I took my family skiing awhile ago and I was also concerned about the same thing. Especially since I knew I would be stressed, dealing with kids on slopes. I looked for ski googles with a high UV rating, like the highest I could find. They make ski googles in a wide range of UV rating. I picked a pair that eliminated the most glare. I was also blessed that when we ended up going it was an overcast day, but I still wore my googles. Googles were also great since it blocked out all light, even on the sides of the face.
I have an astigmatism, so my eyes have a hard time focusing without my prescription eye glasses. So I made sure the glasses could be worn underneath my googles.
If you plan to go a lot, I would invest in a pair of googles that have good reviews for eliminating the most glare from the snow and sun. These might cost more, but I believe would be worth it. I didn't have to splurge on my families googles and they were fine. But I knew the glare would do me in within an hour if I wasn't careful.
I also made sure to keep my abortive medications on me while on the slopes and because I was also fearful of altitude sickness bringing on a migraine, I began taking precautions to combat that days in advance. Hydrate, hydrate, hydrate. Basically, while having fun, I made sure to plan in advance and stop and take care of myself - and also other members of the family since they could just as easily get altitude sickness too.