Happened to me. My eyes improved to the extent that I did not need my specs for reading or distance . On visiting the optician he recommended that I got tested for diabetes. Hba1c was 117, put on Type 2 medication. Eyesight gradually deteriorated and was struggling with specs so had eyes retested, bg finger test readings had come down to acceptable levels, Needed new specs. These were fine for a number of weeks but then I found them too strong and reverted to my old specs. Went back to optician he confirmed my prescription had changed yet again. Was closer to my pre diabetic prescription. The optician of course would not replace lenses free of charge in my new specs but has agreed to reduced price when bloods are stable and I decide to have yet a further retest.
I shall be making an appt next week as my Hba1c is now 41.