I totally understand why you wouldn't want her to have to visit the vet unnecessarily. The stress is worse than anything else, sometimes.
What a pity there aren't "mobile vets" who would visit animals in their own homes....
I really have no idea about the shrinking eye and eye socket problem, and have no experience with a dog with dabetes.
But I think you do need to ask her vet this question. It might be important...or it might be a regular thing....I can't say.
A good idea maybe would be if you could arrange a time to speak to the vet on the phone about it? Obviously she HAS been seen by her vet (not too long ago??) for her to have those prescriptions. He/she may insist on actualy examining her, or might at least be able to tell you if this is "normal" or needs attention.
My own dog was always terrified at the vet's, so I understand.