I went and got my eyes checked and ordered new glasses last week. I'm sure no one needs a blow by blow telling of the process, and even telling you that my prescription has changed but a little, and everything looked fine is probably more information than you need, although it makes me happy.
What I really want to recommend is for my friends who have glasses or need glasses - and particularly those with diabetes, like me - to find an optometrist who has a retinal camera. The shop I went to this time, new for me since our insurance provider has changed since my last pair of glasses, had one. Instead of dilating your eyes, a process which isn't painful in and of itself, but takes time to achieve, and then recover from, you get a picture taken of the back of your eye. Look at the little red dot. Flash. Now on the other side, flash. Oh look on the screen there, everything looks normal. How easy is that? Nothing to put INTO your eye. Over in a moment. AND you get to see what the back of your eye looks like too! OK, I couldn't interpret those pictures either, but they can. I just think they are COOL!
Retinal camera. Find an optometrist that uses one.