Originally Posted by trekker pete

Yes, a branch across the face would suck. I highly recommend eyewear when single tracking.

The op asked about commuting and mentioned the problems with glare from oncoming headlights. I also struggle with this and have yet to find a pair of glasses that deal effectively with it. I usually do wear glasses during my commute, particularly in the morning when I have a few high speed descents and there is virtually no traffic. In the evening, there is a fair bit and I find that being blinded by oncoming headlight glare is more hazardous than the chance of catching a faceful of branch or a bug. I have good lighting so I should see the branch ahead of time if one happens to grow along my route over night.

I do have a pair of the yellow tinted glasses and like them for overcast days. I prefer clear ones for riding in the dark though for the reason mentioned above. They inhibit depth perception. You can't have too much depth perception when you are bombing down a hill at 40 mph.