My neighbors' cart has those slotted vents at the bottom, that's the windshield you get from Villages Discount Golf Carts and they really don't do any good. I know years ago I had the wind problem when riding a motorcycle and sunglasses didn't work, so I had a full face shield. For the cart now we always put the top down and I wear Oakley Sunglasses, I have 4 pairs, they're not cheap but I get them on eBay for about half the price or go to Walmart and in the fishing department you can find similar no-name glasses for $15.
These are Oakley Radar Path, I have four different colors of these. The white and blue frames with the blue lenses I get a lot of compliments or people asking where I got them.
For back-up, I have a couple of pair of these from Walmart. I even have them in amber lenses which is great on a cloudy day or at sunset.