In two simple ways is the age-old spectacles problem approached: the headset now has an adjustable assembly, letting you extend or contract the distance between your eyes and the Oculus' lenses. This means you can create a larger space for your glasses, avoiding any discomfort.
The second way is quite nifty: variable eye cups.
What these are, essentially, is prescription lenses built into the headset. Unfortunately, these aren't exact prescription lenses, they won't be the equivalent of wearing a pair of tailor-made glasses, they will however be an approximation. This will be enough for all but those with the more extreme corrective glasses.
If you fall into that band able to use the lenses you won't need to wear your glasses at all under the headset.
You should really read the rest of the blog post, it's a great look into the process of manufacturing a piece of complicated technology. It's full of nuggets like the fact that every headset is spun about in a heated sauna to determine if the sensors are slightly misaligned and, if they are, the on-board software will then calibrate the sensors to cope with these minor differences. This means that every Oculus is slightly different.
The factory-made Oculus should be shipping, on schedule, in March.