You don't specifically mention what high-altitude activity you have in mind. If you're mountaineering, then get glacier gogglestheir side panels and mount for nose-shields makes them ideal. Julbo's Micropores ($90) are a first-rate glacier glass than can be fitted with prescription lenses. If you want the glasses for all-around use, then a good sports glass would work. Oakley, for instance, will make nearly any of their glasses to order with your prescription. Or, you can retrofit many glasses with prescription lenses.
In either case, ask around for a local optometrist who has some experience with mountaineering and high-altitude stuff. Surely Billings has one. You need more than "might work" for words of recommendationyou need someone who KNOWS what will work.
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