OCT scan at specsavers.

Floss

Teddysmum, maybe you could have the same frames again to save having to choose new ones? Personally with diabetes and glaucoma in my family I won't skip diabetes-related tests as once any damage is done it's not always recoverable. 

sheramber

You can  lower your mask to below your nose to try on frames.
The OCT is more  in depth than the routine one done when you have diabetes.