Wiley-X has sunglasses that have a removeable gasket that turns them into goggles. They won't fit over your regular glasses, but you can get the lenses cut for your prescription. However, in summer riding in Oklahoma, any goggles are going to fog up and/or cause problems with sweat buildup around your eyes.

The wiley-x glasses are pretty close fitting even without the gasket installed though and will probably still help.

There are safety glasses that are designed to fit over regular glasses. They would provide a measure of protection from bugs, but since they are in front of your regular glasses, they don't provide much wind protection. They do have side shields which might help a bit. you wouldn't win any style contests with them.

There is also at least one company that makes a curved wind/debris shield that attaches to you helmet and extends down below your eyes. This would have less fogging problems and may provide some wind protection. It certainly would be compatible with your regular glasses. Unfortunately, I don't recall the brand or product names.