enough?

Most of the time good wraparound sunglasses work, and after dark clear plastic googles (of good quality) might be useful if it does get dusty. If you are lucky, you won't need them.

It's really important for contact lense wearers to carry wetting solution, some sort of purely refreshing eyedrops AND antibiotic eyedrops in case you scratch your cornea. You'll need a prescription to get appropriate drops.

The other alternative is to just wear glasses instead of contacts--many people choose this option. And you should bring prescription glasses in any case, just in the event that you can't wear your lenses due to irritation.