I've been wearing contacts for 25 years. The reason I got them to begin with was when I started racing bicycles and needed my peripheral vision back.
I've just reached the age where I have no close vision at all without my "cheaters." A couple of months ago I had a stye in my eye and had to go without contacts for a week or so, so I went riding in glasses. I really enjoyed being able to read the maps on my computer without having to stop and dig my cheaters out of my jersey pocket! I didn't miss my peripheral vision as much as I thought I would.
What I missed most was my rear-view mirror, since it won't fit on my prescription glasses, only my sunglasses.
I'm back to wearing my contacts now. But honestly I don't have a strong feeling either way about which is best for cycling, for myself with my presbyopia. The higher the speed, the more I miss the peripheral vision. I definitely took it easy on the descents when I was wearing glasses, and I'd never wear glasses on the motorcycle if I could help it. My rides were in the country though. In traffic, it would be a whole different situation, and I agree with MP.
Speed comes from what you put behind you. - Judi Ketteler