Camera Dioptics

On my previous camera I had to use a dioptic adjustment attachment for the viewfinder and it worked well. This does bring up something worth thinking about. When buying a new camera, Is the dioptic range built in large enough for those who have to wear glasses but don't want to for taking photos? Depending obviously on eye sight vision.
My Nikon D300 has a greater dioptic range than my previous cameras, so not every model in a manufacturers range are the same in this respect. Also the way they can be viewed to adjust clarity through the viewfinder is different.

Bazza