Would the seating position of a road bike cause issues with prescription glasses I currently use a mountain bike to commute to work but I am keen to switch to a bike more suited to commuting. I have been looking at road and cyclecross bikes but I am concerned the more horizontal seating position of these sorts of bikes would cause issue with my glasses; specifically, I would end up peering over the top of my lenses rather than through them. Is this a common problem? Do I need to worry?
Yes, in most cases normal prescription glasses sit too low on the nose for the purpose of shielding the eyes in road bike position. And as the speed increases, the need for effective eye protection grows, too. Consider either:


Getting contact lenses, and then you can wear bike specific glasses
Getting bike glasses with prescription lens inserts. In my experience, they are somewhat awkward to handle and not all optometrists will undertake fitting the lenses to what they perceive as nonstandard frames.